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DEFENCE ESTATE ORGANISATIONMINISTRY OF DEFENCE

Specification 037

Air conditioning, air cooling andmechanical ventilation for buildings

This specification supersedes the former PSA StandardSpecification (M & E) No. 100

October 1997

INDUSTRIAL PROCESSES GROUPDEFENCE ESTATE ORGANISATION

Ministry of Defence

London: The Stationery Office

MINISTRY Of DEFENCE

BIAKEMOREDRSVE,

ACCESSION No. COPY1

MAIN

Crown copyright 1998. Published with the permission of the Ministry ofDefence on behalf of the Controller of Her Stationery OfficeApplications for reproduction should be made in writing to TheCopyright Unit, Her Majesty's Stationery Office, St Clements House,2-16 Colegate, Norwich NR3 1BQFirst published May 1998ISBN 0 11 772857 8

References updated to July 1997Prepared by Ove Arup and Partners on behalf of the Defence EstateOrganisationCover photograph by kind permission of the InternationalConvention Centre, Birmingham

Contents

Contents

Schedules

Tables

Foreword

Abbreviations

Amendmends

1 General Requirements1.1 Scope1.2 Definitions1.3 Related Documents1.4 Proven Performance1.5 Standards1.6 Acts and Regulations1.7 Electricity Supply1.8 Electrical Equipment and Wiring1.9 Drawings1.10 Calculations1.11 Maintenance and Operation Documents1.12 Corrosion Prevention and Painting1.13 CFCs and HCFCs1.14 Identification of Services1.15 Storage and Protection1.16 Rationalisation of Supplies1.17 Samples1.18 Schedules

2 Refrigeration Plant2.1 General2.2 Reciprocating Compressors2.3 Centrifugal Compressors2.4 Screw Compressors2.5 Scroll Compressors2.6 Absorption Refrigeration2.7 Water Chilling Evaporators (Shell and Tube Type)2.8 Air Cooling Evaporators (Dx Coolers)2.9 Air-cooled Condensers2.10 Evaporative Condensers2.11 Condensers (Shell and Tube Type)

Page

iii

ix

X

xi

xii

xiii

111112222444444555

678899

1010111111

October 1997 iii

2.122.132.142.152.162.17

33.13.23.33.43.53.63.73.8

44.14.24.34.44.54.64.74.84.94.10

55.15.25.35.45.55.65.7

66.16.26.36.4

77.17.27.37.47.57.6

7.7

88.1

Pressure TestingRefrigeration Plant Accessories and ControlsRefrigerant PipingThermal InsulationDry Coolers (Air-cooled Fluid Coolers)Cooling Towers

FansGeneralCentrifugal FansAxial Flow FansIn-line Centrifugal and Mixed Flow FansPropeller FansMechanical Roof Extract UnitsPackaged Duplicate-fan Extract UnitsProtectively — Coated Fans and Fans for Corrosive or HazardousApplications

Air FiltersGeneralFilter Cell Holding Frames, Seals and GasketsFire PropertiesPerformance CertificationFilter GradesBag or Extended Surface Type FiltersPanel FiltersHigh Efficiency Particulate Air (HEPA) FiltersActivated Carbon and Adsorption FiltersGrease Eliminators

Air Heater and Cooler BatteriesGeneralTestsHot Water Heater BatteriesSteam Heater BatteriesElectrical Heater BatteriesChilled Water Cooler BatteriesDirect-expansion Refrigerant Cooler Batteries

Air Washing and PlantGeneralSteam HumidifiersUltra-sonic Type HumidifiersDrainageen

Air Handling UnitsGeneralConstructionThermal and Acoustic InsulationDampersFansProvisions for Automatic Controls, Sensors, Instruments and TestHolesOutdoor Units

Ductwork, Dampers and Terminal DevicesFabrication Drawings

121213141415

19202121212222

22

23232323242424252526

28292930303030

32323333

3535363636

3636

38

October 1997

8.28.38.48.58.68.78.88.98.108.118.128.138.148.158.168.17

9

9.19.29.39.49.59.6

1010.110.210.310.410.5

11

11.111.211.311.411.511.6

1212.112.212.312.412.512.612.712.812.912.1012.1112.1212.13

Sheet Metal DuctworkInstallationInspection and TestsPlastics DuctworkAluminium DuctworkPvc Coated Sheet Steel DuctworkSteel Ductwork, Galvanised after manufactureStainless Steel DuctworkBendable Ducts and Flexible DuctsLightweight DuctingDampersAccess Openings, Cleaning and Inspection CoversHoodsTest HolesIdentificationAir Terminal Devices

Air Control Devices Including Induction, Terminal Reheatand VAV UnitsGeneralInduction UnitsSingle and Dual Duct Terminal UnitsVariable Air Volume (VAV) UnitsUnderfloor Fan-assisted Air UnitsConstant Volume Flow Regulators

Fan Coil UnitsGeneralCasingsComponentsArrangement of UnitsControls, Dampers and Grilles

Ventilating, Kitchen Ventilating and Chilled Ceilings,Chilled Beams and Platform FloorsGeneralVentilating CeilingsVentilating Platform FloorsKitchen Ventilating CeilingsChilled CeilingsChilled Beams

In-room Air Conditioning UnitsGeneralConstructionUnitary Reverse Cycle Heat PumpsInsulationGrillesAir FiltersFansRefrigeration EquipmentHumidifiersHeatersCoolersControlsElectrical Requirements

38383939393939393940404142424242

454545464646

4747474848

494950505050

52525253535353535353535353

October 1997

1313.113.213.313.413.513.613.713.8

1414.114.214.314.414.514.614.714.814.914.1014.1114.12

1515.115.215.315.415.515.615.715.815.915.1015.1115.12

1616.116.2

1717.117.2

17.317.4

17.517.617.7

1818.118.218.3

Water PumpsGeneralCentrifugal PumpsTwin Pump SetsCanned Rotor PumpsStand-by PumpsGaugesDrivesSump Pumps

PipeworkGeneralMaterialsJointsFlexible Piping ConnectionsFlexible ConnectorsWeldingBrazingAncillary EquipmentDraining and Flushing ProvisionsInstallationProvision for TestsProvision for Chemical Cleaning and Water Treatment

Valves, Cocks and StrainersGeneralMaterials and ConstructionIsolating ValvesCheck ValvesRegulating and Double Regulating ValvesSystem Commissioning Valve SetsDrain ValvesAir CocksValve OperationStrainersValve LabellingValve Schedules

Water Storage VesselsCisterns and Cold Water TanksChilled and Condenser Water Buffer Vessels

Thermal InsulationGeneralDuctwork and Air Handling Plant — Insulation Materials andFinishesDuctwork and Air Handling Plant — Methods of ApplicationChilled Water Pipework and Equipment — Insulation Materialsand FinishesChilled Water Pipework and Equipment — Methods of ApplicationVapour BarriersPainting and Identification

Water TreatmentGeneralPretreatment PlantWater Sampling and Test Equipment

5454555555555555

565656575757585960606262

656565666666666666676767

6868

69

7071

72737374

777778

October 1997

18.418.518.6

19

Chemical Dosing and Bleed-offCorrosion Monitoring EquipmentStorage of Chemicals

Heat Wheels, Heat Pipes, Air and Water Plate Heat

787878

Exchangers and Run-around Coils19.119.219.319.419.519.6

2020.120.220.320.420.5

2121.121.221.321.421.521.621.7

2222.122.222.322.422.522.622.7

2323.123.223.323.423.523.623.723.823.9

2424.124.224.324.424.524.624.7

GeneralHeat WheelsHeat Pipe UnitsPlate Heat Exchangers (Air)Plate Heat Exchangers (Water)Run-around Coils

Belt Drives, Variable Speed Drives and GuardsBelt DrivesVariable Speed DrivesBelt Drive PulleysGuardsElectric Motors

Vibration Isolation and Noise InsulationAnti-vibration ProvisionsNoiseNoise Insulation (Airborne Noise)Circular and Rectangular AttenuatorsSound Absorbent Ductwork LiningsFixing of Thermal and Acoustic LiningsAcoustic Enclosures

InstrumentsGeneralAir System Pressure GaugesAir System ThermometersWater System ThermometersPressure GaugesFilter Differential Pressure IndicatorsRemote Reading Thermometers

Automatic ControlsGeneralAir Compressor Plant for Pneumatic Controls SystemsControl Equipment FeaturesSensing ElementsMotorised DampersAir Heater ControlAir Cooler ControlHumidifier ControlControls for Water Cooling and Chilling Plant

Starter and Control PanelsGeneralPanel ArrangementMaterials and ConstructionPanel WiringIdentification LabelsVentilationInstruments and Indication

797979798080

8181818282

83838383848484

85858586868787

888889899090909090

91919192929292

October 1997 vii

24.8 Starters and Control Gear24.9 Automatic Control24.10 Testing24.11 Screening and Interference

25 Electrical Equipment and Wiring25.1 Scope25.2 General25.3 Electric Motors25.4 Electrical Wiring25.5 Screening and Interference

26 Testing and Commissioning26.1 Definitions26.2 General26.3 Cleaning26.4 Testing26.5 Commissioning of Water and Air Distribution Systems26.6 Commissioning of Specialist Equipment26.7 Commissioning Results26.8 Performance Testing26.9 Sound Level Measurements

27 Maintenance and Operation Procedures and Documents27.1 Installer Maintenance Procedures27.2 Instruction Procedures27.3 Maintenance and Operation Documents

viii October 1997

93939494

9595959595

97979898999999

Schedules

Schedule No. 1: Information for the Tenderer Supplied by the Design Office1 (of addendum)

(17 pages)

Schedule No. 2: Information to Be Supplied by the Tenderer1 (of addendum)

(36 pages)

October 1997

Tables

Refrigerant Tube DimensionsIntervals Between Support Centres for RefrigerantPipeworkMinimum Design and Test Pressures for RefrigerationEquipmentFilter ClassesSelection Table for Tubes and Pipes for Chilled Water,Condenser Cooling Water and Condensate DrainageInstallationsIntervals Between Support Centres for Steel PipeworkIntervals Between Support Centres for Copper PipeworkIntervals Between Supportcentres for Plastics Pipework(Contents Not Exceeding 20c)Economic Thickness of Insulation on Ductwork CarryingWarm AirMinimum Thickness for Insulation for Condensation Controlon Ductwork Carrying Chilled AirMinimum Thickness of Insulation for Chilled and Cold WaterSupplies to Prevent Condensation on A High EmissivityOuter Surface (0.9) with An Ambient Temperature of + 25Ecand A Relative Humidity of 80 % R.h.Minimum Thickness of Insulation for Chilled and Cold WaterSupplies to Prevent Condensation on A Low EmissivityOuter Surface (0.2) with An Ambient Temperature of + 25cand A Relative Humidity of 80 % R.h.

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17

17

1827

636464

64

75

75

76

76

PageTable 2a:Table 2b:

Table 2c:

Table 4a:Table 14a:

Table 14bTable 14cTable 14d

Table 17a

Table 17b

Table 17c

Table 17d

Foreword

This Specification is one of a series prepared by the Defence EstateOrganisation primarily for use in its contracts for mechanical andelectrical engineering works. The Specification covers the installation ofheating, hot and cold water, steam and gas services for buildings otherthan dwellings. It is a revision of the former Standard Specification (M&E)No. 100, dated 1990.

When this Specification is used in connection with Defence contract then itis to be read in conjunction with such further documents setting outcontractual requirements particular to the contract.

Whilst this Specification was commissioned by the DEO for use on MODcontracts, it is acknowledged that it could be usefully applied to othercontracts. DEO commend its use to other Government departments. It maytherefore be used outside the MOD estate. However, no warranty is givenas to the accuracy of this Specification or its fitness for any purpose.

This Specification has been devised for the use of the Crown and itscontractors in the execution of contracts for the Crown. The Crown herebyexcludes all liability (other than liability for death or personal injury)whatsoever and howsoever arising (including, but without limitation,negligence on the part of the Crown, its servants or agents) for any loss ordamage however caused where the document is used for any otherpurpose.

October 1997

1.

2.

3.

4.

Abbreviations

Acrylonitrile butadiene styreneAir Handling UnitAmerican Society for Testing and MaterialsBritish Board of AgrementBuilding management systemBritish StandardBritish Standards InstitutionBrisitsh Standard Pipe (thread)Building Services Research and Information AssociationBritish WaterEuropean Committee of Manufacturers of RefrigerationEquipmentCo-ordination Committee for Project InformationChlorofluorocarbonChartered Institution of Building Services EngineersBritish Standard Code of PracticeDioctyl phthalateDefence Estate OrganisationDirect-expansionElectric resistance weldedGlass reinforced plasticsHigh efficiency particulate arrestorHealth and Safety ExecutiveHigh temperature hot waterHeating and Ventilation Contractors' AssociationInstitution of Electrical EngineersInternational Standards OrganisationLow temperature hot waterMechanical and ElectricalMethod of BuildingMinistry of DefenceMedium temperature hot waterNational Measurement Accreditation ServiceNon-destructive testingNoise ratingOutside diameterProject ManagerPolytetrafluoroethylenePolyvinyl chlorideVariable air volumealternating currentdirect current

October 1997

ABSAHUASTMBBABMSBSBSIBSPBSRIABWCECOMAF

CCPICFCCIBSECPDOPDEODXERWGRPHEPAHSEHTHWHVCAIEEISOLTHWM&EMOBMODMTHWNAMASNTDNRO/DPMPTFEPVCVAVa.c.d.c.

The following abbreviations are used in this specification:

Amendments

Please use this table to make a note of any amendments issued.

October 1997 xiii

xiv October 1997

Specification 037Air conditioning, air cooling andmechanical ventilation for buildings

Section One—General Requirements

1 . 1 SCOPE

1.1.1 This Specification details the design andother requirements for air conditioning, air coolingand mechanical ventilation for buildings.

1.1.2 Unless otherwise indicated, the Work shallinclude design, manufacture, works testing, supply,delivery to site, installation, site testing,commissioning, performance testing, making good anydefects that occur during the defect liability period,provision of 'As Installed' drawings and Maintenanceand Operation documents, the whole of the labour andall materials necessary to form a complete installation(whether or not all the necessary components areindicated). The work also includes any ParticularSpecification Scope of Work.

1.1.3 Installer Maintenance shall be provided inaccordance with Section Twenty-Seven—Maintenanceand Operation Procedures and Documents—of thisSpecification.

1.1.4 Unless otherwise indicated, all equipmentand materials to be installed shall be new.

1.1.5 The Contractor shall ensure that allequipment can be installed in the allotted spaces andshall maintain adequate access for maintenance andrepair.

1.1.6 All equipment shall be installed inaccordance with the manufacturer's writteninstructions.

1.2 DEFINITIONS

1.2.1 'Project Manager' (PM) shall mean anofficial of the MOD or commercial representativeresponsible for the purpose of management andadministration of the works covered within thisSpecification.

1.2.2 Where the work is to be undertaken as asub-contract, 'Contractor' shall mean 'Sub-contractor'.

1.2.3 'Indicate' as used in 'as indicated', 'whereindicated', 'unless otherwise indicated' and likephrases shall mean indicated in Schedule No. 1 of thisSpecification or in the other documents listed in theinvitation to tender.

1.2.4 'Comment' means comment in writing by thePM, unless stated otherwise.

1.3 RELATED DOCUMENTS

1.3.1 This Specification shall be read inconjunction with, and its requirements are in additionto, the general conditions of contract and anydrawings and other documents issued with it andlisted in the invitation to tender.

1.3.2 Any discrepancy between this Specification,the Conditions of Contract, other documents listed onthe tender form or the Contract Drawings shall bereferred to the relevant person designated in thetender documents as soon as practicable during pre-acceptance stage or to the PM thereafter.

1.4 PROVEN PERFORMANCE

1.4.1 Systems and equipment selected by theContractor shall have a successful proven performancefor not less than 2 years under equivalent conditionsto those required by the tender documents. Systemsand equipment that do not comply with the foregoingproven performance period may be consideredprovided full technical details and evidence ofsuitability are given at the time of tendering.

1.5 STANDARDS

1.5.1 Commodities specified to conform to BritishStandards shall be clearly and indelibly marked withthe reference specified. Where this is impracticable,the relevant advice and delivery notes shall includethe BS reference with which they are to comply.

October 1997



1.5.2 Where commodities are specified asmanufactured by a BSI Kitemark Licensee or wherecommodities/services are specified to be by RegisteredFirms (under BSI Assessment Schemes), themanufacturer/firm must be a current participant inthe relevant scheme.

1.5.3 Where commodities or systems are specifiedas certified by the British Board of Agrement, thecommodities or systems supplied shall be the subjectof a current BBA Certificate.

1.5.4 Where commodities/services are specified tobe by registered/approved firms (under ApprovedQuality Assurance Schemes), the manufacturer/firmmust be a current participant in the relevant scheme.

1.5.5 The equipment and/or installation(s) shallconform to the relevant British Standards and Codesof Practice current 3 months prior to the date forreturn of tenders, unless otherwise indicated.Certificates or compliance with British Standards, BSICertification Schemes, and/or Quality AssuranceSchemes, shall be provided to the PM at his request.

1.6 ACTS AND REGULATIONS

1.6.1 All work shall be carried out in accordancewith the relevant Safety Regulations which may beseen on request to the PM.

1.6.2 The installation(s) shall comply with allActs, relevant Statutory Instruments, Regulations,and Special Guidance and Memoranda which includethe following:

a) The Health and Safety at Work, etc, Act.

b) Regulations under the Electricity Acts.

c) The Clean Air Act.

d) Control of Pollution Act.

e) Energy Conservation Act.

f) Regulations under the Factories Act.

g) The Building Regulations.

h) The Gas Safety (Installation and Use)Regulations.

j) The Control of Substances Hazardous toHealth Regulations (COSHH).

k) The Pressure Systems and Transportable GasContainers Regulations.

1) The Construction (Design and Management)Regulations (CONDAM).

m) The Management of Health and Safety atWork Regulations (MHSW).

n) The Personal Protective Equipment at WorkRegulations (PPE).

o) BS 7671: 1992 (Requirements for electricalinstallations, The IEE Wiring Regulations.(Sixteenth Edition)

p) British Gas Codes of Practice.

q) The Institution of Gas Engineers UtilizationProcedures (IGE/UP)

r) The Electricity at Work Act

s) Any special requirements of the LocalElectricity, Gas or Water Undertakings andFire Fighting Authority.

t) The Asbestos Regulations.

u) HSE Guidance Note HS(G)70—The control oflegionellosis (including Legionnaires' disease).

v) CIBSE Technical Memoranda TM13: 1991—Minimising the risk of Legionnaires' Disease.

1.7 ELECTRICITY SUPPLY

1.7.1 Unless otherwise indicated, all apparatusand wiring shall be suitable for use with a three-phase, four-wire, 400/230-V, 50-Hz, earthed neutralsystem.

1.8 ELECTRICAL EQUIPMENT AND WIRING

1.8.1 Bonding of all extraneous conductive partsof the installation (including metallic pipework,ductwork, insulation cladding etc.) shall be carried outin accordance with BS 7671 and BS 7430 (Code ofpractice for earthing).

1.9 DRAWINGS

1.9.1 Working drawings

1.9.1.1 Unless otherwise indicated, the Contractorshall provide working drawings for comment beforemanufacture or installation. The drawings shall show:

a) fully dimensioned builder's workrequirements,

b) plant room details,

October 1997



c) general arrangement of the completeinstallation,

d) ductwork and pipework support details,

e) ductwork and pipework fabrication details,

f) details of any changes resulting fromInstructions given by the PM or agreementsreached with him,

g) purpose-made diagrams detailing theelectrical and/or pneumatic circuitry withinthe installations,

h) manufacturers 'as-made' drawings whererequired by this Specification.

1.9.1.2 Comment on such drawings by the PM shallnot relieve the Contractor of responsibility for anydiscrepancies, errors or omissions therein. Thenumber of sets of drawings indicated shall be sent tothe PM in time to meet the contract programme,allowing a minimum of 3 weeks, or as otherwiseagreed with the PM, for examination and approval.Any amended drawings shall be provided at theContractor's expense.

1.9.2 Electrical, Electronic and PneumaticDiagrams

1.9.2.1 Composite circuit and layout diagrams forelectrical, electronic and pneumatic services shallinclude all circuitry within main control panelstogether with connection diagrams for all externalequipment such as starters, all forms of controldevices, air conditioning, cooling and ventilationequipment, together with all inter-connecting wiringor pneumatic pipework from the main point of supplyonwards and all termination markings. All circuit andlayout diagrams shall include explanatory notes andshall show the required sizes and types of all cablesand pipework together with the ratings of such itemsas fuses, switches and pneumatic controls.

1.9.2.2 Circuit diagrams shall, where possible, bearranged so that the main sequence of events is fromleft to right and from top to bottom of the diagram.Symbols for electrical diagrams shall comply with BSEN 60617. Where abbreviations are used for thedesignation of components, an integral schedule shallbe provided on the drawings to explain the meaningsof the abbreviations.

1.9.2.3 A print of each of the composite circuit andlayout diagrams shall be fixed securely to the inside ofthe hinged front of the main electrical and pneumaticcontrol panels, as appropriate, or in such other

alternative positions as may be agreed with the PM,and shall be protected by non-flammable transparentmaterial. Where inadequate space exists, the printsshall be suitably reduced in size.

1.9.2.4 Individual circuit and layout drawings fromthe various component manufacturers will not beaccepted in lieu of composite diagrams.

1.9.3 'As installed' drawings

1.9.3.1 The Contractor shall provide 4 sets of'AsInstalled' drawings unless otherwise indicated.

1.9.3.2 Unless otherwise indicated, the drawingsshall show the following:

a) the complete installation including the sizesand routes of all ductwork and pipework,

b) the location and identification number of alldampers,

c) the location and identification number of allterminal units, fan coil units, grilles, registersand diffusers,

d) the location and identification number of eachpipework isolating, regulating and controlvalve in accordance with the labelling andcircuit control diagram required by SectionFifteen—Valves, Cocks and Strainers—of theSpecification,

e) the location and identification of serviceswhich are buried within the structure orunderground,

f) the manufacturer's name, model and typenumber and full details of duty and rating forall items of plant including control equipment.

1.9.3.3 Electrical 'As Installed' drawings shall beprovided in accordance with DEO Specification 034.

1.9.3.4 Each drawing shall be in accordance withBS 308: Part 1 and shall be a process negative ontranslucent material, not paper, of a standard sizefrom AO to A4. The words 'AS INSTALLED' shall beinserted in 19mm block letters adjacent to the titleblock of each drawing, together with the name of thesite, section of the Works, the title of the installation,the date of completion of the Works, the contractnumber and the name of the Contractor. Eachdrawing shall be dated.

October 1997



Where the drawings are supplied to the Contractor inCAD files the Contractor shall additionally provide the'AS-INSTALLED' information in similar format.Where indicated Microfiche copies shall be provided.

1.9.3.5 During the course of the Works, theContractor shall maintain a fully detailed record of allchanges from the tender drawings to facilitate easyand accurate preparation of the 'As Installed'drawings and to ensure that these drawings are in allrespects a true record of the installation.

1.9.3.6 The symbols used for individual 'AsInstalled' drawings shall be identified on eachdrawing.

1.9.3.7 The electrical, electronic and pneumaticdiagrams detailed in Clauses 1.9.2.1 and 1.9.2.2 shallform part of the set of 'As Installed' drawings.

1 . 1 0 CALCULATIONS

1.10.1 The Contractor shall submit fan and pumphead calculations prior to ordering any such item.

1 . 1 1 MAINTENANCE AND OPERATION DOCUMENTS

1.11.1 Maintenance and Operation documents shallbe provided in accordance with Section Twenty-Seven—Maintenance and Operation Procedures andDocuments—of this Specification.

1 . 1 2 CORROSION PREVENTION AND PAINTING

1.12.1 Ferrous sheet materials shall receive aprotective coating of paint at works after suitablepreparation, or be treated with the manufacturer'sapproved corrosion-resisting metal finishing process.Any deterioration or damage to the manufacturer'sprotective coating shall be made good as if bare metaland to the satisfaction of the PM.

1.12.2 The Contractor shall be responsible fordecorative painting to:

a) water storage vessels as detailed in SectionSixteen—Water Storage Vessels—of thisSpecification.

b) thermal insulation as detailed in SectionSeventeen—Thermal Insulation—of thisSpecification.

1.12.3 The surfaces of all ferrous metal workincluding pipework, brackets, hangers, steelwork etc.which are not protected by galvanising, works-appliedprimer, or protective paint shall be suitably preparedand painted with one coat of zinc phosphate primer.

All such surfaces, with the exception of pipeworkwhich is to be insulated, shall be finished with twocoats of approved quality non-metallic paint of acolour agreed with the PM. Where surfaces will besubjected to temperatures above 100°C, the finishingcoat(s) shall be heat-resisting paint, and the primernormally omitted. Manufacturer's instructions shall bestrictly followed in the preparation for, and theapplication of paint.

1.12.4 The Contractor shall ensure that those partsof the installation required to be left unpainted (eg.brasswork), shall be so left.

1.12.5 When the Works covered by theSpecification are carried out as a sub-contract, theBuilding Contractor will apply, free of cost to theContractor, the priming and finishing coats exceptthose to water storage vessels and thermal insulationas detailed in Clause 1.12.2 and those elementsspecified in Sections Sixteen and Seventeen. Wherethere is no Building Contractor, the Contractor shallbe responsible for the decorative painting.

1 . 1 3 CFCSANDHCFCS

1.13.1 Products containing and/or requiring the useof CFCs or HCFCs in their manufacture, are only tobe used if permitted by current MOD policy.

1 . 1 4 IDENTIFICATION OF SERVICES

1.14.1 Pipework and ductwork service installationsshall be identified by colour band code and/or symbolsin accordance with Section Seventeen—ThermalInsulation—of this Specification.

1 . 1 5 STORAGE AND PROTECTION

1.15.1 All materials and equipment items shall beproperly stored, as required by manufacturers'instructions where applicable. Particular care shall betaken to ensure that electrical equipment andcomponents are kept dry and free from dust.

1.15.2 Pipes shall be racked clear of the groundand ends shall be closed with purpose-made temporarystoppers or seals.

1.15.3 Fittings, valves, jointing components andother sundry items shall be stored in clean bins or bebagged and stored in suitable racks.

1.15.4 All work shall be protected during theContract Period.

October 1997



1 . 1 6 RATIONALISATION OF SUPPLIES

1.16.1 Items, fittings and accessories to be used inquantity shall, where practicable, be the product ofone manufacturer and shall be used only for thepurpose recommended by that manufacturer.

1 . 1 7 SAMPLES

1.17.1 The Contractor shall, as requested and priorto placing orders, provide samples for inspection bythe PM. The samples shall be as indicated.

1 . 1 8 SCHEDULES

1.18.1 Schedule No. 1 to this Specification givesinformation to tenderers relating to the clauses whereoptions or specific numbers etc. require stating.

1.18.2 Schedule No. 2 to this Specification is fortenderers to complete and return as part of theirtenders.

October 1997


Section Two—Refrigeration Plant

2.1 GENERAL

Note: Operatives engaged on work to refrigerationsystems shall be fully trained; be in possession of anappropriate training record; and be registered withthe Refrigeration Industrial Board as RegisteredHandlers of Refrigerants. Operatives shall have aCertificate of Achievement for Safe Handling ofFluorocarbon Refrigerants showing the registrationreference number and date of registration.

2.1.1 Mechanical vapour compressionrefrigeration plant shall use hydrogenated CFCs(HCFC) or hydrofluorocarbons (HFC) or otherrefrigerant having zero Ozone Depletion Potential(ODP) approved by the PM. The plant shall include allaccessories necessary to ensure continuous andreliable automatic operation. The design maximumcooling rate shall be achieved at the maximumambient conditions indicated. Each unit shall becapable of running continuously at the lowest step ofcooling capacity without any adverse effect. The plantshall be charged with lubricant, and be provided witha holding charge of refrigerant or inert gas beforedispatch from the Works where a full charge isimpractical.

2.1.2 Installations shall comply with BS 4434,The Safety Code for Refrigerating Systems UtilisingChlorofluorocarbons—Part 1' published by theInstitute of Refrigeration, and CECOMAF DocumentGT1-001.

2.1.3 Refrigerants Rll and R12 shall not beoffered for any new cooling plant installations.

2.1.4 Any refrigerant used shall be fullycompatible with all materials comprising the completerefrigeration system.

2.1.5 Where Rll or R12 have to be removed fromexisting installations, the disposal shall be carried outas required by CECOMAF document GT1-001.

2.1.6 Rating tables, physical data and capacitycurves relevant to the selection of the equipment shallbe available for a range of operating conditions and bebased on manufacturer's test results. Pressure dropvalues for water-cooled condensers and evaporatorsshall be determined from test results and shall be ableto be verified. Fouling factors shall be stated inSchedule No. 2. See also Clauses 2.7.1 and 2.11.1.

2.1.7 Major components shall be readily accessiblefor maintenance and arranged to facilitate removalwithout disturbing other system components.

2.1.8 Semi-hermetic and hermetic compressorswill only be acceptable on complete factory assembledrefrigeration systems, condensing units or chillercompressor sets provided the units are:

a) fully charged at manufacturer's works, or

b) complete with holding charge of refrigerant orinert gas on arrival at site.

2.1.9 Open type compressors shall have areplaceable rotary mechanical seal fitted to the drivingshaft which prevents leakage of refrigerant and oil.For direct-coupled type units of input power greaterthan 25kW, flexible drive couplings shall be of a typewhich enables the shaft seal to be removed withoutmoving the compressor or motor.

2.1.10 All parts of refrigerant gas cooled motorsshall be proof against long-term contact withrefrigerants and compressor lubricating oil.

2.1.11 The motor of a compressor which isrefrigerant gas cooled shall have in-built protectionagainst inadequate cooling.

2.1.12 The oil pump of three-phase semi-hermeticand hermetic compressors shall either operate equallywell under each direction of rotation or have specialarrangements made to prevent reverse rotation.

October 1997



2.1.13 A resiliently mounted control centre on orclose to the refrigeration unit shall house the controland protection equipment.

2.1.14 Visual indication of operation of all safetyprotection devices shall be provided.

2.1.15 Where indicated, provision shall be made forremote indication of each alarm condition and forremote indication of all outputs to a buildingmanagement system (BMS) or other control system asindicated.

2.1.16 Hours-run meters shall be provided to allcompressors in excess of 6kW input power.

2.1.17 The noise level in the space, from each unitoperating at its design duty, shall not exceed NR90.Acoustic data shall be provided including octave bandanalysis of the sound power level of the unit underfree-field conditions.

2.2 RECIPROCATING COMPRESSORS

2.2.1 Main rotating and reciprocating componentsshall be statically and dynamically balanced.Crankshafts and eccentric shafts of all open or semi-hermetic compressors having an input power to thecompressor in excess of 2.25kW shall run inreplaceable bearings.

2.2.2 Pistons greater than 50mm diameter shallbe fitted with either:

a) two compression rings and one oil controlring, or

b) a combination of compression ring(s) and apiston specially shaped to act as an oilscraper.

2.2.3 All open and semi-hermetic compressorshaving an input power to the compressor in excess ofthe following, shall have:

a) Removable cylinder liners (50kW compressorinput power and above only).

b) Side and/or end covers which will enableservicing or repair of the unit to be carriedout situ' or local to the installation byvirtue of ready removal (25kW compressorinput power and above only).

c) A crankshaft-driven oil pump used to force-feed lubricant to the main and big endbearings and the shaft seal (6kW compressor

input power and above only). A filter and oilsuction strainer shall be incorporated withinthe oil lubrication system.

d) An oil pressure relief valve or bleed deviceprovided between the oil pump discharge andthe crankcase (6kW compressor input powerand above only).

2.2.4have:

a)

Open and semi-hermetic compressors shall

Provision for draining oil from the suctionmanifold into the crankcase and for ventingrefrigerant gas (but not oil) in the oppositedirection.

b) A crankcase heater, arranged to operate whilethe compressor is at rest; with protectionprovided to prevent starting before the oil hasreached the minimum operating temperature.

2.2.5 All types of compressor, except whereindicated below, shall have the following provided andconnected:

a)

b)

c)

Service stop valves on compressor suction anddischarge connections.

Resiliently oil-filled refrigerantpressure gauges of minimum 65mm diameter,fitted with means of isolation, on suction anddischarge with pressure calibrated in bar andsaturation temperature for the refrigerantused calibrated in °C (6kW compressor inputpower and above only. Capped valved pressuretappings shall be provided below 6kWcompressor input power).

Oil pressure gauge of minimum 65mmdiameter with means of isolation (compressorswith oil pump only).

d) Crankcase oil level sight glass (6kWcompressor input power and above only).

e) Low oil differential pressure safety cut-outwith hand reset (compressors with oil pump inexcess of l00kPa differential pressure only).

f) Refrigerant suction gas strainer.

g) Internal pressure relief valve on compressorsin excess of 35kW input power.

h) Vibration isolation incorporated in therefrigerant lines of compressors located onanti-vibration mountings or where refrigerantlines are likely to transmit vibration.

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2.2.6 Compressors having a refrigeration capacityin excess of 35kW shall have capacity control bymeans of either cylinder unloading or speed changeand shall be arranged so that starting is in theunloaded condition.

2.2.7 Hot gas injection into the refrigerant inlet ofthe evaporator will be permitted for capacity controlas follows:

a) on compressors below 35kW refrigerationcapacity, or

b) for compressors above 35kW, equal to thecapacity of the final step.

2.3 CENTRIFUGAL COMPRESSORS

2.3.1 The compressor shall have automaticcapacity regulation which will control at any pointfrom 10% to 100% of full duty without inducing asurge condition or vibration. The compressor shall notbe enabled to start unless in the fully unloadedcondition. Unless otherwise indicated, the hot gasbypass or injection system of capacity control will notbe accepted.

2.3.2 The lubrication system shall be arrangedwith an interlock to ensure adequate oil pressure atall bearings before the compressor starts and duringthe 'coast down' period including conditions due topower failure. A replaceable or cleanable filter shall bepositioned in the oil delivery pipe. A hand resetpressure or flow switch shall stop the compressor on alubrication system failure. Where an oil cooler is used,it shall be thermostatically controlled. The oil sumpshall have a thermostatically controlled electric heaterwhich operates while the compressor is at rest.

2.3.3 Where a multi-stage compressor isconsidered, it shall be shown that the work done ineach stage is balanced at part-load operation.

2.3.4 The following shall be provided andconnected:

a) Refrigerant pressure gauges as Clause 2.2.5 (b).

b) Oil pressure gauge as Clause 2.2.5 (c).

c) Oil sump or reservoir level sight glass.

d) Pressure operated safety cut-outs as Clause2.13.1 (b).

e) Low oil pressure cut-out or flow switch, bothwith hand reset facilities incorporated.

f) High oil temperature cut-out with hand reset.

g) High bearing temperature cut-out with handreset.

h) High motor temperature cut-out with handreset.

2.4 SCREW COMPRESSORS

2.4.1 The compressor shall have automaticcapacity control equipment which will control at anypoint between 10% and 100% of full duty. Thecompressor shall not be enabled to start unless in thefully unloaded condition.

2.4.2 The lubrication system shall be arrangedwith an interlock or other means to ensure adequateoil pressure at all bearings before the compressorstarts. A hand reset pressure or flow switch shall stopthe compressor on a lubrication system failure. Thepipeline from a positive displacement oil pump shallincorporate a pressure regulating valve to relieveexcess oil to the reservoir. A replaceable or cleanablefilter shall be positioned in the oil delivery pipe. Athermostatically controlled oil cooling system shall beused to remove heat gained by the oil. The oil sumpshall have a thermostatically controlled electric heater.Lubrication systems which obtain their pressure fromthe high pressure vapour side of the refrigerantsystem shall be allowed at the discretion of the PM.

2.4.3 A device shall be fitted to prevent thepressure differential across the compressor causingbackward rotation at a normal or emergency stop.

2.4.4 The following shall be provided andconnected:

a) Service stop valves on compressor suction anddischarge connections.

b) Refrigerant pressure gauges as Clause 2.2.5(b).

c) Oil pressure gauge as Clause 2.2.5 (c).

d) Oil reservoir level sight glass.

e) Low oil pressure cut-out or flow switch, bothwith hand reset facilities incorporated.

f) High oil temperature cut-out with hand reset.

g) Refrigerant suction gas strainer.

Compressors using oil injection for rotor sealing shallincorporate arrangements to prevent excessive oilcarry-over with refrigerant from the compressor andensure adequate oil return to the compressor over thefull operating range.

October 1997



2.4.5 Compressor units shall be suitable forcontinuous and automatic operation and be free ofvibration.

2.5 SCROLL COMPRESSORS

2.5.1 Scroll compressors shall be of heavyconstruction to eliminate resonance and vibration andproduce low operating sound level.

2.5.2 Compressors shall be hermetic type having awelded shell. Motors shall be suction gas cooled withsolid state safety protection devices.

2.5.3 Compressors shall incorporate a dischargetemperature thermostat and a refrigerant anti-reversal flow component.

2.5.4 The lubricating system shall include acentrifugal oil pump, oil heater and sight-glass.

2.5.5 Axial and radial fit of compression chambersurfaces shall be achieved with tip seals and swinglink connector of orbiting scroll to motor shaft.

2.5.6 Each refrigerant circuit shall include acompressor discharge service valve, liquid line shut-offsolenoid valve, filter-dryer and sight-glass.

2.5.7 The control panel shall include separatesections for motor starters and automatic controls.Compressor motor contactors, overload relays andtermination strips shall be contained in the startersection. System protection switches, compressor hoursrun, compressor starts limiter and ambienttemperature shall be contained in the controls section.

2.5.8 High and low pressure gauges shall beprovided.

2.5.9 Independent refrigerant circuits shall beprovided where indicated.

2.6 ABSORPTION REFRIGERATION

2.6.1 Absorption refrigeration shall be lithiumbromide/water systems with steam, hot water, ordirect firing as indicated, supplying chilled water orhot water.

2.6.2 Absorption equipment shall be single stageor two stage assemblies comprising:- generator(s),condenser, evaporator, absorber, solution heatexchanger(s), solution pump(s), refrigerant pump(s)and all associated interconnecting pipework andvalves. Unless otherwise indicated, duty and stand-bysolution and refrigerant pumps shall be provided.

2.6.3 Additional hot water heaters, to providesimultaneous heating and cooling, shall be providedwhere indicated.

2.6.4 Unless otherwise indicated absorptionequipment shall be hermetic packaged unit(s)assembled, leak tested, fully tested and adjusted atfactory and sealed before transportation to site.

2.6.5 Multiple units shall be provided withselective lead-lag controls.

2.6.6 Bursting discs to BS 2915: 1990 shall beprovided and installed to discharge safely inaccordance with the manufacturers instructions.

2.6.7 The design fouling factor for all watercircuits shall not be less than 0.00009 m2K/W.

2.6.8 Units shall be complete with a capacitycontrol system. Output shall be controlled by athermostat mounted in the chilled water outletmodulating heat energy input through an automaticcontrol valve.

2.6.9 Automatic de-crystallization shall beprovided by circulation of heated solution through theheat exchanger.

2.6.10 Anti-crystallization upon power interruptionshall be provided by dilution of solution in the heatexchanger.

2.6.11 An inhibitor (lithium chromate) shall beused within the solution circuits to reduce corrosiondue to possible ingress of air and to reduce stress-corrosion effects.

2.6.12 Auxiliary (heat recovery) condensers shall befitted to machines where indicated.

2.6.13 Piping connections to water boxes shall bemade with valved branch bends to permit access toevaporator and condenser tubes without dismantlingpiping systems. Vents and drains to water boxes shallbe provided. Water box connections shall be flanged toBS 4504 (or grooved end for mechanical joint.

2.6.14 The shell(s) shall be of welded carbon steelconstruction.

2.6.15 Absorber, generator, and evaporator tubesshall be cupro-nickel. Condenser tubes shall beseamless copper.

2.6.16 Tube ends shall be rolled into steel tubesheets welded to the shell and each tube shall beindividually replaceable. Access shall be provided toall tube bundles.

October 1997



2.6.17 Absorber, condenser, evaporator and hotwater heat exchanger pipework and headers shall besuitable for 10 bar working pressure.

2.6.18 Generator pipework and headers for steamunits shall be suitable for 10 bar workingand 28 bar working pressure for hot water units.

2.6.19 Water boxes including vent and drainconnections shall be cast iron, lined with corrosionresistant materials.

2.6.20 Motor cooling shall be integrally arrangedwithin the unit, complete with a suitable strainerassembly.

2.6.21 Pumps and motors shall be serviced andmaintained without removal of the absorbent solutionor refrigerant charge.

2.6.22 A cupro-nickel vessel shall be provided tocollect non-condensable gases and an electrical purgepump shall be connected and piped to discharge toatmosphere through a one-way discharge valve.

2.6.23 A factory-wired and mounted control panelshall contain:

a) terminal block

b) control voltage transformer and fused lowvoltage circuit

c) high motor temperature cut-out

d) low refrigerant temperature cut-out

e) time delay relay (dilution cycle)

f) pump motor starters

g) purge motor fuse

h) unit operating status lamps

2.6.24 A factory assembled and mounted capacitycontrol panel shall contain:

a) chilled water temperature controller

b) cooling water temperature controller

c) start-up demand limiter

d) part-load economy switch

For pneumatic controls the following additionalequipment and instruments shall be provided:

e) pressure switch

f) solenoid air control valve

g) 'supplied thermometer

h) 'supplied air' pressure gauge

j) 'branch air' pressure gauge

2.7 WATER CHILLING EVAPORATORS (SHELL ANDTUBE TYPE)

2.7.1 Unless otherwise indicated, evaporatorsshall be of the shell and tube type, capable of being re-tubed 'in situ'. An evaporator which cannot be re-tubed 'in situ' shall be readily removable. The designfouling factor on the water side shall not be less than0.00009 m2K/W unless otherwise indicated.

2.7.2 The shell and tube plates shall be of steeland the water boxes/end covers of cast iron or steel.The tubes shall be of copper, aluminium-brass, orcupro-nickel. The water-box end covers shall beremovable. Tube supports shall be fitted and may be ofpolypropylene, or other suitable and approvedmaterial, and shall prevent tube vibration. Waterconnections shall be flanged to BS 4504 or havegrooved ends for mechanical joint as indicated.

2.7.3 Water-side drain and air venting provisionsshall be made.

2.7.4 Provision shall be made on floodedevaporators for returning oil to the compressor. The oilrectification system shall ensure that refrigerant inthe liquid form is not returned to the compressor. Fulllength liquid droplet carry-over eliminators shall befitted.

2.7.5 Flooded evaporators shall be fitted with arefrigerant level controller.

2.7.6 The refrigerant passages in a direct-expansion water chiller shall ensure that oil present isalways carried through at the lowest stage of capacityreduction.

2.7.7 The refrigerant and water spaces shall bepressure tested at the manufacturer's works inaccordance with Clauses 2.12.1 to 2.12.3.

2.8 AIR COOLING EVAPORATORS (DX COOLERS)

2.8.1 Air coolers (evaporators) using the directexpansion of a primary refrigerant shall comply withthe relevant clauses of Section Five—Air Heater andCooler Batteries—of this Specification.

2.8.2 The design of the refrigerant passages shallensure that oil present is always carried through atthe lowest stage of capacity reduction.

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2.9 AIR-COOLED CONDENSERS

2.9.1 Heat exchanger materials shall be selectedto minimise electrolytic action, be suitable for theoperating conditions and be constructed fromrefrigerant quality seamless copper tubes with eitheraluminium, vinyl coated aluminium, copper, or electro-tinned copper fins, as indicated. Fins with minordamage shall be properly combed straight. Units withextensive damage to fins will not be accepted.Provision shall be made for the purging of non-condensables from the condenser.

2.9.2 Air-cooled condensers mounted outsidebuildings shall have weatherproof motors. The unitsshall discharge air vertically upwards unless they areprotected by an integral wind deflector or purpose-made baffle. The frame, supports and casing of unitsshall be constructed of material which is eithercorrosion resistant or made proof against corrosionafter manufacture.

2.9.3 Condenser design shall ensure equal airdistribution over the full coil surface(s).

2.9.4 Unless otherwise indicated, automaticcontrol of the condensing pressure shall beincorporated. Where modulation of the outlet dampersis used, each fan motor shall be selected for thisapplication and arranged so that it is de-energised oncomplete closure of the dampers.

2.9.5 Fans shall comply with Section Three—Fans—of this Specification, particular attention beinggiven to the permitted noise levels indicated, and shallbe weather-resistant. Fan outlets shall be suitablyprotected.

2.9.6 Completed coils shall be pressure tested atthe manufacturer's works in accordance with Clauses2.12.1 to 2.12.3.

2.9.7 Metal parts of condensers shall be bonded toearth. Lightning protection shall be provided whereindicated.

2.9.8 Air-cooled condensers assemblies shall befully accessible for thorough cleaning. Themanufacturer shall provide means and recommendfrequency.

2.10 EVAPORATIVE CONDENSERS

2.10.1 Evaporative condensers shall be of the typeindicated. The condenser coils shall be of plain steelpipe (galvanised after manufacture), copper pipe orstainless steel pipe as indicated. Each condenser shall

be complete with a water circulating pump complyingwith Section Thirteen—Water Pumps of thisSpecification with pump suction strainer.

2.10.2 The requirements of Clauses 2.17.2 to2.17.14 (with the exception of references to packingmaterial), shall apply to evaporative condensers.

2.10.3 Provisions shall be incorporated to eliminatewater freezing within the spray pump and floodedpipework during 'off periods. Provision shall be madefor the purging of non-condensibles from thecondenser and venting from the liquid receiver.

2.10.4 Unless otherwise indicated, automaticcontrol of the condensing pressure shall beincorporated. Where modulation of dampers is used,each fan motor shall be selected for the applicationand arranged so that it is de-energised on completeclosure of the dampers.

2.10.5 The completed condenser coil block shall bepressure tested at the manufacturer's works inaccordance with Clauses 2.12.1 to 2.12.3.

2.10.6 Cleaning and water treatment shall be inaccordance with Section Eighteen—Water Treatment—of this Specification.

2.10.7 Metal parts of condensers shall be bonded toearth. Lightning protection shall be provided whereindicated.

2.11 CONDENSERS (SHELL AND TUBE TYPE)

2.11.1 Shell and tube condensers shall have carbonsteel welded shells. Manually cleanable copper,aluminium-brass, or cupro-nickel tubes shall beexpanded into mild steel tube plates welded to theshell. All tubes shall be adequately supported andspaced, and shall be replaceable 'in situ'. Precautionsshall be taken to prevent tube vibration. The designfouling factor on the water side shall not be less than0.00018 m2K/W unless otherwise indicated.

2.11.2 Water boxes/end covers shall be cast iron orsteel protected against corrosion. End covers shall beremovable to permit tube inspection, easy cleaningand replacement. Water connections shall be flangedto BS 4504 or have grooved ends for mechanical jointas indicated. Condenser position shall be so arrangedto ensure tube removal or maintenance isunobstructed by pipework, valves etc.

2.11.3 Water-side drain and air venting provisionsshall be made.

October 1997 11



2.11.4 Unless otherwise indicated, automaticcontrol of the condensing pressure shall beincorporated.

2.11.5 Means shall be provided for a balancedconnection to the liquid receiver and for the controlledremoval of non-condensables from the refrigerant sideof the condenser. Automatic purge equipment shallhave a visual signal fitted to indicate excessive purgecycles.

2.11.6 The refrigerant and water spaces shall bepressure tested at the manufacturer's works inaccordance with Clauses 2.12.1 to 2.12.3.

2.12 PRESSURE TESTING

2.12.1 Refrigeration equipment shall have astrength pressure test and a leakage pressure testafter manufacture. Tests on the refrigerant side shallbe made in accordance with BS 4434.

2.12.2 A strength pressure test shall be applied tothe refrigerant system. The required test pressureshall be as shown in Table 2C of this Specification orBS 4434, whichever is the greater. Water-side pressuretests shall be 1.5 times the working pressure.

2.12.3 A leakage pressure test shall be applied tothe refrigerant system after all piping has been fitted.This test shall be in addition to the strength pressuretest on each unit at completion of manufacture. Therequired test pressure shall be as shown in Table 2Cor BS 4434, whichever is the greater.

2.13 REFRIGERATION PLANT ACCESSORIES ANDCONTROLS

2.13.1 Every refrigeration system shall beprotected by:

a) A pressure relief device unless it is soconstructed that pressure due to fireconditions would be safely relieved. Themeans of discharge and equipment providedshall comply with BS 4434 and the outletshall be piped to discharge outside thebuilding in a safe location.

b) High and low refrigeration pressure safetycut-outs with adjustable differential and setpoint. Hand reset to high pressure, hermeticunits of less than 7.5kW input power may befitted with factory-set high and low pressuresafety devices at the discretion of the PM.

Where applicable installations shall comply with therequirements of the Pressure Systems andTransportable Gas Containers Regulations. A writtenscheme for inspection shall be prepared by aCompetent Person.

2.13.2 Each refrigeration system with a refrigerantcontent greater than 10kg, shall be complete withsuitable connections for the safe removal of thecomplete refrigerant charge.

2.13.3 A liquid receiver shall be fitted to systemsusing an evaporative condenser or an air-cooledcondenser, unless the system is critically charged andutilises capillary tube flow control. The entire chargeshall be stored in 80% of the receiver volume. Forsystems having a water-cooled condenser withinsufficient capacity to take the complete refrigerantcharge, a liquid receiver shall be provided to make upthe deficiency. Liquid receivers shall have means ofventing, and means of determining liquid refrigerantlevel.

2.13.4 Where systems use a thermostatic expansionvalve, the following components shall be providedupstream in the refrigerant liquid line:

a) A hand shut-off valve.

b) A capped refrigerant charging valve.

c) A refrigerant drier (replaceable element type).

d) A refrigerant strainer.

e) A combination liquid sight glass and moistureindicator.

f) A solenoid valve.

2.13.5 Where an evaporator pressure regulatingvalve is fitted, a strainer and an evaporator pressuregauge provided with means of isolation, shall beinstalled upstream of the regulating valve.

2.13.6 Compressors which may be required to startwith exceptionally high evaporating temperatures,shall either have sufficient motor power available tomeet this condition or be fitted with a device orsystem to limit the maximum suction pressure.

2.13.7 Where the compressor is expected to start incold ambient conditions and the setting of the lowpressure cut-out is such that it may operate duringthe start sequence, a device or system shall beincorporated to override this cut-out until suitableoperating pressures have been established.

12 October 1997



2.13.8 Units having a direct-expansion evaporatorat a higher level than the compressor shall operate ona pump-down cycle. On water chilling installations,the chilled water pump shall continue running duringpump down.

2.13.9 The flow of refrigerant to a multiple circuitdirect-expansion evaporator shall be controlled by anexternally equalised thermostatic expansion valvewhich shall not 'hunt' at any step of compressorunloading.

2.13.10 In a system where oil circulation orrectification is difficult, an oil separator shall beincluded.

2.13.11 Refrigerant service valves shall be of thecapped type and incorporate a spindle gland of theback-seating type in which the gland is serviceablewith the valve 'in situ'.

2.13.12 Flow sensing arrangements shall beprovided in the chilled water pipeline to each shelland tube evaporator to prevent the compressor(s)starting or continuing to run if the water flow is belowthe minimum stipulated by the evaporatormanufacturer. Flow switches shall incorporate adamping device.

2.13.13 A low temperature thermostat with handreset shall be provided for each shell and tubeevaporator to stop the compressor(s) if the chilledwater flow temperature falls below 3°C.

2.13.14 Vibration isolation shall be provided towater chilling equipment in accordance with SectionTwenty-One—Vibration Isolation and NoiseInsulation—of this Specification.

2.13.15 Starter and control panels shall be providedin accordance with Section Twenty-Four—Starter andControl Panels—of this Specification.

2.14 REFRIGERANT PIPING

2.14.1 Design, materials and installation ofrefrigerant piping systems shall be in accordance withSection 4, Part 1, of the 'Safety Code for RefrigeratingSystems Utilising Chlorofluoro-carbons' published bythe Institute of Refrigeration. Piping shall be of copperor steel.

2.14.2 To minimise the possibility of refrigerantlosses to atmosphere, pipework joints shall be kept toa minimum. Wherever possible, brazing or welding ispreferable to flared, screwed or flanged connections.

2.14.3 All refrigerant pipework shall be designedfor the minimum pressure drop which ensures that oilin the refrigerant leaving the compressor is carriedthrough the system and back to the compressor at thelowest stage of capacity unloading.

2.14.4 Design shall ensure correct refrigerantdistribution to evaporator(s) with no liquid refrigerantdrainage into compressor(s) during shutdown norliquid entry during operation, and avoidance oflubricant accumulation and slugging in the suctionline.

2.14.5 Copper suction, discharge and liquid linesup to 41/8in (105mm) outside diameter (O/D) shall befabricated from refrigerant quality tube to BS 2871:Part 2, Table 2—material designation C106. Tubeshall be fully annealed up to 7/8in (22mm) outsidediameter (O/D) only. Tube shall be delivered to siteinternally degreased and shall be stored in clean anddry conditions with ends sealed until required forinstallation . Tube minimum dimensions shall be inaccordance with Table 2A of this Specification.

2.14.6 Suction, discharge and liquid lines in steelshall be fabricated from seamless pipe complying withBS 3602: Part 1—material grade 360 minimum orhigher quality.

2.14.7 Plastic pipe, with compression fittings to BS864: Part 3, may be used for feed piping to pressuregauges and similar fittings only where these aremounted on instrument or control panels. The gradesof pipe used shall withstand the test pressure appliedand the effects of refrigerant and oil. Plastic pipe willnot be accepted for any other refrigerant piping.

2.14.8 Flared joints in copper piping systems will beaccepted only on equipment accessories. Compressionfittings shall not be used except as Clause 2.14.7.Brazing shall be carried out in accordance with HVCA/JIB Recommended practice and tests for competency1990 (formerly HVCA Code of Practice TR/3) and BS1723. Brazing rods shall be cadmium-free and conformto BS 1845.

2.14.9 Joints in steel pipework shall be welded orflanged. Fabricated mitred or segmental bends, unlessforming an integral part of equipment design, will notbe permitted. Screwed joints will be accepted only onequipment accessories with either taper form threadsusing an approved sealing compound, or parallelthreads associated with machined joint faces and asuitable joint. Welding shall be carried out inaccordance with HVCA/JIB Recommended practiceand tests for competency 1990 (formerly HVCA Codeof Practice TR/5), BS 2971 and BS 2640.

October 1997 13



2.14.10 Brazers and welders shall be approved inaccordance with Section Fourteen—Pipework—of thisSpecification, or shall complete the standard testprocedure and gain a certificate of competency inaccordance with the two relevant HVCA/JIBdocuments.

2.14.11 Steel pipe shall be clean and free from allforms of debris including rust, mill scale, flux andwelding scale. Pipe shall be stored in clean dryconditions until required for installation. Ingress ofdirt and moisture shall be prevented at all times,including during fixing operations, by sealing or use ofend caps.

2.14.12 Piping shall be firmly supported inaccordance with Section Fourteen—Pipework—of thisSpecification and secured to minimise vibration.Centre spacings for refrigerant pipework shall notexceed those given in Table 2B of this Specification.Provision shall be made to accommodate thermalexpansion and contraction. 'Cold bridging' shall beprevented. Vibration eliminators shall be fitted to thecompressor suction and discharge pipes to minimisetransmission of vibration or noise. Where indicated, agas pulsation damper shall be fitted in the refrigerantdischarge pipe, in the plant room, as close as possibleto the refrigeration compressor.

2.14.13 After completion, the refrigerant pipeworkshall be subjected to pressure and leakage tests inaccordance with Clauses 2.12.2 and 2.12.3.

2.14.14 The use of a number of compressors eachhaving an independent refrigerant circuit in acommon evaporator will be permitted provided that anindependent pressure test in accordance with Clause2.12.2, and an independent leakage test in accordancewith Clause 2.12.3, is carried out on each refrigerantcircuit.

2.14.15 Two compressors may be connected inparallel if arrangements are incorporated to:

a) ensure adequate oil rectification and oilbalancing within compressors, and

b) eliminate accumulation of liquid refrigerantwithin delivery side fittings during anycompressor-off cycle.

2.15 THERMAL INSULATION

2.15.1 Materials shall be in accordance withSection Seventeen—Thermal Insulation—of thisSpecification. The insulation shall be protected by avapour barrier which shall not be broken down

between joints of sectional material nor atdiscontinuities at valves, fittings or supports. Theapplication method shall prevent the ingress ofmoisture through the insulation to the cold surface.The permeance of the vapour barrier shall not exceed0.01 g/(s MN).

The thickness of insulation shall be to BS 5422. Wherethe indicated thickness in BS 5422 tables is not acommercial size, the nearest larger commerciallyavailable thickness shall be provided.

2.15.2 Shell and tube evaporators shall beinsulated with a minimum thickness of insulationsuitable for the application. This shall be 19 mminsulation unless otherwise indicated. Where theinsulation does not possess a smooth surface suitablefor painting, a sheet metal casing shall be fitted. Theinsulation, (and casing where fitted), shall bearranged so that minimal damage is caused duringremoval of the evaporator end covers.

2.15.3 Liquid refrigerant pipes external tobuildings and subject to solar radiation shall either beshielded or have 12mm thickness (minimum) ofweatherproofed closed-cell insulation applied, with areflective or light coloured finish.

2.15.4 Discharge pipes likely to cause burns topersonnel shall be shielded.

2.16 DRY COOLERS (AIR-COOLED FLUID COOLERS)

2.16.1 The location of dry cooler(s), relative to thebuilding, shall not impede air flow through the unit.Where possible unit coils shall be protected fromdirect sunlight. Airflow through the unit shall not berestricted by associated water distribution pipework.

2.16.2 Heat exchanger materials shall be selectedto minimise electrolytic action, suitable for theoperating conditions and constructed from seamlesscopper tubes with either aluminium, vinyl coatedaluminium, copper or electro-tinned copper fins, asindicated. Fins with minor damage shall be properlycombed straight. Units with extensive damage to finswill not be accepted.

2.16.3 Coolers mounted outside buildings shallhave weatherproof motors. The units shall dischargeair vertically upwards unless protected by integralwind deflectors or purpose made cases. The frame,supports and casing of units shall be constructed ofmaterial which is either corrosion resistant or madeproof against corrosion after manufacture.

14 October 1997


Section Plant

2.16.4 Unit design shall ensure equal airdistribution over the full coil surface(s). For multi-fanarrangement, each fan shall be complete with bafflesor separate chambers to eliminate short circuiting andspinning of de-energised fans.

2.16.5 Water connections shall be male BSP orflanged to BS 4504 as indicated.

2.16.6 Fans shall comply with Section Three—Fans—of this Specification. Particular attention shallbe given to the permitted noise levels indicated. Fansshall be weather-resistant and fan outlets shall besuitably protected. Fan motors shall be single ormulti-speed type as indicated.

2.16.7 Unless otherwise indicated fans shall becontrolled individually or in pairs in conjunction witha step controller and fluid temperature sensor.

2.16.8 Cooler coils shall be tested before leavingthe manufacturer's works. A test certificate shallissued for each coil or each coil shall be indeliblymarked with details of the test.

2.16.9 Each cooler coil shall be leakage tested byusing air under water to 1.5 times the workingpressure or 8 bar gauge pressure, whichever is thegreater, for 30 minutes.

2.16.10 Self sealing test points, in accordance withSection Fourteen—Pipework—of this Specification,shall be provided on the inlet and outlet connectionsto each cooler.

2.16.11 Metal parts of coolers shall be bonded toearth. Lightning protection shall be provided whereindicated.

2.16.12 Dry coolers assemblies shall be fullyaccessible for thorough cleaning. The manufacturershall provide means and recommend frequency.

2.17 COOLING TOWERS

2.17.1 Cooling tower installations shall complywith CIBSE TM:13 and Health and Safety Executivepublication HS(G)70 and HSE L8.

2.17.2 Cooling towers shall be of the type indicated.The entering and leaving water temperatures, waterflow rate, and ambient wet-bulb design temperatureshall be as indicated. Tests shall be in accordance withBS 4485: Part 2 and Part 3, as applicable.

2.17.3 All parts of the unit shall be accessible forservicing and cleaning with fixed means of personnelaccess where indicated. A suitably sized water supply,terminating in a hose connection, shall be providedlocally to units for cleaning purposes.

2.17.4 All necessary joints and bracing in thecasing and pond constructions, (including associatedjointing components such as nuts, bolts, etc), shall bemade externally such that all internal surfaces are ofsmooth finish and free from obstructions. There shallbe no internal flanges or ledges, other than thosenecessary to support packing material or drifteliminators. All nuts, bolts and washers shall havecorrosion-resistant finishes. Self-tapping screws willnot be accepted.

2.17.5 Casings shall be of sheet steel, glassreinforced plastics or stainless steel as indicated. Thecasing shall have a treatment to minimise corrosion ordecay relevant to the casing material used. Detailsshall be indicated in Schedule No. 2. The casing andstructure shall withstand the maximum wind speedindicated.

2.17.6 Tower packing and drift eliminators shall beof plastics materials or glass reinforced plastics.Materials shall be resistant to fire, corrosion anddeterioration or decomposition due to condenser watertreatment chemicals, polluted air and insect attack.Plastics materials shall be self-extinguishing and beresistant to ultra-violet degradation.

2.17.7 Packing material shall not distort in anyway under normal use to cause obstruction to air orwater flow and shall be resistant to organic growth.Packing shall be designed to ensure that particulatematerial can drain into the sump for removal. Packingshall be readily cleanable and fitted in sections, eachseparately supported to facilitate removal.

2.17.8 The water distribution system shall beeasily removed and dismantled for cleaning. Whereopen distribution pans or troughs are used, they shallbe fitted with fine mesh grids to exclude debris. Wherespray nozzles are used, they shall be of non-ferrousmaterial, easily removable for cleaning and shall beprotected by a strainer.

2.17.9 Air inlets and outlets shall be arranged toavoid recycling and shall have mesh grids to preventingress of debris. High efficiency drift eliminatorsshall be provided which limit the drift loss rate to nomore than 0.001% of the water circulation rate. Theseeliminators shall have means of fitting which ensureseffective edge sealing to prevent drift by-pass andshall be removable in easily handled sections with air

October 1997 15



flow direction indelibly marked on each section. Theanticipated level of drift shall be stated in ScheduleNo. 2.

2.17.10 Sumps shall be sheet steel hot-dip zinccoated after manufacture, sheet steel anti-corrosion

glass reinforced plastics, sheet steel epoxycoated or stainless steel as indicated. Sumps shall bedesigned to collect sludge in such a way thatfacilitates its removal during cleaning operations. Thebottom of the sump shall be sloped towards the drainconnection.

2.17.11 The water reservoir shall be shielded fromdirect sunlight and shall be of sufficient depth abovethe outlet connection to prevent air entrainment inthe outlet pipe during operation. Sump capacity shallbe sufficient to prevent overflow when the systemshuts down. Sumps shall be fitted with grids of 15mmsquare mesh to exclude debris from the outlet pipes.An electric immersion heater, controlled by anadjustable thermostat and a low water level cut-outfloat switch, shall be fitted in the water reservoir.

2.17.12 Sumps shall have cold water make-upconnection with ball float valve or level control, quick-fill provision, overflow connection, drain connection,and outlet pipe with removable strainer and anti-vortex plate. The relative positions of the cold watermake-up and other pipe connections shall be arrangedto avoid creating stagnant water conditions. The drainconnection shall be at the lowest point in the sumpand shall be of adequate size to facilitate quick-draining of the sump.

2.17.13 Fans shall comply with Section Three—Fans—of this Specification and be of the centrifugal oraxial type, particular attention being given to the

permitted noise levels indicated. Fan casings andimpellers shall be made of corrosion-resistant materialor be completely proofed against corrosion aftermanufacture. Fan motors shall be totally enclosed andweatherproofed. Belt or gear drives shall be readilyaccessible and fully protected against the weather andshall comply with Section Twenty—Belt Drives,Variable Speed Drives and Guards—of thisSpecification.

2.17.14 Fan motors mounted in the moist airstreamof induced-draught units shall be epoxy coated or haveother means of corrosion prevention. Lubrication shallbe possible during operation of fans withoutcomponent removal and without possibility of over-lubrication. Fan bearings shall be designed to preventloss of lubricant and limit the ingress of dirt andmoisture.

2.17.15 A bleed pipe, with stop valve and flowregulating device, shall be provided on each unit fromthe water flow pipe. The bleed pipe shall be connectedinto the water flow pipe above basin water level andshall be extended to the nearest sump or gulley todischarge through an air break.

2.17.16 Cooling water piping connections shall beflanged to BS 4504 or have grooved ends formechanical joint as indicated.

2.17.17 Cleaning and water treatment shall be inaccordance with Section Eighteen—Water Treatment—of this Specification.

2.17.18 Metal parts of cooling towers shall bebonded to earth. Lightning protection shall beprovided where indicated.

16 October 1997



TABLE 2A: REFRIGERANT TUBE DIMENSIONS

TABLE 2B: INTERVALS BETWEEN SUPPORT CENTRES FOR REFRIGERANT PIPEWORK

October 1997 17


Section Plant

TABLE 2C: MINIMUM DESIGN AND TEST PRESSURES FOR REFRIGERATION EQUIPMENT

NOTE:1. This Table is retained for application to existing installations utilising CFC's.2. For ammonia (NH3, R717) systems, minimum values of design pressure with corresponding

strength test and leak test pressures shall be as Table Bl of the Institution of RefrigerationSafety Code for Compression Refrigerating Systems Utilizing Ammonia (1990).

3. Other replacement refrigerants for CFC's shall have pressure test values based on manufacturerspublished data for refrigerants, and Note 4.

4. Interim values shall be established from the following factors: Sat. pressure, minimum designpressure, and minimum leakage test pressure are approximately equal; strength test pressure(castings) equals 1.5 times sat. pressure; strength test pressure (rolled, drawn) equals 1.3 timessat. pressure; leakage test pressure (maximum) equals 1.1 times sat. pressure.

5. Tables of minimum values of design pressure with corresponding strength test and leak testpressure are in course of preparation by the Institution of Refrigeration and shall be used whenavailable.

18 October 1997


Section Three—Fans

3.1 GENERAL

3.1.1 Unless otherwise indicated, therequirements of this section shall not apply toindividual fans having a duty air flow rate of 0.5m3/sor less.

3.1.2 Mechanical and electrical safety provisionsfor fans shall be in accordance with BS 848: Part 5.

3.1.3 Fans shall be 'type' tested in accordancewith BS 848: Part 1 and Part 2 and be selected todeliver the required air volume flow rate and meet thenoise level indicated. Fan curves shall be submitted toindicate performance under all likely operatingconditions.

3.1.4 Values of resistance to air flow of items ofequipment, ductwork and/or the total distributionsystem, are indicated for tender purposes only. Thetotal system resistance shall be verified by theContractor, to ensure that fans provided are capable ofdelivering the required air volume when operatingagainst the actual total system resistance. TheContractor shall compensate for the manufacturers'certified resistance of all equipment being suppliedand any other variation to the total system resistancecaused by changes to fittings, ductwork layouts orductwork sizes.

3.1.5 Fans shall be constructed to proven designstandards and shall be capable of withstanding thepressures and stresses developed during continuousoperation at the selected duty, during starting, duringstopping and during speed and duty changes.Additionally, belt-driven fans shall be capable ofrunning continuously at 10% in excess of the selectedduty speed and shall have a minimum of two belts.

3.1.6 Fans shall be installed using bolts, nuts andwashers with all nuts properly locked and secured. All'as cast' bearing surfaces for bolt heads and washersshall be machine counterfaced. Holding-down bolts forfans and motors shall be provided with means toprevent the bolts turning when the nuts are tightened.

Anti-vibration mountings shall be in accordance withSection Twenty-One—Vibration Isolation and NoiseIsolation—of this Specification.

3.1.7 The shaft and impeller assembly of all fansshall be statically and dynamically balanced to BS6861: Part 1. Where indicated, limits of vibrationseverity shall be in accordance with BS 7854: Part 1.

3.1.8 Fan bearings shall be of a type suitable forthe size, speed, loads and discharge angle of the fanand shall be greased/oil ball and/or roller type, oillubricated sleeve type or sealed type where approved.Bearing housings shall be precision aligned andarranged so that bearings may be replaced withoutthe need for realignment. Bearing housings shall beprotected against the ingress of dust. For greaselubricated systems, the bearings shall be providedwith grease in the quantity and quality recommendedby the bearing manufacturer. Oil lubricated systemsshall have an adequate reservoir of oil. All bearinglubricators shall be located to facilitate maintenance.

3.1.9 Finishes and materials of construction shallnot be affected by gases handled by the fan or thelocal environment.

3.1.10 All electrical components and wiring shall bein accordance with Section Twenty-Five—ElectricalEquipment and Wiring—of this Specification.

3.1.11 Flexible connections for fans shall be inaccordance with Section Eight—Ductwork, Dampersand Terminal Devices—of this Specification.

3.1.12 Fan drive arrangements shall be inaccordance with Section Twenty—Belt Drives, VariableSpeed Drives and Guards—of this Specification.

3.1.13 Vibration isolation for fans and factory-applied acoustic linings in packaged duplicate-fanextract units shall be in accordance with SectionTwenty-One—Vibration Isolation and NoiseInsulation—of this Specification.

October 1997 19



3.1.14 Electric motors shall comply with SectionTwenty-Five—Electrical Equipment and Wiring—ofthis Specification.

3.2 CENTRIFUGAL FANS

3.2.1 Centrifugal fans for high pressure/highvelocity systems, (as defined within HVCASpecification DW/142), shall be of the backward bladedtype.

3.2.2 Unless otherwise indicated, centrifugal fansconsuming more than 7.5kW at the fan shaft shall beof the backward bladed type, selected for operation ata fan total efficiency not less than 75%.

3.2.3 Fan casings shall be mild steel sheet, withwelded or riveted joints and welded angle stiffeners,constructed to permit withdrawal of the fan impeller.Fans not in air handling units shall have flangedoutlet connections and spigoted inlet connectionsunless otherwise indicated. For negative pressure inexcess of 500 Pa, the inlet connection shall be flanged.All flanged connections shall be in accordance with BS6339. A plugged drain shall be fitted at the lowestpoint in the casing. Permanent indicators shall showthe direction of rotation of the impeller. Casings shallhave access panels incorporating air seals to facilitatecleaning and maintenance of the impeller.

3.2.4 Scrolls formed from galvanised mild steelsheet with lock formed joints and spot weldedsupports and bases shall not be used for fans with astatic pressure greater than 2 kPa. For toxic orhazardous application fan casing shall be gas tight allwelded construction.

3.2.5 Impellers shall be of mild steel protectedagainst corrosion or aluminium alloy. Impeller cagebraces shall be bolted, riveted or welded to the cageand hub. Stressed wire or threaded rod bracing shallnot be used. Bolted assemblies shall have lockingdevices.

3.2.6 Impellers of fans consuming more than1kWat the fan shaft shall be keyed to the driving shaft orfixed with tapered bush fittings.

3.2.7 Each fan impeller shall have a separateshaft. Where necessary, fan shafts shall be connectedwith flexible couplings to ensure correct alignment.

3.2.8 Each fan impeller shall be supported by anindividual bearing system.

3.2.9 Plummer block bearings or similar splitbearing housings shall be used on fans consumingmore than 4kW at the fan shaft. Where indicatedsealed for life rubber bushed bearings are acceptable.

3.2.10 Rubber bushed bearing housings withlateral deflections shall not be used on belt-driven fansconsuming more than 1kW at the fan shaft.

3.2.11 Belt-driven centrifugal fans and drivemotors shall be located on a common base.

3.2.12 Where indicated, fans shall be fitted withvariable pitch inlet guide vanes matched to the fanperformance to give stable control. Vanes shall beclosely interlocked to ensure movement in unison.Operation shall be manual or automatic as indicated.Where manual operation is indicated, the operatingdevice shall facilitate positive locking in at least fivedifferent positions. Vane blades shall not vibrate orflutter, nor be audible during movement. Linkageconstruction shall minimise friction and lost motion.The backlash between the guide vanes and the motoror actuator spindle shall not exceed 3% of the totalmovement required to obtain the operating range.100% of the motor or actuator travel shall be used toobtain the full range movement of the vanes.

3.2.13 Fans fitted with guide vanes shall havebackward curved blades. The guide vane assemblycontrol actuator(s) shall be supplied by the fanmanufacturer.

3.2.14 The guide vane assembly control shall fullymodulate throughout the operating range of volumesof the system served by the controlled fan. The staticpressure/volume characteristics of this operating rangeat the fan discharge shall be as indicated. Electric orpneumatic control actuators shall be used asindicated.

3.2.15 Spring-return actuators used for fan guidevane control shall open or close the guide vanes asindicated on control power failure.

3.2.16 Guide vane assemblies having vanes rotatedby lever arms connected to an external link ring shallnot be used where automatic control is required.

3.2.17 The guide vane operating mechanism shallproduce a nominally proportional relationship betweenchanges in system air volume and changes in controlactuator spindle movement. Where non-linearity oflinkage movement is used to approximate this effect,the relationship shall be stated and be approved bythe PM before installation.

20 October 1997



3.3 AXIAL FLOW FANS

3.3.1 Fan casings shall be rigidly constructed ofmild steel protected against corrosion or aluminiumalloy and shall be stiffened and braced wherenecessary to minimise drumming and vibration.Casings shall be fully airtight and flanged at eachend. Mounting feet shall be provided where necessaryfor bolting to a base or supports. For in-ductmounting, the length of the fan casing shall be greaterthan the combined length of the impeller(s) andmotor(s). Electrical connections to the motors shall bethrough flexible conduit to an external galvanisedmild steel or plastics terminal box secured to thecasing.

3.3.2 Provision shall be made for inspection of thefan impeller and motor. A removable inspection panelincorporating an air seal shall be fitted to casings450mm diameter and above.

3.3.3 Impellers shall be of mild steel protectedagainst corrosion, aluminium or moulded reinforcedplastics. The blades shall be securely fixed to the hub.Alternatively, the blades and the hub shall be formedin one piece. The hub shall be securely fixed to theshaft. Blades shall be of aerofoil section and whereindicated shall be capable of pitch adjustment.

3.3.4 Drive motors for axial flow fans of thebifurcated type shall be located out of the airstream.Casings shall be of the same thickness throughoutunless otherwise indicated, and shall extend for theoverall length of the impeller, hub, and motorprotection tunnel where applicable, and have circularflanged ends. Casings shall be mild steel withcontinuously welded joints and be lined or finished asindicated. The impeller shaft shall have a seal at thetunnel wall to prevent leakage in either directionbetween the motor tunnel and the fan interior.

3.3.5 For variable pitch bladed fans, the variablepitch mechanism and the indicated type of controlactuator shall be supplied by the fan manufacturer.The pitch of all blades shall be varied simultaneouslyand the difference in pitch between any two bladesthroughout the operating range shall not be greaterthan 0.5 degree. The total backlash between actuatorand blades shall not exceed 0.5 degree.

3.3.6 The variable pitch mechanism and controlactuator shall give fully modulated control of the fanair volume rate to match the system characteristic asindicated.

3.3.7 Spring-return actuators used for fan bladepitch control shall turn the blades to maximum orminimum pitch as indicated on control power failure.

3.4 IN-LINE CENTRIFUGAL AND MIXED FLOW FANS

3.4.1 Fan casings shall be rigidly constructed ofmild steel protected against corrosion or aluminiumalloy and shall be stiffened and braced wherenecessary to minimise drumming and vibration.Mounting feet shall be provided where necessary forbolting to a base or supports. Each inlet and outletshall terminate in a flange to BS 6339 to facilitateremoval. Stator vanes shall be of mild steel oraluminium alloy.

3.4.2 Provision shall be made for inspection of thefan impeller and motor. Casings shall have an accesspanel incorporating an air seal to facilitate cleaningand maintenance. A removable inspection panelincorporating an air seal shall be fitted to casings450mm diameter and above.

3.4.3 Fans connected at both ends to ductedsystems shall have circular cross section casings whichcover the overall length of the impeller, impeller hub,motor and any inlet cones and discharge straighteningvanes.

3.4.4 Impellers shall be mild steel protectedagainst corrosion or aluminium with blades welded orriveted to the impeller hub and shroud. Impellers withan outside diameter 500mm or less may be die-castaluminium with a fitted shroud.

3.4.5 Electrical connections to fans with direct-drive motors or motors mounted inside the casing,shall be through flexible conduit to an externalgalvanised mild steel or plastics terminal box securedto the fan casing.

3.4.6 Fans driven by externally mounted motorsshall have twin ball or roller bearing mounted steelimpeller shafts. The drives shall be so arranged tominimise air leakage and allow access to pulleys andbelts.

3.5 PROPELLER FANS

3.5.1 Propeller fans shall be ring mounted ordiaphragm mounted as indicated. Impellers shall be ofmild steel protected against corrosion, aluminium orplastics. The blades shall be securely fixed to the hub.Alternatively, the hub and blades shall be formed inone piece. Shafts shall be fitted with lipped slingerrings shaped to suit the fan mounting attitude.Vertical-shaft fans, with the impeller mounted above

October 1997 21



the motor, shall be fitted with an impeller spinnerwith a watertight seal against the motor shaft.

3.6 MECHANICAL ROOF EXTRACT UNITS

3.6.1 The fans used in roof extract units shallmeet the appropriate requirements of the precedingclauses relating to fans generally and to particulartypes of fans. Cowls and bases shall be of materialswhich are resistant to the weather and solar radiation,and which are appropriate to the location of the fan.Casings shall be complete with integralweatherproofing provisions suitable for direct fixing tothe building structure in accordance with themanufacturer's instructions. Adequate access toelectrical supply terminals and lubrication points shallbe provided by means of hinged cowls or otherwise asappropriate. Backdraught dampers and/or fire releasedampers shall be provided where indicated.

3.7 PACKAGED DUPLICATE-FAN EXTRACT UNITS

3.7.1 The housings of packaged units shallcontain all components of the unit except the terminalbox for electrical connections. The housing shall beprovided with dust-protected access covers to BS EN60529, for inspection and replacement of allcomponents. No electrical component shall be fixed toor supported by any access cover. A galvanised mildsteel terminal box shall be securely fixed to theoutside of the casing in a suitable position. Units to belocated in plant rooms may be supplied in chassisform, where indicated. Unless otherwise indicated, thefans shall be arranged for automatic change-over.

3.7.2 Housings and cowls of externally-mountedunits shall be weatherproof and manufactured fromgalvanised mild steel or aluminium alloy sheets, orglass reinforced plastics to BS 3532, assembled withcompatible and non-corroding nuts, bolts, washers andancillary items.

3.7.3 Discharge outlets shall be weatherproof andinclude guard screens to BS EN 60529: 1992, toprevent finger contact with electrical and movingparts. Each fan damper shall close when the fan is de-energised. All items shall have a non-corroding finish.

3.7.4 Unless otherwise indicated, dual fans andmotors shall be fitted on a common baseplatesupported on anti-vibration mountings.

3.7.5 Backdraught dampers shall have edge sealsand shall open and close fully. All blades shall bemechanically linked and shall close by gravity or lightsprings and be galvanised mild steel unless otherwiseindicated.

3.7.6 Fan failure in units consuming less than500W at the fan shaft shall be sensed and indicatedfrom switches operated by damper blade movement,unless otherwise indicated. Double-throw air flowswitches shall be used in units consuming more than500W at the fan shaft.

3.8 PROTECTIVELY—COATED FANS AND FANS FORCORROSIVE OR HAZARDOUS APPLICATIONS

3.8.1 Where fans are required to handle toxic,corrosive, flammable, explosive or high temperaturegases, the materials of construction shall be asindicated and all relevant safety regulations shallapply.

3.8.2 Bearing and lubrication arrangements andelectrical equipment shall be suitable for theconditions. Protectively coated fans shall meet theappropriate requirements of the preceding clausesrelating to fans generally and to particular types offans. The form of protection shall be as indicated.Where a protective coating is required for use withcorrosive gases, the coating shall fully cover all partsof the complete fan, motor and casing assembly whichwill be in contact with the corrosive gases. No fanshall be installed if the protective coating has beendamaged in any way. Subject to agreement with thePM, damage to coating may be repaired and offeredfor acceptance. Impellers shall be of coated steel,stainless steel, aluminium or plastics as indicated.Where fans are installed in a potentially explosiveatmosphere, the requirements shall be as indicated.

22 October 1997


Section Four—Air Filters

4.1 GENERAL

4.1.1 Filter assemblies shall operate with not lessthan the efficiencies or values of arrestance specifiedfor individual cells.

4.1.2 Filter material or wetting agents shall notbe carried over in the airstream.

4.1.3 Adequate access shall be provided forremoval and refitting of filter cells and replacement ofgaskets in filter holding frames.

4.1.4 Unless otherwise indicated, filters arrangedfor side withdrawal shall not be used.

4.1.5 Filter differential pressure indication shallbe provided for each filter assembly as described inSection Twenty-Two—Instruments—of thisSpecification.

4.2 FILTER CELL HOLDING FRAMES, SEALS ANDGASKETS

4.2.1 Filter cell holding frames shall be purpose-made from non-ferrous metal, plastic, or steelprotected against corrosion, of adequate strength andstiffened as required to prevent distortion in use.

4.2.2 Holding-down frames shall be capable ofretaining air filters, constructed within thedimensional tolerances stated, in a rigid manner andwithout edge leakage.

4.2.3 The entire framework shall be securely fixedin position with all edges and joints effectively sealedto prevent air leakage.

4.2.4 Purpose-made gaskets shall be provided tominimise air leakage around the filters. Theeffectiveness of the seal shall not be impaired byremoval and refitting of filter cells. Gasket materialshall be fitted in the holding frames except in the caseof holding frames for HEPA type filters where therequirements of Clauses 4.8.3 and 4.8.4 shall apply.

4.2.5 The retaining clips, or other securing device,shall be capable of pulling the filter on to its seatingand shall exert equal pressure on all faces.

4.2.6 For HEPA type filters in side withdrawalframes, retention shall be by over-centre camoperation with pressure adjustment. Holding-downbolts are acceptable where adequate access isprovided.

4.3 FIRE PROPERTIES

4.3.1 Filter media (other than for adsorptionfilters), all materials of construction, adhesives,coatings and wetting agents shall permanently retainself-extinguishing properties.

4.3.2 When exposed to heat or flame, the filtershall not generate significant quantities of smoke ortoxic fumes into the airstream. In no case shall thetotal toxic vapour emission into the airstream,calculated over a period of 10 minutes, result in the 10minute exposure level of any toxic constituent, (asgiven in the current Health and Safety ExecutiveGuidance Note EH 40), being exceeded.

4.3.3 Where flameproof filters are indicated, theframes, casings and filter cell holding frames shall beclassified non-combustible when tested in accordancewith BS 476: Part 4.

4.4 PERFORMANCE CERTIFICATION

4.4.1 A copy of the type test certificate, issued bya NAMAS accredited air filter testing laboratory, shallbe submitted for each type of filter offered.

4.4.2 Filters of the extended surface type andpanel type shall be tested in accordance with BS EN779. The certificate shall indicate the results of a testconducted on filters with a nominal face area 600mmx 600mm and at a face velocity of 2.5m/s or 1.75m/sas required under the relevant clauses of thisSpecification.

October 1997 23



4.4.3 Filters with an initial atmospheric dust spotefficiency exceeding 98% are not covered by BS EN 779.If initial atmospheric dust spot efficiency is less than20%, filter is classified as a group G filter.

4.4.4 HEPA filters shall be tested in accordancewith BS 3928.

a) For filters of 99% efficiency and above, eachfilter shall be individually tested.

b) Random tests for filters below 99% efficiencywill be accepted. A minimum sample of 10%(minimum one filter), of each size andefficiency shall be tested.

Test certificates for all units shall be submitted to thePM.

4.4.5 At the discretion of the PM, two samples ofany filter intended for use shall be selected by him atrandom for test to the standards specified.

4.5 FILTER GRADES

4.5.1 Where filters are specified in terms of aFilter Class, this relates to average atmospheric dustspot efficiency or average synthetic dust weightarrestance in accordance with BS EN 779. The gradefor any particular class of filter applies to air volume,dust holding capacity and final resistance as stated inthis Specification.

4.6 BAG OR EXTENDED SURFACE TYPE FILTERS

4.6.12.5m/s.

Air velocity at the filter face shall not exceed

4.6.2 Filters shall be fully self-supporting withoutexternal ties or stiffening frames. Filters shall inflatefully, shall not sag or flutter, nor have effectivemedium area reduced by obstruction due to contactwith other filter faces or housing surfaces whenoperating between 60% and 110% of design air volumeflow rate for fixed volume systems, or between theindicated minimum and maximum air volume flowrates for VAV systems.

4.6.3 The following face dimensions shall apply:

4.6.4 The dust holding capacity, as achieved bytests carried out on 595mm x 595mm air filters at anair volume flow rate of 0.94m3/s, shall comply with thefollowing:

Class 3 filters; Not less than 500g at 250 Pafinal resistance






4.6.5 Unless otherwise indicated, pre-filters of thistype shall conform to Class 3 and main filters to Class 5.

4.6.6 A set of spare filters shall be provided tocompletely replace each filter assembly and shall notbe fitted without the prior approval of the PM.

4.7 PANEL FILTERS

4.7.1 Air velocity at the filter face shall not exceed1.75m/s.

4.7.2 Cardboard filter casings shall be treated foruse in conditions up to 80% saturation and shall beadequately stiffened to prevent distortion in handling.

4.7.3 Where filter pads in permanent casings orframes are provided, the pads shall be limited to therequirements for Grade 2 filters. Pads shall complywith all requirements for replaceable type panelfilters. Frames shall conform to the dimensions givenin Clause 4.7.4.

4.7.4 The following face dimensions shall apply:

Class 2 and Class 3 filters;

24 October 1997



4.7.5 The dust holding capacity, as achieved bytests carried out on 595mm x 595mm air filters at aface velocity of 1.75 m/s, shall comply with thefollowing:

Class 2 filters: Not less than 275g at 170 Pafinal resistance

Class 3 filters: Not less than 250g at 170 Pafinal resistance

Class 4 filters: Not less than 300g at 250 Pafinal resistance.

4.7.6 The filters shall conform to the classes asindicated.

4.7.7 A set of spare filters shall be provided tocompletely replace each filter assembly and shall notbe fitted without the prior approval of the PM.

4.8 HIGH EFFICIENCY PARTICULATE AIR (HEPA)FILTERS

4.8.1 HEPA filters and filters of HEPA typeconstruction shall consist of pleated glass paper orother approved medium sealed within a rigidlyconstructed case.

4.8.2 The air filter casing filter medium,protective cappings and sealing gaskets shall be ofmaterials compatible with the temperature, humidityor corrosive conditions indicated. The casing shall notwarp, splinter or corrode.

4.8.3 Unless otherwise indicated, a 6mm thickgasket shall be fitted to the downstream face of thefilter. The gasket shall be of one-piece mouldedconstruction or with all joints sealed to ensure apositive air seal through the filter life.

4.8.4 Before any filter is fitted into its holdingframe, the gasket shall be lubricated to preventsubsequent adhesion to its mating face. The lubricantshall be compatible with the gasket and mating facematerials.

4.8.5 Test groove seals shall be incorporatedwhere indicated.

4.8.6 Where indicated, completed installationsusing HEPA filters shall be tested as part of finalcommissioning. The test shall be carried out by acompetent specialist, acting for the Contractor,approved by the PM. The test shall be conducted usingDOP, sodium flame or other method approved by thePM. During the entire test period, design air flow rate

conditions shall be maintained to within the specifiedlimits. On completion of satisfactory testing, a testcertificate shall be issued.

4.9 ACTIVATED CARBON AND ADSORPTION FILTERS

4.9.1 Adsorption filters shall comprise panels orbeds containing adsorbent medium evenly dispersedand assembled into a casing. The panels shall besealed effectively against air leakage. Casing andpanel supports shall be constructed from metaladequately protected against corrosion and shall bedesigned to provide mechanical protection to thepanels. Filter frames and adsorbent medium retainingmesh shall be of non-combustible materials.

4.9.2 The adsorbent beds in the filter shall be ofuniform thickness, packed to ensure that compactionor voids do not occur in use. Alternatively, adsorbentbeds where a bonding agent is used to join adjacentgranules may be used provided that the conditions forefficiency, adsorption capacity and air flow resistanceas indicated are achieved.

4.9.3 The resistance to air flow shall not exceed125 Pa at the design air volume flow rate.

4.9.4 Each filter assembly shall include twodetachable test sections for use in predicting theservice life of the filter assembly. These test sectionsshall be exposed to full air flow and be removed andreplaced by a spare after 6 and 12 months operationand returned to the manufacturer for analysis ofsaturation and report on service life remaining. TheContractor shall be responsible for this removal andreplacement during the defects liability period andshall include for the spares, the manufacturer's costsfor the analysis/report and for passing these to thePM. The test sections shall be approximately 150mm x150mm or equivalent area and be of equal thickness tothe adsorbent beds in the filter. Allowance shall bemade for housing these test sections as part of thefilter assembly.

4.9.5 For general odour removal where particularcontaminants are not specified, unimpregnatedactivated carbon having a hardness factor of not lessthan 97% (ASTM 3802-79 (1990)) shall be used. Aminimum of 80 litres net of activated carbon, orsufficient to adsorb not less than 20kg of CC14 basedon test procedures in accordance with ASTM 3467-76(1993), shall be provided for each 1.0 m3/s of designair volume flow rate.

4.9.6 Where particular contaminants areindicated, the adsorbent shall be provided to such aquality and bed depth as to achieve the permitted

October 1997 25



maximum concentration level in the air flow leavingthe filter bed. Evidence as to both efficiency andadsorption capacity of the adsorbent at the indicatedlevels shall be submitted to the PM for acceptance.

4.9.7 Activated carbon filters shall be preceded bya dry fabric extended surface type filter of not lessthan Class 5.

4.10 GREASE ELIMINATORS

4.10.1 Grease eliminators shall be of thecorrugated plate type, crimped wire mesh type orbaffle type and be entirely of metal. All materials usedshall be resistant to or protected against corrosion.Where grease eliminators are fitted in kitchen hoods,the assembly shall include a drip tray and the elementshall be secured in the frame by quick-release clips.

4.10.2 In all cases the grease eliminator shall bereadily accessible and removable for cleaning.

26 October 1997



TABLE 4A: FILTER CLASSESThe following filter classes shall apply:

Initial dust spot efficiency (EA)<20%Initial dust spot efficiency (EA)$20%

October 1997 27


Section Five—Air Heater and Cooler Batteries

5.1 GENERAL

5.1.1 Air heater and cooler battery design shallensure equal fluid flow through all battery circuits. Allwater batteries shall be arranged in contraflow withthe water entering at the air leaving end and leavingat the air entering end. The flow and return batteryconnections shall be labelled and the air flow directionshall be indelibly marked on the battery casing.Unless otherwise indicated batteries shall be eightrows maximum depth.

5.1.2 Heat exchanger finned surfaces shall extendfor the full width of the battery casing except wherebaffles, suitably protected against corrosion, areprovided to prevent air by-passing the finned surface.Sealing devices shall be fitted to tops and bottoms ofbatteries to prevent air by-pass and water carry-over.

5.1.3 Fins shall make firm and continuous contactwith the primary tubes. Where more than one primarytube is required, tube rows shall be staggered in thedirection of air flow to maximise heat transfer andprovide even air distribution across the face of thebattery.

5.1.4 Heater batteries shall be constructed fromone of the following material combinations asindicated:

a) Copper tubes with aluminium or copper finsand copper or steel headers.

b) Mild steel tubes with mild steel fins and steelheaders, all corrosion protected.

c) Cupro-nickel tubes with aluminium or copperfins and cupro-nickel or steel headers.

5.1.5 Chilled water cooler battery materials shallbe selected to minimise electrolytic action, suitable forthe operating conditions and constructed from one ofthe following combinations as indicated:

a) Copper tubes with aluminium fins and copperor steel headers.

b) Copper tubes with copper fins and copper orsteel headers.

c) Tinned copper tubes with aluminium fins andcopper or steel headers.

d) Copper tubes with copper fins electro-tinnedin block form after assembly and copper orsteel headers.

e) Cupro-nickel tubes with aluminium or copperfins electro-tinned in block form afterassembly and cupro-nickel or steel headers.

5.1.6 Direct-expansion refrigerant cooler batterymaterials shall be selected to minimise electrolyticaction, suitable for the operating conditions andconstructed from one of the following combinations asindicated and shall be suitable for the particularrefrigerant to be used:

a) Tinned copper tubes with aluminium fins andcopper headers.

b) Copper tubes with copper fins electro-tinnedin block form after assembly and copperheaders.

5.1.7 Where indicated vinyl coated aluminium finsor epoxy coated aluminium fins are permitted forheater batteries, chilled water batteries or directexpansion cooler batteries.

5.1.8 Copper and cupro-nickel tubes shall complywith BS 2871: Part 3. Tubes shall be of 0.71mm(minimum) wall thickness with bends and returnbends of 0.91mm wall thickness. Tubes for highpressure applications (greater than 10 bar gaugepressure) shall be of 0.91mm wall thickness. Electro-tinning shall comply with the requirements of BS1872. Unless otherwise indicated fins shall be ofsmooth plain 0.25 mm copper. For dehumidifying coilsfins shall be not more than 300 per metre. Fin spacingfor sensible cooling only batteries and heatingbatteries shall be 300 per metre or as indicated. In

28 October 1997



order not to impede air flow, all fins shall be capableof being properly straightened before commissioning.Copper headers shall have formed sockets for primarytube jointing and BSP male thread, or flangedconnection. Mild steel tube shall comply with BS 1387.

5.1.9 Casings shall be of sheet steel galvanisedafter manufacture not less than 1.2mm thick withflanges at each end drilled to match connectingductwork or other associated equipment.

5.1.10 Headers and return bends located outsidethe casing shall be enclosed in removable gaskettedairtight covers profiled to suit the pipe connections toheaders, be close-fitting and reinforced at suchopenings to locate a flexible sealing ring. All jointsshall be sealed. Connections shall terminate 100mmminimum clear of the covers with disconnection jointspositioned to permit full withdrawal and removal ofbatteries without dismantling adjacent piping,ductwork or other equipment. The removable coversshall be lined with 19mm thickness flexible thermalinsulation.

5.1.11 Header connections on low and mediumtemperature hot water heater batteries and chilledwater cooler batteries shall be screwed to BS 21 up toand including 50mm size and flanged to BS 4504 for65mm size and above. Screwed connections shall bemade using ground-in spherical seated unions.

5.1.12 Header connections on high temperature hotwater and steam heater batteries shall be flanged toBS 4504 for all sizes.

5.1.13 For steam and water batteries, isolatingvalves shall be provided on the inlet and outletconnections arranged to facilitate removal of thebattery. All water batteries shall have a means ofventing and draining. Steam batteries shall have anair release tapping.

5.1.14 Unless otherwise indicated, accessibletemperature sensor pockets shall be provided to allflow and return headers for monitoring purposes.

5.1.15 Anti-frost heaters fitted in fresh air intakesshall have plain tubing or tubing with widely spacedfins at not less than 6mm pitch and shall offerminimum resistance to air flow consistent withachieving the required heat transfer. Steam heaterbatteries, where used as anti-frost heaters, shall haveperforated internal tubes to distribute steam evenlythroughout the host tubes to ensure that condensatewill not freeze.

5.1.16 Batteries shall be supported so that theirweight is not transmitted to ductwork or pipeworkand so that removal can be achieved withoutdisturbing adjacent ductwork and other services.

5.1.17 Access openings shall be provided inaccordance with Section Eight—Ductwork, Dampersand Terminal Devices—of this Specification.

5.1.18 Self-sealing test points, in accordance withSection Fourteen—Pipework—of this Specification,shall be provided on the inlet and outlet connectionsto each water battery.

5.2 TESTS

5.2.1 Battery design and sizing shall be based onfigures obtained from performance tests described inBS 5141: Part 1 for cooling and heating coils.

5.2.2 All batteries shall be tested before leavingthe manufacturer's works. A test certificate shall beissued for each battery or each battery shall beindelibly marked with the details of the test.

5.2.3 Each water battery shall be tested for leaksby using air under water to 1.5 times the workingpressure or 8 bar gauge pressure whichever is greaterfor 30 minutes.

5.2.4 Each steam heater battery shall be hotsoaked for 1 hour followed by live steam purged for 30minutes at a minimum pressure of 140 mbar gaugeand then tested for leaks by using air under water asfor water batteries in Clause 5.2.3.

5.2.5 Each direction-expansion refrigerant coolerbattery shall be tested for leaks by using air underwater to 19 bar gauge pressure for 30 minutes.

5.3 HOT WATER HEATER BATTERIES

5.3.1 Heat exchangers shall have horizontalprimary tubes, vertical fins and vertical headers.

5.3.2 Tube wall thicknesses and batteryconstruction shall be suitable for the system operatingpressures and temperatures.

5.3.3 Tubes shall terminate in one pair of tubularheaders for each battery or battery section.

5.3.4 The resistance to air flow through thebattery shall not exceed 65 Pa and the face velocityshall not exceed 4m/s. Resistance to air flow for run-around coils and batteries supplied with low gradeheat shall not exceed 150 Pa.

October 1997 29



5.4 STEAM HEATER BATTERIES

5.4.1 Heat exchangers shall have vertical primarytubes, horizontal fins and horizontal headers.

5.4.2 Tube wall thicknesses and batteryconstruction shall be suitable for the system operatingpressures and temperatures. Batteries operating inexcess of 10 bar gauge pressure or 200°C shall havecupro-nickel tubes and headers.

5.4.3 Tubes shall terminate in one pair of tubularheaders for each battery or battery section.

5.4.4 Vacuum breakers shall be fitted to allbatteries.

5.4.5 A steam trap set as prescribed in DEOSpecification 036 shall be provided for each battery orbattery section.

5.4.6 The resistance to air flow through thebattery shall not exceed 65 Pa and the face velocityshall not exceed 4m/s.

5.5 ELECTRICAL HEATER BATTERIES

5.5.1 Electrical heater batteries shall consist of anumber of heating elements of the enclosed typemounted in a sheet steel casing. Elements shall be soarranged to permit removal without dismantlingductwork.

5.5.2 The connections from each element shall beextended to a terminal box housed in an accessibleposition with conduit entry provision.

5.5.3 Each heater section shall be separately fusedand the neutral point for all three-phase star-connectedsections brought out to a link in the terminal box.

5.5.4 In the proximity of hot areas, the electricalwiring insulation shall be suitable for the maximumtemperature.

5.5.5 The surface temperature of the elementsshall not exceed 400°C when measured in an air flowof 2.5m/s at ambient temperature.

5.5.6 Each electrical heater battery shall be suppliedcomplete with a manually reset thermal cut-out of thethree-contact type to provide an audible or visual alarmsignal on high temperature cut-out as indicated. The cut-out sensor shall be nearest to and above the heatingelements energised by the first control step.

5.5.7 An isolator and a hazard warning sign whichclearly indicates the operating voltage, shall be fittedimmediately adjacent to the heater access opening.

5.5.8 Unless otherwise indicated, the control ofelectrical heater batteries except for remote boosters,shall be interlocked with the system fan motor starterand an air flow sensing device of the vane or pressuretype to ensure that the heater operates only when thefan is running and air flow is established.

5.5.9 Electrical heater batteries which areinstalled as boosters in branch ducts, shall each havea local air flow sensing device of the vane or pressuretype to ensure that the heater operates when air flowis established.

5.5.10 The number of elements in the heater shall bethe same as or a multiple of the number of steps in thecontroller. All heaters and heater sections of more than3kW loading shall be balanced over three phases and thecomplete heater bank shall be arranged for balancedoperation on a three-phase, four-wire system.

5.5.11 The resistance to the air flow through thebattery shall not exceed 25 Pa and the face velocityshall not exceed 6m/s nor be less than 2m/s.

5.6 CHILLED WATER COOLER BATTERIES

5.6.1 Heat exchangers shall have horizontalprimary tubes, vertical fins and vertical headers.

5.6.2 The bottoms of casings shall be made in theform of a watertight drain tray from sheet steelgalvanised after manufacture, or be otherwise equallycorrosion resistant. Eliminator sections shall beprovided. The drain tray serving the cooler shall beextended or a separate tray shall be provided to collectwater from the eliminator. Drain trays shall be slopedtowards a flush drain connection so that no water isretained in the drain tray. A pipework drainconnection, complete with quick-release refillable trap,shall be extended from the lowest point on theunderside of the tray to the nearest sump or gully todischarge through an air break. A water seal ofsufficient depth shall be provided to prevent entry orexit of air to or from the system and additionallymaintain a 75mm seal when the plant is de-energised.The distance between the underside of the tray andthe crown of its trap is to be sufficient to ensure thetray is fully drained during operating periods.

5.6.3 Intermediate drain trays shall be providedwhere the battery height exceeds 950mm. The generalarrangement shall ensure that collected water isdrained towards one end of the tray and through the

30 October 1997



lowest point in the tray to the lower tray, via a downpipe, without splashing. Further drain trays shall beprovided for each additional 950mm of battery height.

5.6.4 Eliminator sections shall be positioned toavoid damage from adjacent heater batteries and shallbe of materials unaffected by such heat.

5.6.5 The total resistance to air flow through thebattery and eliminator sections shall not exceed 240Pa under wet coil conditions. The face velocity shallnot exceed 2.5m/s and point velocity shall not exceed3m/s.

5.7 DIRECT-EXPANSION REFRIGERANT COOLERBATTERIES

5.7.1 Coolers shall be provided with inlet liquiddistributors and return suction headers arranged toensure even distribution of refrigerant to all circuits

and to return oil to the compressor. The tubes shall bestaggered in the direction of air flow. Liquiddistributors, return suction headers and return bendsshall be located out of the airstream.

5.7.2 All circuits shall have an even number oftubes to ensure that liquid and suction connectionsare on the same side.

5.7.3 Drain trays, pipework drain connections,traps and eliminator sections shall be provided inaccordance with Clauses 5.6.2 to 5.6.4.

5.7.4 On satisfactory completion of allmanufacturer's works tests, batteries shall bedehydrated, charged with a dry inert gas and sealed.

5.7.5 The total resistance to air flow through thebattery and eliminator sections shall not exceed 240Pa under wet coil conditions. The face velocity shallnot exceed 2.5m/s and point velocity shall not exceed3m/s.

October 1997 31


Section Six—Air Washing and Humidifying Plant

6.1 GENERAL

6.1.1 All ductwork and casings enclosinghumidifying plant shall be air and watertight.Ductwork, plant and components shall be protectedfrom corrosion either by choice of materials or by anapproved protective finish. Particular care shall betaken in the design of plant and the choice ofmaterials to minimise electro-chemical reactionbetween dissimilar metals.

6.1.2 A sealed inspection door shall be providedon the downstream side of equipment mounted inductwork.

6.1.3 Humidifying units shall be complete with allnecessary devices for fixing to ductwork sides orsupporting from adjacent walls or from the floor asindicated.

6.1.4 Injection pipes for introduction of dry steamfrom the unit into the airstream shall be fabricated inGrade 304 stainless steel.

6.1.5 All materials of construction used inhumidifying equipment shall be suitable for cleaningand disinfection with concentrated chlorine andsimilar chemical solutions.

6.1.6 Unless otherwise indicated, the control ofhumidifying plant shall be interlocked with the systemfan motor starter and a local air flow sensing device ofthe vane or pressure type to ensure that thehumidifying plant operates only when the fan isrunning and full air flow in the washing orhumidifying section is established.

6.2 STEAM HUMIDIFIERS

6.2.1 General

6.2.1.1 Steam humidifiers shall have immersionelements of the electrical, steam or HTHW type, or beelectrode boiler type, or be direct steam injection typeas indicated.

6.2.1.2 Steam injection equipment arrangementsshall ensure that only dry steam is delivered into theairstream.

6.2.1.3 Means of electrical isolation of self-generative steam humidifiers shall be arranged tofacilitate removal of the elements/electrodes formaintenance and replacement.

6.2.1.4 Electrical heating elements shall incorporatea high temperature cut-out which shall be interlockedwith the water level control to de-energise theelectrical circuit on low water level.

6.2.1.5 Electrical components shall comply with therequirements of DEO Specification 034.A comprehensive wiring diagram shall be fitted in theelectrical compartment encapsulated in a sealed clearplastic cover.

6.2.1.6 Self-generative steam humidifiers for directconnection to water supplies shall be Water ResearchCouncil approved.

6.2.2 STEAM HUMIDIFIERS—DIRECT INJECTION TYPE

6.2.2.1 The unit shall comprise separation chamber,modulating valve, drying chamber and distributionmanifold complete with steam jacket. The unit shallbe complete with:

a) steam stop valve and strainer fitted to thesteam inlet connection,

b) scale pocket, float trap complete withautomatic air vent, and isolating valveconnected to separation chamber,

c) steam distribution pipe, designed andinstalled to incorporate condensate return andensure free moisture is not carried over intothe airstream.

32 October 1997



6.2.3 SELF-GENERATIVE STEAM HUMIDIFIERS-GENERAL

6.2.3.1 Packaged steam humidifiers shall compriseintegral cold water supply tank, evaporation chamber,heating elements/electrodes and controls, all mountedon a mild steel framework enclosed within anenamelled or galvanised mild steel casing lined withapproved slab insulation.

6.2.3.2 Internal surfaces and fittings shall be ofnon-corrodible materials. The cold water tank shall becomplete with a level control valve, overflowconnection, water level gauge and pressure equalisingpipe. The evaporation chamber of immersion heatertype units shall have an inspection cover and shall befully drainable.

6.2.3.3 An integral automatic time-controlledflushdown set, with copper drain pipework, shall beprovided.

6.2.4 SELF-GENERATIVE STEAM HUMIDIFIERS-ELECTRICAL IMMERSION HEATER TYPE

6.2.4.1 The evaporation chamber shall containcopper sheathed resistance type heating elementssuitable for solid-state modulating controls mountedon a detachable plate.

6.2.4.2 Control equipment shall be pre-wired withterminal block, low water level cut-out, controlled pilotheater, indicator lamps, controls fuse and neutral linkand provision for humidistat connection all housed inan accessible electrical compartment within the unitcasing.

6.2.5 SELF-GENERATIVE STEAM HUMIDIFIERS-ELECTRODE BOILER TYPE

6.2.5.1 Electrode boiler steam humidifiers shallhave separate steam and control compartmentsformed in one enamelled steel casing with lockabledoors. Steam generating cylinders shall contain theheating electrodes and shall have a steam outlet hoseconnecting to the duct steam injection pipe.

6.2.5.2 Where located within the airstream, steamgenerating cylinders shall be constructed of non-flammable materials. Units shall 'fail-safe' in theevent of interruption of power or water supplies. Aspare cylinder shall be provided with each unit.

6.2.5.3 Automatic emptying of steam generatingcylinders shall be pump assisted.

6.2.5.4 Units shall be pre-wired internally with theterminals for incoming power and control circuitconnections. A full height access opening shallincorporate indicator lamps and switches. Controlmethods that employ draining or refilling of the steamgenerating cylinder to achieve variations in steamoutput will not be permitted.

6.2.6 SELF-GENERATIVE STEAM HUMIDIFIERS—STEAMOR HTHW IMMERSION HEATER TYPE

6.2.6.1 The evaporation chamber shall contain asteam or HTHW heating coil fitted into a waterreservoir.

6.2.6.2 Heating coils shall be of solid-drawn coppertube mounted on a detachable plate.

6.2.6.3 Steam heated coils shall have screwed endsfor connections to steam and condensate servicebranches.

6.2.6.4 HTHW heated coils shall have flangedconnections.

6.3 ULTRA-SONIC TYPE HUMIDIFIERS

6.3.1 Where indicated, humidifiers of the ultra-sonic type shall be supplied with demineralised wateronly.

6.3.2 The water reservoir shall be of 1.2mmthickness, Grade 304 stainless steel.

6.3.3 Electronic and electrical components shall becapable of continuous operations.

6.3.4 Duct-mounted units shall have a clear,straight duct length of 500mm downstream. The air-stream velocity at the point of installation shall notexceed 3m/s.

6.3.5 Units shall be provided with a humidistatand an electrical isolating switch.

6.4 DRAINAGE

6.4.1 All non-storage humidifiers shall beprovided with a pipework drain connection, completewith quick-release refillable trap, extended from thelowest point of the humidifier casing to the nearestsump or gulley to discharge through an air break. Awater seal of sufficient depth shall be provided toprevent entry or exit of air to and from the systemand additionally maintain a 75mm seal when theplant is de-energised. The distance between the

October 1997 33



underside of the humidifier and the crown of its trapshall be sufficient to ensure the casing can be fullydrained.

34 October 1997


Section Seven—Air Handling Units

7.1 GENERAL

7.1.1 'Air Handling Unit' (AHU) shall mean anassembly of packaged plant components. Eachcomponent shall be incorporated within a single-skincasing or double-skin casing as indicated. Casingsshall generally be of constant cross-sectionaldimensions. Casings shall be complete internal flangedjoints. Mixing sections, with fresh and re-circulatedair connections complete with dampers as appropriate,shall be included together with access sections,bulkhead light fittings and viewing panels. Packagedplant components shall comprise a combination of thefollowing: fans, filters, heaters, coolers, humidifiersand attenuators, all as described elsewhere in thisSpecification. NOTE: Air handling plant componentsmay also be duct-mounted remote from the AHU.

7.1.2 Individual components shall, in addition tothe requirements of this section, comply with otherrelevant sections of this Specification.

7.2 CONSTRUCTION

7.2.1 AHUs shall be of rigid construction tominimise distortion and drumming in operation, andshall be no less rigid in construction than thedistribution ductwork to which they are connected.

7.2.2 AHUs shall be corrosion resistant.

7.2.3 Jointing methods shall ensure that AHUsare not less airtight than the related ductwork system.

7.2.4 Individual components and sections shall beassembled using proprietary and proven fasteningtechniques. Locking devices shall be used with allfastenings which are subject to vibration.

7.2.5 Floor decking, suitable for 1.5kN/m2 loading,shall be provided to all accessible sections.

7.2.6 Each section shall be identified by a clearstencil description on the external surface.

7.2.7 Unless otherwise indicated, there shall be aclearance of at least 150mm between the underside ofthe AHU and its base or the plant room floor.

7.2.8 Unless otherwise indicated, AHUs shall beof double-skin construction incorporating thermalinsulation. The thermal insulation shall have athickness not less than 25mm and a thermalconductivity not greater than 0.03 W/mK. Hollowsection frame posts, where used, shall be insulated asfor the casing.

7.2.9 Mineral fibre insulation must not be usedwithin the AHU unless factory applied and containedwithin an impervious membrane designed to last thelife of the AHU.

7.2.10 Single-skin units shall be fabricated fromgalvanised mild steel sheet, or other approvedmaterial, in tray form.

7.2.11 Any surface liable to condensation formationshall be insulated and provided with a vapour barrierin accordance with Section Seventeen—ThermalInsulation—of this Specification.

7.2.12 Readily removable access panels or hingeddoors complying with Clause 21.3 of HVCASpecification DW/142, incorporating air seals shall beprovided to facilitate access to upstream anddownstream faces and internal parts of all sections inthe AHU. Access panels shall be secured with aminimum number of proprietary quick-release captivefastenings consistent with effective air sealing. Hingeddoors shall be retained with clamping type latches.Access panels and hinged doors shall be 500mm wideminimum and sized for the full height of the AHU orbe 1.35m maximum. Self-tapping screws and setscrews are not acceptable as panel fastening.

7.2.13 Sections of packaged AHUs shall bearranged with adequate separation to avoidevaporation of condensate from the cooler by theheater battery and generally to promote even airdistribution across the face of all components.

October 1997 35


Section Seven—Air Handling Units

7.2.14 AHUs incorporating humidifying plant and/or cooler batteries, having exposed metal surfaceslikely to be affected by moisture, shall be protected bya properly prepared and applied two-coat minimumpaint scheme or other approved finish to preventcorrosion. Galvanised mild steel shall be cleaned andpainted with two coats of approved bituminoussolution or shall receive other such internal treatmentas indicated. Protection shall extend 1m either side ofthe humidifier or cooler battery. Units shall havecorrosion-resistant drain trays of adequate size tocollect waste water, extended as necessary or othermeans of collection provided, to drain away any waterdeposited or condensed in adjacent sections. Draintrays, pipework drain connections and traps shall bearranged as described in Section Five—Air Heater andCooler Batteries—of this Specification. Where thedrain tray forms the outer surface of the AHU, theouter surface shall be insulated and vapour sealed.

7.3 THERMAL AND ACOUSTIC INSULATION

7.3.1 Thermal insulation shall be securely fixed toall sections handling heated or cooled air and a vapourbarrier shall be provided as appropriate. Thermal andacoustic insulation shall be in accordance with SectionSeventeen—Thermal Insulation, and Section Twenty-One—Vibration Isolation and Noise Isolation, of thisSpecification. Where free moisture may be present, awaterproof membrane shall be provided. Protectionshall be provided to avoid damage to insulation insections having walk-in access. For single-skin units,thermal insulation shall be closed-cell type and have athickness not less than 25mm and a thermalconductivity not greater than 0.03 W/m K.

7.4 DAMPERS

7.4.1 All dampers shall comply with SectionEight—Ductwork, Dampers and Terminal Devices ofthis Specification. Motorised dampers shall complyadditionally with Section Twenty-Three—AutomaticControls of this Specification.

7.5 FANS

7.5.1 AHU fans shall comply with therequirements of Section Three—Fans—of thisSpecification. Additionally, the fan section shall betested in accordance with BS 6583 and fan totalefficiencies shall be not less than 60% and 50% forbackward bladed and forward curved typesrespectively.

7.5.2 Unless otherwise indicated, each fan anddrive motor shall be mounted on a common frame orother means of support. The complete assembly shallbe isolated from the casing to prevent thetransmission of vibration. Electrical connections shallnot inhibit free movement of the fan and drive motorset.

7.5.3 Where the fan and drive motor are directlyconnected to the fan section casing, the casing shall beisolated from the structure to prevent transmission ofvibration. Flexible jointing to adjacent sections shallbe provided.

7.5.4 Where an externally-mounted drive motor isindicated, the fan impeller shaft shall extend throughan airtight gland seal in the casing. Flexible joints inaccordance with Section Eight—Ductwork, Dampersand Terminal Devices—of this Specification, andvibration isolators in accordance with Section Twenty-One—Vibration Isolation and Noise Insulation—of thisSpecification, shall be used to minimise thetransmission of vibration and noise.

7.5.5 All power transmission shafts, belts andpulley drives shall be guarded in accordance withSection Twenty—Belt Drives, Variable Speed Drivesand Guards—of this Specification.

7.6 PROVISIONS FOR AUTOMATIC CONTROLS,SENSORS, INSTRUMENTS AND TEST HOLES

7.6.1 Airtight sleeves shall be provided for controlsensors, instruments and test holes for the followingapplications:

a) double-skin units,

b) insulated single-skin units,

c) ducts insulated internally or externally.

7.6.2 Compartments housing control elementsshall comply with Section Twenty-Four—Starter andControl Panels—of this Specification.

7.7 OUTDOOR UNITS

7.7.1 AHUs for outdoor installation shall have aweatherproof outer casing, a pitched roof constructedof watertight metal decking with water seals in alljoints and lockable access doors.

7.7.2 Bulkhead light fittings shall be provided ineach section with a weatherproof external switch andall wiring in galvanised mild steel conduit.

36 October 1997

Specification 037 Section Seven—Air Handling UnitsAir conditioning, air cooling andmechanical ventilation for buildings

7.7.3 Thermal insulation shall be in accordancewith Section Seventeen—Thermal Insulation—of thisSpecification.

October 1997 37

Specification 037Air conditioning, air cooling andmechanical ventilation tor buildings

Section Eight—Ductwork, Dampers and TerminalDevices

8.1 FABRICATION DRAWINGS

8.1.1 The ductwork layout indicated is fortendering purposes only. All relevant dimensions areto be verified by the Contractor from site beforeductwork is manufactured unless otherwise agreed bythe PM.

8.2 SHEET METAL DUCTWORK

8.2.1 Ductwork materials and construction shallcomply with HVCA Specification DW/142 andAddendum A. The ductwork classification shall be asindicated.

8.2.2 Unless otherwise indicated ductwork shallbe delivered to site cleaned to 'Intermediate Level' toHVCA DW/TM2.

8.2.3 Site storage areas shall comply with HVCADW/TM2.

8.2.4 Unless otherwise indicated, the methods ofconstruction for seams and joints shall be inaccordance with HVCA Specification DW/142 andAddendum A.

8.2.5 Materials used for ductwork constructionshall be free from blisters, pits and surfaceimperfections.

8.2.6 Where indicated, all raw edges of ductworkand areas where galvanising has been destroyed shallbe cleaned, prepared and painted with zinc-rich paintat works.

8.2.7 Internal roughness and obstructions to airflow, (other than dampers, splitters, vanes, etc), willnot be accepted for ductwork constructed from sheetmaterials. Sharp edges or corners on the outside ofductwork, fittings and supports will not be accepted.

8.2.8 Perforated rivets shall not be used in themanufacture or erection of ductwork.

8.2.9 Ductwork connecting to or enclosing aflameproof air filter medium, shall be not less than1.6mm thickness for at least 1.8m upstream and 1.8mdownstream of the filter.

8.2.10used.

Square and 90 degree branches shall not be

8.2.11 Connection points for instruments andcontrols shall be reinforced to provide adequatesupport.

8.2.12 Bolted, gasketted, angle section flangedjoints shall be provided for dismantling whereindicated.

8.3 INSTALLATION

8.3.1 Ductwork supports shall be provided close todampers, diffusers, etc., in addition to those hangersand supports required for ductwork generally.

8.3.2 Duct connections between individualcomponents of air handling equipment, andconnections between equipment and ductwork, shallbe made with bolted, gasketted, angle section flangedjoints.

8.3.3 Flexible joints to fans shall be tightlyclamped to prevent air gaps and the material, whichshall have a fire penetration time of at least 15minutes when tested in accordance with BS 476: Part7 and Part 22, shall remain flexible and without strainor distortion.

8.3.4 At each point where a duct passes through aroof or external wall, a weather cravat or otherpurpose-made arrangement shall ensure weatherprooffixing.

38 October 1997


Section Eight—Ductwork, Dampers and Terminal Devices

8.3.5 Supports for floor-mounted ductwork shallbe provided and flange-bolted to support pads orplinths.

8.4 INSPECTION AND TESTS

8.4.1 The Contractor shall issue a certificateconfirming that all ductwork constructions complywith the relevant HVCA Specification DW/142 andAddendum A tabulated gauges. Notwithstanding this,the PM reserves the right to have random discs of50mm diameter, (or equivalent), cut at site in anyductwork range for the purpose of checking the gaugeof the material used. Such check cuts shall be madegood by covering with 80mm diameter, (or equivalent),plate of 'ductwork' gauge secured with self-tappingscrews and sealed with mastic.

8.4.2 Ductwork systems or sections thereof, shallbe leak tested in accordance with Section Twenty-Six—Inspection, Testing and Commissioning—of thisSpecification.

8.5 PLASTICS DUCTWORK

8.5.1 Ductwork materials and constructions shallcomply with HVCA Specification DW/151.

8.5.2 Plastics ductwork and all associatedmoulded or extruded sections, angles and fittings shallbe suitable for the range of substances conveyed andthe conditions as indicated.

8.5.3 Unless otherwise indicated, sheet materialshall be pressed unplasticised PVC sheet complyingwith BS 3757. Where PVC ductwork is thermallyinsulated or is not readily visible, Type A2 sheet shallbe used. Elsewhere, Type Al sheet shall be used.

8.5.4 Any plastics ductwork systems incorporatinga heater battery shall be installed such that no part ofthe system is impaired by the heating effects of thebattery or its casing.

8.5.5 Where indicated, ductwork shall bereinforced with glass fibre/resin laminate.

8.6 ALUMINIUM DUCTWORK

8.6.1 Where aluminium ductwork is specified, itshall comply with HVCA Specification DW/142 andAddendum A. The grade of aluminium shall be asindicated.

8.7 PVC COATED SHEET STEEL DUCTWORK

8.7.1 Where PVC coated sheet steel ductwork isspecified, the sheet thickness and constructionspecification shall be as for galvanised sheet steelductwork of the same size. The sheet steel shall begalvanised and coated with PVC film at least 0.25mmthick on one or both sides as indicated. Care shall betaken to preserve the coating during ductworkmanufacture and erection.

8.8 STEEL DUCTWORK, GALVANISED AFTERMANUFACTURE

8.8.1 Where galvanised after manufacture steelductwork is specified it shall comply with HVCASpecification DW/142 and Addendum A.

8.9 STAINLESS STEEL DUCTWORK

8.9.1 Where stainless steel ductwork is specified itshall comply with HVCA Specification DW/142 andAddendum A. The grade of stainless steel shall be asindicated.

8.10 BENDABLE DUCTS AND FLEXIBLE DUCTS

8.10.1 Bendable ducts and flexible ducts shall bemetal, plastic coated metal or non-metallic type asindicated.

8.10.2 Where bendable ducts and flexible ducts arespecified, the internal diameter of the duct shall beequal to the external diameter of the rigid duct orequipment spigot. Flexible ducts in other situationsshall only be used with the approval of the PM. Themaximum length of any individual duct shall notexceed 3m.

8.10.3 Non-metallic ducts shall have a liner and acover of tough tear-resistant fabric. The fabric shall beimpregnated and coated with plastics and reinforcedwith a bonded galvanised steel spring, stainless steelor other approved wire helix between the liner and thecover. An outer helix of glass fibre cord, or equal, shallbe bonded to ensure regular convolutions. Flexibleductwork without a liner may be used subject tocompliance with all the other appropriaterequirements of this section.

8.10.4 Metallic ducts shall consist of corrugatedmetal tubing of stainless steel, aluminium, galvanisedsteel or aluminium coated steel. The metal surface(s)may be coated with a plastics material.

October 1997 39



8.10.5 The frictional resistance to air flow per unitlength of bendable duct or flexible duct shall notexceed 150% of the frictional resistance per unitlength of galvanised steel duct of similar diameter.The radius ratio R/D for bends shall be not less than2, where R is the centre line radius and D is thediameter of the duct.

8.10.6 The leakage from any section of bendableduct or flexible duct shall meet the requirements forairtightness applicable to rigid ductwork for thepressure classification specified.

8.10.7 Unless otherwise indicated, bendable ductsand flexible ducts shall be suitable for an operatingtemperature range of -5°C to +90°C and shall complywith BS 476 as follows: Part 12—having Class Prating; Part 6—having an index of performance (I) notexceeding 12, of which not more than 6 should bederived from the initial period of test; Part 7—beClass 1 rated (surface of very low flame spread).

8.10.8 Test holes shall not be formed in bendablenor flexible ductwork.

8.11 LIGHTWEIGHT DUCTING

8.11.1 Resin-bonded mineral fibre ductwork

8.11.1.1 Resin-bonded mineral fibre ductwork shallbe fabricated in accordance with 'HVCA DW/191—Code of Practice for resin-bonded glass fibreductwork'.

8.11.1.2 Board for ducts shall be faced with glassreinforced aluminium foil.

8.11.1.3 Joints shall be reinforced with an internalsheet metal sleeve.

8.11.1.4 Fabrication shall be undertaken by aspecialist company.

8.11.2 Aluminium/phenolic foam board ductwork

8.11.2.1 Ductwork shall be fabricated from phenolicfoam board faced on sides and edges with 28 micronglass reinforced aluminium sheet.Ductwork shallcomprise 28 micron (minimum) aluminium sheets,reinforced with 5 mm glass fibre scrim, enclosingclosed cell phenolic foam board.

8.11.2.2 Joints shall be either male/female glued andsealed connections or aluminium jointing profilesfitted and sealed to duct ends. Ductwork sections shallbe assembled with self adhesive sealing gasket andjoints rivetted on all sides.

8.11.2.3 Ductwork and joints shall comply withrequirements of HVCA DW/142.

8.11.2.4 General details of construction methods andsupport shall be to HVCA DW/191.

8.11.2.5 Additional support positions shall beprovided as indicated.

8.11.2.6 Fabrication and erection shall beundertaken by a Specialist company.

8.11.2.7 The ductwork installation shall comply withParts 6 and 7 of BS 476.

8.12 DAMPERS

8.12.1 General

8.12.1.1 The general constructional requirements ofdampers shall be in accordance with HVCASpecification DW/142. The respective functions andtypes shall be as indicated. Damper frames and bladesshall be constructed to ensure rigidity and preventdistortion and jamming in operation. The blades shallbe securely fixed to the operating spindles so thatdifferential movement cannot occur. Spindles shall becarried in non-ferrous or nylon plain bearings or inball bearings.

8.12.1.2 An access opening shall be provided for eachdamper and shall be located to provide access forinspection and maintenance.

8.12.1.3 Manually and automatically operateddampers shall include a means for indicatingexternally the position of the blades. Manual dampersshall include a device for positioning and locking thedamper blades. Ratchet and pawl locking devices arenot acceptable.

8.12.1.4 The position of all dampers, as set after finalregulation, shall be permanently marked at theadjusting device.

8.12.1.5 Balancing dampers shall be fitted in eachbranch from a main or sub-main and whereverindicated.

8.12.1.6 Unless otherwise indicated, air leakagethrough dampers when in the closed position shall notexceed 5% of the maximum design air volume flowrate at the maximum design air total pressure. Whereindicated, air leakage tests to verify compliance withthis Clause, shall be carried out in accordance with BS6821.

40 October 1997



8.12.2 Non-return dampers

8.12.2.1 Non-return dampers shall be of themotorised type and shall be arranged to close ondetection of failure of air flow except those for smallpackaged duplicate-fan extract units.

8.12.3 Fire dampers

8.12.3.1 Unless otherwise indicated, fire dampersused singly or in combination shall have an overallfire rating not less than 2 hours. In all cases, evidenceof fire rating in accordance with BS 476: Part 22 shallbe provided by a NAMAS accredited test laboratory.

8.12.3.2 Unless otherwise indicated, each firedamper shall be held in the open position by acorrosion-resistant retaining device incorporating areplaceable fusible element. Unless otherwiseindicated, the fusible element shall operate at atemperature of 72°C.

8.12.3.3 No duct lining or bendable duct or flexibleduct shall be installed within 1m of a fire damper.

8.12.3.4 Fire dampers shall be constructed fromeither a corrosion-resistant material such as stainlesssteel, or be galvanised or otherwise treated tominimise corrosion. The dampers shall be housed in arigid framed, corrosion-resistant casing which shallnot distort under fire conditions. Provisions shall bemade to accommodate expansion of the damperblade(s) within the casing in fire conditions. A firedamper installation frame shall also incorporateprovision for expansion within the surroundingstructure, together with lugs for building into thestructure.

8.12.3.5 Fire damper assemblies for installation incorrosive environments, or where corrosive agentsoccur in the ducted air, shall be fabricated frommaterial or be coated with a protective finish resistantto the corrosive substances and conditions indicated.

8.12.3.6 Each fire damper casing shall be clearlymarked with a permanent indication of the correctfixing attitude of the damper, the direction of air flowand the side at which access or maintenance openingsshall be located.

8.12.3.7 The Contractor shall demonstrate thatsatisfactory access for operating and resetting of alldampers in their installed locations has been provided.

8.12.3.8 The folded continuous interlocked blade typeof damper may be used for vertical or horizontal ductapplications. The closing force for these types of

dampers shall be provided by a stainless steel springor springs. An automatic locking device shall beprovided to ensure that the blades are firmly held inthe closed position after release. In the open (normal)position, all blades shall be completely out of theairstream. This type of damper only shall be used inhigh velocity systems.

8.12.3.9 Spring-actuated pivoted single blade ormulti-bladed dampers may be used for vertical orhorizontal duct applications. Multi-bladed dampersshall be provided with a means to ensure that allblades close simultaneously.

8.12.3.10 Gravity-operated multi-bladed fire dampersshall only be used in horizontal ducts.

8.12.3.11 Gravity-operated single blade dampers maybe used for both vertical and horizontal ducts,provided that means are incorporated which ensurereliable and positive closure when operating inmaximum air flow rate conditions.

8.12.3.12 Where gravity-acting, off-centre pivoteddampers incorporate spindle bearings, long-termcorrosion effects shall be minimised by choice ofmaterials. Bearings shall be sealed and capped toexclude dirt and dust. Damper blades shall close tocomply with the stability and integrity requirementsof BS 476: Part 22.

8.12.3.13 Where indicated, provision shall be made toremotely indicate that a fire damper is in the closedposition.

8.12.3.14 Intumescent type fire dampers shall only beused where indicated.

8.13 ACCESS OPENINGS, CLEANING AND INSPECTIONCOVERS

8.13.1 All access openings shall have rigid frameswith air sealed covers, designed for ease of removaland re-fixing, secured with a minimum number ofproprietary quick-release captive fastenings consistentwith effective air sealing. Set screws, set bolts or self-tapping screws will not be acceptable as fixing devices.

8.13.2 Access openings shall be provided as statedin HVCA Specification DW/142. Access openings forcleaning purposes shall be as indicated.

8.13.3 Hinged access doors shall be provided whereindicated.

8.13.4 Inspection covers shall be provided whereindicated.

October 1997 41



8.14 HOODS

8.14.1 Hoods shall be of the material(s) indicated,rigidly formed and be supported independently ofductwork. Unless otherwise indicated, support shall beprovided either from above or from a side wall.Horizontal joints in sheets are not acceptable. Thetype and size of hood shall be as indicated, but theexact position shall be approved by the PM.

8.14.2 Hoods for kitchen equipment, and for theextraction of vapours, shall have an internal perimetergutter with a plugged drain connection. Hoods shall benon-combustible and comply with BS 476: Part 22 andBS 476: Part 3, Class AA (without suffix X). Greasefilters, in accordance with Section Four—Air Filters—of this Specification, shall be incorporated.

Fire dampers shall be provided as indicated.

8.14.3 Hoods provided over deep pan fryers shallbe vented direct to the open air by the shortestpossible route and shall not incorporate a fire damper.

8.14.4 Gutter drains shall be extended to near floorlevel after installation of the hood.

8.14.5 Suitable electric lighting shall be provided inhoods as indicated.

8.14.6 Cleaning doors shall be provided in ductsconnected to hoods and canopies as indicated.

8.15 TEST HOLES

8.15.1 Test holes for plant system commissioningshall be fitted with 13mm diameter easily removablerubber or neoprene sealing plugs. Test holes shall beprovided in locations stated in HVCA SpecificationDW/142, and additionally in all branch ducts inlocations not unduly influenced by local fittings.Further requirements for test holes shall be asindicated.

8.16 IDENTIFICATION

8.16.1 Ductwork identification shall be inaccordance with Section Seventeen—ThermalInsulation—of this Specification.

8.17 AIR TERMINAL DEVICES

8.17.1 General

8.17.1.1 The testing and rating of air terminaldevices shall be in accordance with BS 4773: Part 1and Part 2.

8.17.1.2 Sizes of all terminal devices shall be basedon the dimensions and/or duty indicated and shallprovide the air volume flow rate, air diffusion and anyother requirements as specified. The indicated soundpower levels shall not be exceeded.

8.17.1.3 The materials of construction shall be steel,aluminium or plastics as indicated. All items shall beprotected against corrosion and be provided in thefully furnished condition indicated. Visible internalfixings shall be a matt black finish.

8.17.1.4 The full perimeter of all air terminal deviceslocated on walls or ceilings, shall be provided with aresilient sealing strip. Where indicated, special devicesshall be incorporated to prevent pattern staining.

8.17.1.5 Each air terminal device shall be firmlyfixed in position, be level and aligned with adjacentterminals.

8.17.1.6 Press-in spring clip fixings are notacceptable other than for sill or floor mounted airterminals. Grille or diffuser cones shall be removablewhere indicated.

8.17.1.7 Damper adjustment mechanisms shall beconcealed from casual view, finished matt black and beoperable by hexagonal wrench or screw-driver. For upto ten units of any particular type of air grille, registeror diffuser, one set of any special tools required foradjusting shall be provided; from eleven to twenty-four, two sets; twenty-five and over, three sets.

8.17.2 Grilles and registers

8.17.2.1 Grilles and registers for supply air shallhave two sets of adjustable blades, one set horizontaland one set vertical. Unless otherwise indicated, theair flow rate controller for supply air registers shall bea damper of the opposed blade multi-leaf type orrhomboidal type.

8.17.2.2 Grilles and registers for extract air shallhave a single set of adjustable blades either horizontalor vertical, or a lattice or egg crate front as indicated.The air flow rate controller for extract air registersshall be a damper of the opposed blade multi-leaf type.

8.17.2.3 The blades of all grilles and registers shallbe adjustable from the front and shall have a frictiondevice to retain set positions. The air flow ratecontroller of all registers shall be adjustable from thefront.

42 October 1997



8.17.3 Diffusers

8.17.3.1 Unless otherwise indicated, each diffusershall be provided with an air flow rate controller anda means of altering the discharge air flow pattern. Allcontrollers shall be adjustable from the front of thediffuser. Where a diffuser is directly connected to astub duct which has a straight length of less than twoequivalent diameters, an equalising deflector shall beused.

8.17.3.2 Cone type diffusers shall be provided, whereindicated, with finish as indicated.

8.17.3.3 Linear diffusers shall be of the fixed bladetype, or shall include means of independentlyadjusting the direction of the air jets, as indicated.The method of air volume flow rate control shall be asindicated. Where linear diffusers are mounted in acontinuous line, there shall be provision for ensuringalignment between consecutive diffusers and eachdiffuser shall be provided with means to ensureuniform air flow distribution along the diffuser.Plenum boxes and duct connections shall be inaccordance with manufacturers' recommendations.

8.17.3.4 Circular diffusers, with adjustable air flowpattern, shall have the cone retained by a screwedspindle fitted with upper and lower stop pins or otherapproved method.

8.17.4 Swirl type diffusers

8.17.4.1 Swirl type diffusers shall be floor or ceilingmounted type.

8.17.4.2 Floor diffusers shall have removable dustboxes.

8.17.4.3 Units shall be of rigid box construction withfront plate containing air guides to produce theperformance required.

8.17.5 Displacement ventilators

8.17.5.1 Displacement ventilators shall be ofgalvanised mild sheet steel construction withperforated face panels, base plate and circularconnection collar for ducts.

8.17.5.2 Ventilators shall contain low resistancebaffle, equalising grid or other device to ensure evendistribution over perforated face panels.

8.17.5.3 Perforated face panels to be easy removabletype for cleaning and maintenance or replacement ofair distribution component.

8.17.5.4 Outlet surfaces shall be as shapes indicated.Ventilators shall be suitable for floor mounting.

8.17.5.5 Noise levels shall not exceed NR ratingsindicated.

8.17.6 External louvres

8.17.6.1 All air intake and exhaust points shall beprotected with louvres designed to prevent ingress ofrain.

8.17.6.2 Ductwork immediately behind a verticalintake or exhaust louvre shall be painted on allinternal surfaces with epoxy resin or bitumastic paintfor a length from the louvre equal to the louvreheight, or to the nearest equipment item, whichever isthe lesser. The bottom side of the ductwork shall havea 15 degree minimum slope towards the louvre.

8.17.6.3 Frames and blades shall be fabricated fromgalvanised mild steel sections and sheet, or fromaluminium alloy of adequate stiffness to preventvibration and/or damage. All louvres shall be fullyprotected against corrosion and be provided in thefully finished condition indicated.

8.17.6.4 Galvanised mild steel louvres shall beassembled with non-corrodible bolts.

8.17.6.5 Vermin screens shall be fitted to all externallouvres and shall be removable for cleaning.

8.17.6.6 The method of fixing louvres shall be bybolting through the casing flange or side casing tostructural members. An effective weather and acousticseal shall be achieved using packing and fillingmaterials as necessary.

8.17.6.7 Acoustic louvres shall be provided whereindicated, and shall consist of a rigid casing housingdouble-skin blades having plain top surfaces andshaped, perforated undersides to achieve maximumattenuation, utilising infill material packed in sealedplastic film containers. Infill material shall complywith Section Twenty-One—Vibration Isolation andNoise Insulation—of this Specification. Acousticperformance shall be as indicated. Test results sheetsshall be available.

8.17.7 Roof cowls

8.17.7.1 Cowls shall be manufactured from pressedsheet steel (galvanised after manufacture, and/orpainted in accordance with the finishing schedules),spun aluminium or aluminium sheet, as indicated.Alternatively, or where indicated, construction shall be

October 1997 43



from self-coloured moulded glass reinforced plastics toBS 3532 assembled with fittings as compatible, and ofnon-corroding materials, to suit the application.

8.17.7.2 The exterior shape and the mounting andfixing arrangements of the cowls shall withstand themaximum windspeed indicated and shall be suitablefor the roof structure.

8.17.7.3 Backdraught dampers shall be fitted todischarge cowls and shall be suitable for the type andconditions of the gases handled. Automaticallycontrolled opening shall be provided where indicated.The dampers, when closed, shall limit leakage to 5% ofthe design air flow.

8.17.7.4 Vermin screens shall be fitted to all roofcowls and shall be removable for cleaning.

44 October 1997


Section Nine—Air Control Devices IncludingInduction, Terminal Reheat and Vav Units

9.1 GENERAL

9.1.1. Testing and rating of terminal units shallmeet the requirements of BS 4979 or BS 4954 or BS4857 as appropriate.

9.1.2 Casings for all types of unit shall becorrosion resistant and of rigid construction.Alternatively, if of sheet steel, treatment to preventcorrosion shall be applied internally and externally.All corners shall be free of sharp edges.

9.1.3 Full provisions for suspension or fixing shallbe incorporated together with manufacturers'comprehensive installation instructions.

9.1.4 Account shall be taken of requirements toenclose units within builder's work casings or forspecial finishes as indicated.

9.1.5 Thermal insulation and acoustic liningsshall be non-combustible and shall comply withSection Seventeen—Thermal Insulation—and SectionTwenty-One—Vibration Isolation and NoiseInsulation—of this Specification as applicable. Liningmaterials shall not support bacterial growth.

9.1.6 Mineral fibre insulation shall not be usedwithin terminal unit sections unless factory appliedand contained within an impervious membrane.

9.1.7 The noise level in the space, with each unitoperating at its design air volume flow rate, shall notexceed the noise rating (NR) indicated. Acoustic datashall be provided including octave band analysis of thesound power level of the unit under free-fieldconditions.

9.1.8 Sample units shall be batch-tested at themanufacturer's works to check for compliance with allrequirements of this Specification.

9.2 INDUCTION UNITS

9.2.1 All components shall comply with theappropriate sections of this Specification except that:

a) The coils shall be protected by air screenswhich may be of nylon fibre or glass fibre andshall be suitable for collecting lint from therecirculated air.

b) Unless otherwise indicated, cooling coils andheating coils shall be formed of copper tubeswith aluminium fins.

9.2.2 Unless otherwise indicated, casings shall beprovided as part of the unit. Casings shall includespace for pipework connections, valves and air ductingas necessary, with ready access to the air screen, theprimary air nozzles, pipework connections, valves andcontrols.

9.2.3 Units shall be complete with a device toregulate primary air pressure and air volume flowrate. Primary air nozzles shall be arranged to inducean even secondary circulation across the cooling and/or heating coils. The unit air outlet shall incorporatemeans of directional control of air supply.

9.2.4 Cooling and heating coils shall have an airrelease cock and be arranged to prevent air leakagearound the coil. Cooling coil drain trays shall beprovided and be extended to beneath the control valveassembly. Construction, corrosion protection, drainageand trapping arrangements shall be completely inaccordance with Section Five—Air Heater and CoolerBatteries—of the Specification. Drainage pipes shalldischarge at the positions indicated.

9.3 SINGLE AND DUAL DUCT TERMINAL UNITS

9.3.1. Units shall incorporate a self-acting constantflow rate device. The pressure drop across the unit atthe design air volume flow rate shall not exceed 250 Pa.

October 1997 45


Section Nine—Air Control Devices Including Induction, Terminal Reheat and Vav Units

9.3.2 Dual duct terminal units shall incorporatedevices for varying the proportions, and for providingthorough mixing, of hot and cold air. With the inletcontrol device or devices at the closed position, the airleakage across the device at the specified pressureshall not exceed 2% of the maximum air volume flowrate for which the unit is designed. Suitable provisionsshall be made for access to all components.

9.4 VARIABLE AIR VOLUME (VAV) UNITS

9.4.1 VAV control units shall be installed inassociation with a variable air volume system, havingcontrol of the fan output relative to system demands.Pressure stabilisers and air flow rate controllers shallbe incorporated. Units shall be factory-set orresettable as indicated.

9.4.2 Units shall be capable of adjustment to aminimum air position or complete shut-off as indicatedand shall respond to the dictates of a temperaturesensor mounted in the occupied space. Variablegeometry or other means may be utilised to ensureconsistent air distribution throughout the required airvolume range as indicated.

9.4.3 Units shall have an inlet spigot and an outletspigot for flexible duct connections to serve single ormultiple air terminal devices as indicated. Outletsshall have integral butterfly type balancing dampers.

9.4.4 Fan assisted VAV terminal units shall beVAV units as previously described complete with aprimary/room air mixing section, primary air volumecontroller and forward curved centrifugal supply fan.Fan and mixing sections shall be provided with accesspanels. Fans shall be easily removable from the unitand may be of mild steel, aluminium, reinforced glassfibre or rigid plastic material.

9.4.5 Where indicated, reheat units shall beinstalled in conjunction with a control unit and outletbox as required. Reheat units shall be of the hot wateror electric type as indicated.

9.4.6 Air terminal devices shall be suitable formounting in ceiling suspension systems or for beingindependently supported as indicated.

9.5 UNDERFLOOR FAN-ASSISTED AIR UNITS

9.5.1 Fan-assisted air units shall be mountedwithin floor voids and shall comprise a stiffenedgalvanised sheet metal box internally lined with non-combustible acoustic material complying with SectionTwenty-One—Vibration Isolation and NoiseInsulation—of this Specification.

9.5.2 Each vertical side of the box shall have aspigot for a flexible duct connection to a floor mountedsupply air terminal or to a work station unit.

9.5.3 The top surface of the box shall accept aradial type fan mounted on a plate which shall befixed in position by quarter-turn spring-loaded quick-release fasteners. The air inlet shall be provided onthe underside of the box.

9.5.4 The fan motor shall have a flexible cord of3m length for connection as indicated. The unit shallbe suitable for manual and automatic operation from aremote location with provision for local override.

9.5.5 Duties of underfloor fan-assisted units shallbe as indicated.

9.6 CONSTANT VOLUME FLOW REGULATORS

9.6.1 Flow regulators shall comprise a sheet metalbox or cylindrical section, housing a damped-action aircontrol device. Units shall be factory-set or resettableas indicated.

9.6.2 Regulators shall be provided with inletpressure adjustment to achieve the required airvolume flow rate in accordance with calibration data.

46 October 1997


Section Ten—Fan Coil Units

10.1 GENERAL

10.1.1 Fan coil units shall comprise a framehousing a fanset with anti-vibration mountings andcooling and/or heating coil with control valve anddrain tray.

The following items shall also be included:

fresh air spigot where indicated,

air filter,

recirculation air spigot and grille,

a)

b)

d)

e)

f)

g)

h)

supply air grille with two sets of adjustableblades,

thermal insulation and acoustic lining,

casing, with access panels as indicated,

additional ducting where indicated,

mounting or suspension provisions.

10.1.2 All components shall comply with theappropriate sections of this Specification except that:

a) Fans, which shall be easily removable fromthe unit, may be of the forward curvedcentrifugal or tangential flow types and maybe of mild steel, aluminium, reinforced glassfibre or rigid plastics material.

b) Air filters may be of nylon fibre, glass fibre orcellular plastics materials and shall be Grade3 when tested in accordance with BS EN 779.

c) Unless otherwise indicated, cooling coils andheating coils shall be formed of copper tubeswith aluminium fins. Aluminium fins forcooling application shall be complete withanti-corrosion protection.

10.1.3 Variable refrigerant volume (VRV) unitsshall be complete with refrigeration flow selectordevice for heating or cooling application. All

assemblies and refrigeration distribution pipeworkshall comply with BS 4434 and Section Two—Refrigeration Plant, of this Specification.

10.1.4 The volumetric and thermal performance offan coil units shall meet the requirements indicatedand comply with Section Seventeen—ThermalInsulation, and Section Twenty-One—VibrationIsolation and Noise Insulation, of this Specification.Testing and rating shall be in accordance withBS 4856: Parts 1 to 5 inclusive, as applicable to suitthe particular arrangements.

10.1.5 The noise level in the space, with each unitoperating at its normal speed, shall not exceed thenoise rating (NR) indicated. Acoustic data shall beprovided including octave band analysis of the soundpower level of the unit produced at each available unitspeed under free-field conditions.

10.2 CASINGS

10.2.1 Unless otherwise indicated, casings shall beprovided as part of the unit. Casings shall includespace for pipework connections and valves with readyaccess to the fan and motor, filter, damper, drain tray,pipework connections, valves and controls.

10.2.2 Casing shall be corrosion resistant and ofrigid construction. Alternatively, if of sheet steel,treatment to prevent corrosion shall be appliedinternally and externally. All corners shall be free ofsharp edges.

10.2.3 Account shall be taken of requirements toenclose units within builder's work casings or forspecial finishes as indicated.

10.3 COMPONENTS

10.3.1 Cooling coils shall be two rows minimumdepth and shall include an air vent.

October 1997 47


Section Ten—Fan Coil Units

10.3.2 Cooling coil drain trays shall be providedand be extended to beneath the control valveassembly. Construction, corrosion protection, drainingand trapping arrangements shall be completely inaccordance with Section Five—Air Heater and CoolerBatteries—of this Specification. Drainage pipes shalldischarge at the positions indicated.

10.3.3 Unit fans shall be rated for the resistance ofexternal ductwork where indicated.

10.4 ARRANGEMENT OF UNITS

10.4.1 The arrangement of units, (eg wall, floor orceiling mounted), the position of discharge andrecirculation grilles, (if any), and the need for sheetmetal casing shall be as indicated.

10.5 CONTROLS, DAMPERS AND GRILLES

10.5.1 Fan coil units shall have motors andcontrollers to provide at least two running speeds andan 'OFF' position. Where indicated, there shall beconnections for both fresh air and recirculated air withadjustable dampers to provide up to 25% of designvolume as fresh air. Supply grilles shall provideadjustment of air flow direction without increasingpressure loss. Where floor mounted units are specified,supply grilles shall be on the top of the unit unlessotherwise indicated. Where the return air inlet is onthe front face of the unit, the supply grille shall havea vertical discharge.

10.5.2 Automatic control of the unit shall bearranged with a 'dead zone' to prevent simultaneousheating and cooling within any single space served.

48 October 1997


Section Eleven—Ventilating, Kitchen Ventilatingand Chilled Ceilings, Chilled Beams and PlatformFloors

1 1 . 1 GENERAL

11.1.1 Ventilating ceilings and platform floors shallhave a current BBA Agrement Certificate statingsuitability for use.

11.1.2 Ceiling and floor voids shall becompartmented as indicated to effect control overspread of fire. Fire dampers, with access for resetting,shall be provided where indicated.

11.1.3 The alignment of the ceiling installation inthe horizontal and vertical planes shall be to thetolerances indicated and shall be to the satisfaction ofthe PM.

1 1 . 2 VENTILATING CEILINGS

11.2.1 The air volume flow rate, sound absorptioncoefficient, sound reduction index, fire performance,light reflectance, module dimensions and permissibleloading of ventilating ceilings shall be as indicated.

11.2.2 The types(s) of ceiling shall be one of thefollowing as indicated:

a) Tiles with regular perforations.

b) Tiles with random perforations or fissures.

c) Purpose-made pressed metal sectionsincorporating adjustable elongated slots andfitted to the edges of standard acoustic tiles.

d) Continuous rows of air injection slotsinterposed in a linear arrangement of metalstrips backed with a sound absorbingmaterial.

All ceilings shall be provided with purpose-madehinged service access panels as indicated.

11.2.3 Ceiling tiles shall be of gypsum plaster,metal or other materials as indicated.

11.2.4 Final surface finishes shall be applied totiles by the manufacturer prior to delivery to site. Thefinish to non-metallic tiles shall be applied to allexposed surfaces, edges, and internal surfaces ofperforations and fissures to prevent erosion andshedding of dust.

11.2.5 Fibrous materials used for acoustic purposesin conjunction with ventilating ceilings shall becompletely sealed within an impervious envelope andshall not shed dust or fibre particles. Fire performanceof the impervious envelope shall meet therequirements indicated.

11.2.6 Unless otherwise indicated, the Contractorshall minimise air leakage from the plenum void andbetween compartmented zones in the void by caulkingof all penetrations for services and structuralelements. The Contractor shall also ensure that thevoid is dust-free and the vapour seal is complete.

11.2.7 The ceiling design shall permit theinterchange of ventilating and non-ventilatingsections.

11.2.8 The arrangement of the ceiling suspensionsystem shall sustain the maximum force exerted dueto the system air static pressure and the weight of theceiling, including luminaires, access panels and otherequipment loadings included in the assemblies.

11.2.9 The airstream velocity from supply airdischarge point(s) into the ventilating ceiling shall notexceed 4m/s.

11.2.10 Supply duct spigots shall be provided withopposed blade regulating dampers. Branch supplyducts shall be fitted with deflectors that direct the

October 1997 49


Section Eleven—Ventilating, Kitchen Ventilating and Chilled Ceilings, Chilled Beams and Platform Floors

supply air flow as necessary, in order to preventinduced air flow into the void, or any otherdisturbance within the plenum and to avoid anyobstruction.

1 1 . 3 VENTILATING PLATFORM FLOORS

11.3.1 The air volume flow rate, sound absorptioncoefficient, sound reduction index, fire performance,floor finish, module dimensions and permissibleloading of ventilating platform floors shall be asindicated.

11.3.2 Builder's work surfaces in floor voids shallbe rendered dust-free by the use of an approvedsealant/vapour barrier applied by the Contractor.

11.3.3 Floor tiles shall have soft sealing edges toprevent air leakage.

11.3.4 Grilles or other terminal devices shall besufficiently robust to withstand loadings associatedwith normal use of the occupied space, and shall beinterchangeable with floor tiles.

11.3.5 The airstream velocity from supply airdischarge point(s) into the floor void shall not exceed4m/s.

11.3.6 The Contractor shall ensure that all dustcollecting ledges and associated spaces within platformfloor voids are clean before handover.

11.3.7 Perforated floor tiles including finishes shallbe as indicated.

1 1 . 4 KITCHEN VENTILATING CEILINGS

11.4.1 Special demountable modular panel kitchenventilating ceilings shall be of proprietary supply andconstructed from non-combustible, non-corrosive,easily cleanable material. Provision shall be made forthe collection of condensate.

11.4.2 The ceiling shall comprise a framework andreadily removable extract, supply, and blank panelscleanable in a commercial dish washer.

11.4.3 Extract panels shall be located over cateringequipment and separate ducted air inlet panels andblank panels shall be provided as indicated on thedrawings.

11.4.4 Ceiling void vertical dividers shall be fittedbetween extract and supply air sections and shall beof rigid stainless steel sheet.

1 1 . 5 CHILLED CEILINGS

11.5.1 Chilled ceilings shall comprise coppercooling coils fixed directly to the underside ofperforated metal carrier plates.

11.5.2 Insulation in an impervious envelope shallbe positioned above the perforated plate and the coil,plate and insulation shall be located into proprietaryceiling tiles.

11.5.3 Pipework connections to coils shall be quickrelease flexible type. Provision shall be made to ventand drain coils and associated distribution pipework.

11.5.4 Service access panels, luminaires, supplyand extract terminals and other items shall beincorporated in the ceiling layouts as indicated on thedrawings.

11.5.5 The ceiling shall be adequately supportedfrom the building structure. Individual coil sectionsshall be demountable and complete with facility toisolate, disconnect, and replace each coil, luminaire,ventilation terminal or other ceiling item.

11.5.6 The design and method of installing theceiling panels and associated framework shall ensurecontinuous neat lines where ceiling components joinluminaires and ventilation terminals.

11.5.7 Coils, distribution pipework and valves shallcomply with Section—Fourteen—Pipework, Section—Fifteen—Valves Cocks and Strainers, and SectionTwenty Six—Inspection, Testing and Commissioning,of this Specification.

1 1 . 6 CHILLED BEAMS

11.6.1 Chilled beams shall be suspended below orbe recessed into ceilings. For fully recessed units, airinlet/outlet diffusers shall be flush with ceilings anddiffusers and housings shall be provided with meansto adjust diffuser edges to obtain a neat line withceilings.

11.6.2 Heat exchangers shall comprise copper tubeswith aluminium, vinyl coated aluminium, epoxy coatedaluminium or copper fins as indicated. Fins withminor damage shall be combed straight. Units withextensive damage to fins will not be accepted.

11.6.3 Unless otherwise indicated heat exchangerhousings for recessed units shall be of rigid airtightconstruction to ensure room air does not by-pass heatexchangers.

11.4.5Officer.

Installations shall be approved by the Fire

50 October 1997

Specification 037 Section Eleven—Ventilating, Kitchen Ventilating and Chilled Ceilings, Chilled Beams and Platform FloorsAir conditioning, air cooling andmechanical ventilation for buildings

11.6.4 Where ceiling void spaces/roof void spacesare used to recirculate room air through heatexchangers, fibrous material shall not be used toinsulate the ceiling, pipework, ductwork and othercomponents in these spaces. Ceiling tile acousticinsulation shall comply with clause 11.2.5.

October 1997 51

11.6.5 Provision shall be made to isolate,disconnect and replace individual heat exchangersections and vent and drain all coils and associateddistribution pipework.

11.6.6 Heat exchangers, distribution pipework, andvalves shall comply with Section Five—Air Heater andCooler Batteries, Section Fourteen—Pipework, andSection Fifteen—Valves Cocks and Strainers, of thisSpecification.


Section Twelve—In-room Air Conditioning Units

12.1 GENERAL

12.1.1 In-room air handling units shall be completewith all components necessary to achieve the dutiesand environmental conditions indicated. Compressorsto be installed either within in-room units or externalcondensing sets shall be as indicated. Water-cooledcondensers shall be provided where indicated.

12.1.2 The noise level in the space, with the unitoperating at normal speed, shall not exceed the noiserating (NR) indicated. Acoustic data shall be providedincluding octave band analysis of the sound powerlevel of the unit produced at each available unit speedunder free-field conditions.

12.1.3 For comfort condition application, internalcomponents shall comply with Section Ten—Fan CoilUnits—of this Specification.

12.2 CONSTRUCTION

12.2.1 Cabinets shall be of framed rigidconstruction to prevent distortion and drummingwhen in operation and shall be provided with easilyremovable front and side access panels formaintenance and operational adjustment of allcomponent items. Panels shall be 1.2mm minimumthickness mild steel sheet held by quarter-turn spring-loaded quick-release fasteners.

12.2.2 The automatic control section shall beseparated from the electrical power enclosure.

12.2.3 All service connections shall be containedwithin the unit cabinet.

12.2.4 All constructions shall be degreased afterassembly, treated to provide corrosion resistance andepoxy-resin painted, baked on after application, orother approved finish. Colours shall be as indicated.

12.2.5 Fresh air inlet connections shall be providedwhere indicated with filtration to the Class indicated.

12.3 UNITARY REVERSE CYCLE HEAT PUMPS

12.3.1 Reverse cycle units shall include thefollowing main components:- compressor, centrifugalfan, refrigerant flow reversing valve, capillaryexpansion valve, refrigerant/room air heat exchanger,refrigerant/water heat exchanger and air filter. Waterheat exchangers to be connected to common watercircuit supplying or absorbing heat from units onheating or cooling cycle. The refrigeration installationshall comply with BS 4434.

12.3.2 All items shall be mounted on a commonframework with access for inspection service andmaintenance.

12.3.3 Units shall be of robust construction andsufficiently rigid to operate under all serviceconditions without drumming or vibration. Leakage isnot acceptable under any operating conditions.

12.3.4 Each unit shall be complete with initialcharge of refrigerant and lubricating oil and preparedends flexible pipe connections.

12.3.5 The unit operating mode shall beautomatically controlled by a thermostat, with manualadjustment, either in the unit or remotely mounted.

12.3.6 Tests shall be made in accordance withaccepted Standards and Codes of Practice.

12.3.7 The noise level in rooms, with each unitoperating at its normal speed shall not exceed thenoise rating (NR) indicated. Acoustic data shall beprovided including octave band analysis of the soundpower level under free field conditions.

12.3.8 Anti-vibration mountings shall be inaccordance with Section Twenty-One—VibrationIsolation and Noise Insulation—of this Specification.

52 October 1997


Section Twelve—In-room Air Conditioning Units

12.4 INSULATION

12.4.1 Cabinets shall be thermally insulated andacoustically lined in accordance with SectionSeventeen—Thermal Insulation, and Section Twenty-One—Vibration Isolation and Noise Insulation, of thisSpecification.

12.5 GRILLES

12.5.1 Units shall be arranged for upflow ordownflow applications as indicated and shallincorporate return air and/or discharge air grilles asindicated. Grilles shall incorporate vertical andhorizontal adjustable blades and be easily removable.

12.6 AIR FILTERS

12.6.1 Units shall have air filters, of the Classindicated, in accordance with the requirements ofSection Four—Air Filters of this Specification. Adifferential pressure switch used in conjunction with awarning lamp shall indicate when filter maintenanceis required.

12.7 FANS

12.7.1 Fans shall be of the forward curvedcentrifugal type in accordance with Section Three—Fans of this Specification. Fan shafts shall be of mildsteel running in sealed bearings for sizes up to 4 kWat the fan shaft.

12.7.2 Fan and motor assemblies over 2.5 kW inputpower shall have separate adjustable twin 'vee' beltdriven systems.

12.8 REFRIGERATION EQUIPMENT

12.8.1 Refrigeration equipment shall be inaccordance with Section Two—Refrigeration Plant ofthis Specification.

12.9 HUMIDIFIERS

12.9.1 Humidifiers shall be fitted where indicated,and be of the electrode boiler, quartz infra-red,ultrasonic or other approved type. Water supply,

overflow and trapped drain connections shall beprovided. Assemblies shall be as described in SectionSix— Humidifying Plant of this Specification.

1 2 . 1 0 HEATERS

12.10.1 Heaters shall be hot water or electric typeas indicated and shall comply with the requirementsof Section Five -Air Heater and Cooler Batteries—ofthis Specification, with automatic controlarrangements in accordance with Section Twenty-Three—Automatic Controls of this Specification.

1 2 . 1 1 COOLERS

12.11.1 Coolers shall be direct-expansion or chilledwater type as indicated and shall comply with therequirements of Section Five—Air Heater and CoolerBatteries—of this Specification, with automatic controlarrangements in accordance with Section Twenty-Three—Automatic Controls of this Specification.

12.11.2 Drain trays shall be fitted below headersand cooler coils in accordance with Section Five—AirHeater and Cooler Batteries of this Specification.

12 .12 CONTROLS

12.12.1 An integral air flow switch shall react tofan, motor or drive belt failure by de-energising thecomplete unit and any associated remote humidifierand activate an alarm system as indicated.

12.12.2 Automatic controls shall be arranged asindicated.

12.12.3 A panel shall accommodate a 'HAND/OFF/AUTO' switch, 'RUN' and 'TRIP' indication lamps, andhave a door interlocking mains isolator. A spare fuseand carrier and circuit diagram shall be provided andretained on the inside face of the door. A buildingmanagement system (BMS) interface shall be providedwhere indicated.

1 2 . 1 3 ELECTRICAL REQUIREMENTS

12.13.1 Units shall be suitable for continuousoperation and shall comply with the requirements ofDEO Specification 034.

October 1997 53


Section Thirteen—Water Pumps

13.1 GENERAL

13.1.1 Values of resistance to fluid flow of items ofequipment, pipework and/or the total distributionsystem, are indicated for tender purposes only.

The Contractor shall obtain and use manufacturers'certified values of resistance to fluid flow of allequipment items and fittings which comprise the totaldistribution system indicated, to provide pumpscapable of delivering the required volume whenoperating against the total resistance calculated fromthis data and the pipework resistance. Changes insystem arrangement or pipe sizes shall also becompensated for.

Where appropriate pumps shall include for availablenet positive suction head (BS 5316: Part 1) and forstatic lift, eg. for condenser cooling water pumps atcooling towers.

13.1.2 Pumps shall be installed in accordance withthe manufacturer's recommendations and shall complywith the requirements of BS EN 60335-2-51, BS 4082:Part 1 and Part 2, and BS 5257 as applicable.

13.1.3 Pumps shall be 'type' tested in accordancewith BS 5316: Part 1. Pump curves shall be submittedto indicate performance under all likely operatingconditions.

13.1.4 Close-coupled pumps shall be arranged suchthat the failure of a pump seal shall not result indamage to the drive motor.

13.1.5 Floor mounted pumps shall be set on aprepared base not less than 300mm high incorporatinganti-vibration inserts and foundation bolt pocketsconstructed by the Building Contractor to informationprovided by the Contractor in accordance with SectionTwenty-One—Vibration Isolation and Noise Insulationof this Specification. Pumps shall be properly levelledand aligned before final fixing down.

13.1.6 Pump connections shall be screwed to BS 21for sizes up to 50mm and flanged to BS 4504 to suitthe system maximum pressure on sizes 65mm andabove.

13.1.7 Connecting pipework shall be arranged toensure that no stresses are transmitted to pumpcasings.

13.1.8 Each pump shall be fitted with an isolatingvalve on suction and discharge connections.

13.1.9 Pumps shall be complete with a drain plugand, except where the pump is inherently self-venting,an air release cock.

13.1.10 Unless otherwise indicated, pump shaftspeed shall not exceed 24 rev/s.

13.2 CENTRIFUGAL PUMPS

13.2.1 Pumps shall comply with BS 4082 or BS5257 as appropriate. Shafts and impellers shall becorrosion resistant. Shaft extensions shall have aliquid shield. Cast iron casings shall not be subjectedto a pressure in excess of 15 bar gauge. Impellersshall be balanced to Balance Quality Grade G6.3 ofBS 6861: Part 1.

13.2.2 Pumps installations shall include suctionand discharge taper pieces where necessary. Packedgland wells shall be piped to a drained open tundishadjacent to the pump base.

13.2.3 Unit-constructed close-coupled pumps shallbe of the back pull-out type, enabling the motor, driveand impeller to be withdrawn from service withoutdisturbing the volute casing, connections, piping, etc.

13.2.4 Direct-driven pumps and their drive motorsshall be mounted on a common bedplate.

13.2.5 In-line pumps shall be fitted withmechanical seals unless otherwise indicated. Eccentricreducers or taper pieces shall be fitted at suction anddischarge connections where pump connection sizes

54 October 1997


Section Thirteen—Water Pumps

differ from pipeline size. Pumps shall be suitable formounting on a prepared base with foundation bolts oron wall brackets.

13.3 TWIN PUMP SETS

13.3.1 Twin pump sets shall comprise direct-coupled in-line pumps connected in parallel withcommon inlet and outlet connections. The assemblyshall incorporate non-return check valves to isolatethe stationary pump. Twin pump sets shall be suitablefor mounting on a prepared base with foundation boltsor on wall brackets. Impeller and motor assembliesshall be readily removable and a blanking flange shallbe provided.

13.4 CANNED ROTOR PUMPS

13.4.1 Canned rotor and glandless pumps up to2kW input power shall comply with BS EN 60335-2-51and BS 1394: Part 2.

13.5 STAND-BY PUMPS

13.5.1 Where stand-by pumps are indicated withautomatic change-over, the change-over shall beinitiated and verified by means of flow sensing devicesof an approved pattern. Non-return check valves shallbe incorporated in each discharge line.

13.6 GAUGES

13.6.1 Each pump shall be provided with twopressure gauges, one connected to the suction side andone to the discharge side. Where stand-by pumps are

installed, one pair of gauges shall be so connectedwith isolating cocks that the pressure head of eachpump can be read. Gauges shall be in accordance withSection Twenty-Two—Instruments—of thisSpecification and shall be mounted in an accessibleposition.

13.7 DRIVES

13.7.1 Pumps shall be driven by electric motorswhich shall be in accordance with Section Twenty-Five—Electrical Equipment and Wiring—of thisSpecification and shall be direct-driven or belt-drivenas indicated. Pump drive arrangements shall be inaccordance with Section Twenty—Belt Drives, VariableSpeed Drives and Guards—of this Specification.Electrical connections to motors shall be in accordancewith Section Twenty-Five of this Specification.

13.8 SUMP PUMPS

13.8.1 Each pump shall be protected by aremovable non-ferrous strainer on the suction. Suctionlift pumps shall terminate with a foot valve ofdiameter not less than the pipework. Sump pumpsshall operate automatically under level control withprovision for an alarm to indicate when normal highwater level is exceeded.

13.8.2 Submersible and submerged pumps shall becomplete with high and low level controllers, controlpanel, lifting handle and chain and guide rails asnecessary. Studs, bolts, nuts, screws and washers shallbe stainless steel.

October 1997 55


Section Fourteen—Pipework

14.1 GENERAL

14.1.1 Pipework for chilled water, condenser waterand condensate drainage systems shall be in accordancewith Table 14A of this Specification. Pipework forrefrigerants shall be in accordance with Section Two—Refrigeration Plant—of this Specification. Requirementsfor all other pipework system shall be in accordancewith DEO Specification . The word 'size', when relatedto pipework, shall mean the nominal size whichgenerally approximates to the bore of steel tubes andthe outside diameter of copper tubes.

14.1.2 Pipework designated as 'concealed' in Table14A of the Specification and elsewhere shall includeall pipework in chases, ducts, service shafts,partitions, ceiling voids and floors. It shall not includeshort lengths of pipework passing through thebuilding structure.

14.2 MATERIALS

14.2.1 Tubes, pipes and fittings shall be asindicated with detailed requirements in accordancewith Table 14A of this Specification.

14.2.2 Steel pipework shall be black except for thefollowing which shall be galvanised:

a) open condenser water system pipework,

b) drain pipework,

c) vent pipework,

d) overflow pipework,

e) other systems as indicated.

14.2.3 Where used, exposed threads of screwedgalvanised pipe shall be painted with 'cold galvanising'solution. Galvanising shall conform to therequirements of BS 1387, Appendix A—CopperSulphate Test. Where sections of flanged galvanisedpipework and fittings are site-fabricated, black pipe

and fittings shall be used, assemblies being returnedto works for galvanising to the standard indicatedafter fabrication.

14.2.4 All copper tube supplied for use shall havecertification that it conforms to the requirements ofBS EN 1057 and that it is:

a) round, clean, smooth and free from harmfuldefects and films in the bore,

b) free from any carbonized layer which mayhave been left in the bore of the tube bydrawing lubricants,

c) supplied by one manufacturer (any change ofmanufacturer must receive the approval of thePM and new certificates shall be provided forsubsequent manufacturers' supplies).

14.3 JOINTS

14.3.1 Screwed joints in galvanised pipework shallhave taper threads.

14.3.2 Joints in all concealed steel pipework and inall steel pipework above DN 100 size shall be welded.Joints in all concealed copper pipework shall bebrazed. All other pipework sizes may have screwed orwelded joints except under Clause 14.3.14.

14.3.3 Where screwed joints are used, unlessotherwise indicated, the male end shall be taperthreaded to BS 21 and the jointing material shall bePTFE tape to BS 6956: Part 5 and BS 7786.

14.3.4 Screwed fittings shall be of malleable castiron to BS 143 & 1256 and BS EN 10242 with bandedor beaded reinforcement.

14.3.5 Welding fittings shall be to BS 1965.

14.3.6 Flanges for steel pipework shall have raisedfaces to BS 4504: Part 3, Table 9, and shall bemachined over the face. Where flanged joints are to bemade to an existing installation having flanges of

56 October 1997



Imperial sizes, the mating flange shall be flat faced toBS 10 and shall be appropriate to the system workingpressure.

14.3.7 Where flanged connections are made tocopper alloy valves with flat faced flanges, the raisedface of the steel flange shall be removed and theresulting machined face shall comply to the tolerancesallowed in BS 4504: Part 3.2.

14.3.8 Metric bolts of the correct diameter shall beused with flanges to BS 4504.

Where Imperial bolts are unobtainable for use withexisting Imperial flanges, Metric bolts shall be used asfollows:

14.3.9 Flanged joints shall be made with gaskets toBS 4865: Part 1 or BS 3063 as appropriate, with gradeand thickness suitable for the service conditions.

14.3.10 Proprietary grooved pipe jointing systemsusing elastomeric seal rings may be used, with theapproval of the PM, up to a maximum pressure of 9.5bar gauge. Such jointing systems shall be suitable forthe temperature, pressure and operating conditions ofthe service. The manufacturer's recommendations onpipe wall thickness, methods of groove forming (cut orrolled), groove dimensions, seal materials and limitingoperational loads shall be followed. Piping ends shallbe within the recommended tolerances and shall befree from burrs and distortion. Provisions to maintainelectrical continuity at all joints shall be made.

14.3.11 Flanges for steel pipework shall be of forgedsteel. Headers shall be of flanged steel tube withflanged outlets welded on. Spare outlets shall beblanked with bolted flanges.

14.3.12 Plastics pipework joints between pipe andfittings shall be made by the solvent welding process.No cleaning fluid other than that supplied orrecommended by the pipe manufacturer shall be used.

14.3.13 Joints in plastics pipework to equipmentitems shall be flanged unless otherwise indicated.Joints shall be made with a socket flange of the fullface type or stub type, fixed to the pipe by the solvent

welding process and with a loose metal backing ring.The flange and ring shall be drilled to match themating flange and the joint shall be made with aneoprene or similar gasket.

14.3.14 At dismantling points and connections toappliances, the joints in steel pipework shall be madewith spherical seated unions up to DN 50 size andwith flanges for 65mm size and above. For copper andplastics pipework up to 65 size, union connectors maybe used.

14.4 FLEXIBLE PIPING CONNECTIONS

14.4.1 Where required for final connections toequipment, flexible piping with integral screwed orscrewed union connectors at each end shall beprovided and the whole assembly rated for thepressure and temperature conditions of the system.

14.4.2 Connections shall be arranged in long radiussweep bends as applicable and shall not exceed DN600 in length without the approval of the PM.

14.4.3 Piping shall be woven mesh reinforced toprevent kinking and restriction of bore, and shall haveadequate support.

14.4.4 Connections shall only be fitted betweenitems of identical diameter. No bushing or otherreduction in bore shall be made.

14.5 FLEXIBLE CONNECTORS

14.5.1 Flexible connectors shall be provided whereindicated and be suitable for all system operatingconditions.

14.5.2 Connectors shall be soft spherical formneoprene rubber joints with reinforced convolutions.They shall achieve a high vibration isolation efficiency,have noise absorbing properties and be of the tiedbellows type suitable for the system test pressure.

14.5.3 Backing flanges shall be mild steel ofappropriate pressure rating for the system(s).

14.6 WELDING

14.6.1 Unless otherwise indicated, steel pipeworkcomplying with BS 1387 or BS 3601 not exceeding DN200 size and 20mm wall thickness shall be welded inaccordance with the recommendations in HVCA/JIBRecommended Practice (formerly HVCA Code ofPractice TR/5), as modified below. Steel pipes of larger

October 1997 57



diameters and greater thicknesses shall be welded inaccordance with BS 2971, BS 2640, or otherspecifications as indicated or approved by the PM.

14.6.2 Joint designs, welding procedures, weldercertification and production weld quality shall complywith the requirements as interpreted by the appointedInspection Body.

14.6.3 Unless otherwise indicated, joint designs,welding procedures and welders' competency testsshall be as described in HVCA/JIB RecommendedPractice (formerly HVCA Code of Practice TR/5). Priorapproval shall be obtained for the installation ofgusseted bends.

14.6.4 Welders shall hold current certificates ofcompetency validated by the appointed InspectionBody, or similar approved body. Welders withoutvalidated current certificates shall undertake therelevant standard tests, witnessed and certified by theappointed Inspection Body before commencing work.Welders with validated certificates who lack relevantwelding work experience in the preceding 3 months,and other welders as directed by the PM, shallundertake the relevant tests witnessed and certifiedby the appointed Inspection Body before commencingwork.

14.6.5 Each welder shall permanently identify eachof their welds with a marker which will withstand siteconditions without damaging system or componentperformance. Methods of marking shall be approved.

14.6.6 Unless otherwise indicated, welds shall besubjected to a programme of non-destructive testing inaccordance with the relevant Standard. The method oftesting shall be ultra-sonic or radiographic inaccordance with BS 3923 or BS 2910 respectively, asapproved by the PM. The testing shall be carried outby certified competent persons recognised by theappointed Inspection Body. Copies of the test reportsshall be given to the appointed Inspection Body andthe PM at times which permit adequate considerationwhilst the relevant welds remain exposed. The NDTprogramme shall include:

a) testing one of the first five production weldsmade by each welder,

b) testing 10% of the subsequent productionwelds made by each welder,

c) in the event of finding a faulty weld, at thediscretion of the PM, the testing of a furthertwo welds made by the relevant welder.

14.6.7 The welds tested in compliance with Clause14.6.6 shall be as randomly selected by the PM.

14.6.8 Welds found to be defective shall be rectifiedto a standard complying with BS 2971 or BS 2640 tothe satisfaction of the appointed Inspection Body. Atthe discretion of the PM rectification work shall becarried out by different welders. At the discretion ofthe PM welders with failure rates considered excessiveby the appointed Inspection Body shall be taken offthe Works.

14.7 BRAZING

14.7.1 Copper pipework up to 200m size with wallthicknesses up to 4.5mm shall be brazed in accordancewith the recommendations of HVCA/JIBRecommended Practice (formerly HVCA Code ofPractice TR/3), as modified below. For other pipe sizesand thicknesses, brazing shall be carried out inaccordance with BS 1723, or other specification asindicated or approved by the PM.

14.7.2 Joint designs, brazing procedures, brazercertification and production joint quality shall complywith the requirements as interpreted by the appointedInspection Body.

14.7.3 Unless otherwise indicated or approved,filler metal shall be AG2 as specified in BS 1845.

14.7.4 Brazing procedures shall include auxiliaryheating for pipes 76mm size and larger, for solidcopper flanges, and in other circumstances whereexposure, weather, wall thickness etc, indicate soundjoints will not be otherwise assured.

14.7.5 Brazers shall hold a valid certificate ofcompetency issued by the appointed Inspection Bodyor similar approved body. Unless otherwise indicated,the (formerly TR/3) standard test piece will be theaccepted test of competency. Brazers without validcertificates and those without relevant brazing workexperience within the preceding 3 months shallundertake the (formerly TR/3) test, witnessed andcertified by the appointed Inspection Body, beforecommencing work.

14.7.6 Each brazer shall permanently identify eachof their joints with a marker which will withstand siteconditions without damaging system or componentperformance. Methods of marking shall be approved.

14.7.7 A proportion of the joints made by eachbrazer each day, as indicated, shall be cut out andsubjected to destructive testing under the supervisionof the appointed Inspection Body. In the event of

58 October 1997



finding a faulty joint, a further two joints made by therelevant brazer shall be cut out and tested. Jointsshall be selected for test at the discretion of the PMup to the numbers indicated. Cutting out andconsequential repair works shall be carried out by theContractor at his expense.

14.7.8 Visual examination and destructive testingof joints will be carried out by the appointedInspection Body during the system pressure tests. Thetest criteria shall be those stated in HVCA/JIBRecommended Practice (formerly HVCA TR/3).

14.7.9 At the discretion of the PM rectificationwork on faulty joints shall be carried out by differentbrazers. At the discretion of the PM brazers withfailure rates considered excessive by the appointedInspection Body shall be taken off the Works.

14.8 ANCILLARY EQUIPMENT

14.8.1 Pipework supports

14.8.1.1 Pipework shall be supported adequately andin such a manner to accommodate thermal movement.Pipework supports shall be arranged as near aspossible to joints, and the centre spacings shall notexceed those given in Tables 14B, 14C and 14D of thisSpecification. Where there are two or more sizes ofpipes, the common support spacings shall be thoserequired for the smallest bore. The weight, method ofsupporting pipework, together with the thrust atanchor points is to be approved by the PM.

14.8.1.2 Centre spacing for plastics pipeworksupports shall not exceed those given in Table 14D ofthis Specification, unless otherwise indicated.

14.8.1.3 Vertical rising piping shall be supported atthe base, or as indicated, to accept the total weight ofthe riser. Branches from vertical pipework shall not beused as a means of support for risers.

14.8.1.4 Brackets for mild steel pipework shall bemild steel or malleable iron with ferrous fixings.Brackets for copper pipework shall be brass orgunmetal with non-ferrous fixings.

14.8.1.5 Where pipework up to DN 50 is fixed tosolid walls, brackets may be of the screw-on or longshank built-in type, except where the walls areplastered, where only the long shank built-in typeshall be used. For fixing to woodwork and lightweightpartitions or walls, screw-on pattern and adjustabletwo-piece type are acceptable. The detachable part of apipe clip shall be capable of removal withoutdisturbance of the fixing or adjacent pipes.

14.8.1.6 Brackets screwed to walls shall be securedby expanding plugs or other purpose-designed fixingdevices. Wooden plugs will not be permitted.

14.8.1.7 Suspended pipework subject to thermalmovement shall be mounted on swivel hangers unlessotherwise approved by the PM.

14.8.1.8 Hangers for horizontal pipework at highlevel shall be supported from mild steel angle orchannel sections, supplied by the Contractor, suitablefor building-in or otherwise fixing to the structure bythe Building Contractor. Welding to the structure shallnot be undertaken without prior approval of the PM.Adjustable mild steel hangers shall be used. Pipe ringsshall be malleable cast iron or fabricated steel, madein halves and secured by bolts and nuts or set screws.Alternatively, malleable iron hinged pipe rings may beused. Calliper hooks will not be permitted. Proprietarypipework suspension systems may be used with theapproval of the PM.

14.8.1.9 Where pipework is fitted in ducts ortrenches, the pipe supports shall be of the typeindicated, and, where appropriate, shall allowclearance to permit insulation to be applied to therequirements of Section Seventeen—ThermalInsulation—of this Specification.

14.8.1.10 Load bearing insulation at supportsincorporating a vapour barrier, shall be fitted by theContractor at the time of pipework installation toensure continuity of the overall vapour barrier.

14.8.2 Anchors

14.8.2.1 On mild steel pipework, mild steel anchorscapable of resisting the maximum stresses shall beprovided and preferably shall be welded to thepipework. Where it is impracticable to weld theanchors to the pipework, cast-iron chairs with at leasttwo wrought-iron stirrup bolts shall be used, the boltsbeing provided with sufficient thread to ensure aneffective grip on the pipe. For copper pipework, theanchors shall be provided by wide copper strapssecured to the pipework in such a manner that thepipe is not damaged. The Contractor shall supply, andlocate in positions for building-in, all cleats, bracketsand steelwork required for anchor points. Steelworkfixed in trenches or ducts to which anchors areattached shall be hot-dip galvanised. Anchors attachedto pipework shall be cleaned and finished with twocoats of aluminium paint.

October 1997 59



14.8.3 Expansion devices

14.8.3.1 All provisions for thermal movement shallbe made in accordance with the requirements of DEOSpecification 036

14.8.4 Air vents

14.8.4.1 Devices for air venting shall be provided atthe high points of the sections which they areintended to vent.

14.8.4.2 Air bottles shall be of welded construction.On pipework up to and including DN 80 size, eachbottle shall be manufactured from DN 50 size tube300mm long with a cap. Air bottles on pipework DN100 size and over shall be manufactured from DN 100size tube, each 380mm long with a cap, directlyconnected to the system pipework. All air bottles shallbe complete with a DN 15 size galvanised air releasetube extended from the top to a position approved bythe PM within 1.5m of the floor and fitted with a DN10 size needle-seated globe valve or air cock.

14.8.4.3 Automatic air vents shall be used onlywhere indicated. They shall have malleable iron,nodular iron, gunmetal or brass bodies as indicated,with non-ferrous or stainless steel floats and guidesand non-corrodible valves and seats and be suitablefor the system temperature and pressure. Eachautomatic air vent shall be controlled by a lock-shieldvalve . Air release pipes shall be run to discharge atthe nearest suitable visible safe point to the approvalof the PM.

14.8.4.4 Air venting devices and any air releasepipes installed in exposed positions where freezing islikely to occur, shall be insulated in accordance withSection Seventeen—Thermal Insulation—of thisSpecification.

14.9 DRAINING AND FLUSHING PROVISIONS

14.9.1 Key operated drain cocks, of the sizeindicated with hose unions shall be fitted to the lowestaccessible points of the system pipework and also onindividual items of plant to ensure complete drainage.Where pipes run under doorways, and for similarshort sections of pipework which do not drain to thesystem low points, DN 15 size plugged-outlet teesshall be supplied and fitted.

14.9.2 Provision shall be made for flushing ofpipework. These provisions shall include:

a) Self-draining section: The pipework systemsshall be sub-divided into self-drainingsections. Such sections shall be fitted withdrains of the straight-through type, egquarter-turn plug cocks, ball valves, butterflyor gate valves of line size up to DN 40diameter, and DN 50 minimum for all largerpipe sizes. Full-bore dirt pockets at least 5diameters in length, complete with full-boreisolating valves, shall be provided at the baseof each riser. Each dirt pocket shall have adrain valve of at least DN 25 size.

b) Air vents: Manual air vents of minimum sizeDN 25 connected to large-bore air bottles,shall be installed at high level on each self-draining section.

c) By-passes: Provision shall be made for flexibleor fixed full-bore by-passes to be fitted acrossall major items of plant in order to facilitatethe circulation of water during dynamicflushing operations.

d) For pipework sizes exceeding 200mm,provision shall be made, where indicated, forflexible or rigid lance water jetting. Flangedmake-up tee pieces (minimum one), tofacilitate entry into the system, shall be fittedat intervals not exceeding 100m.

e) Items which could be damaged by the flushingand cleaning process shall be isolated andcleaned by approved alternative methods.

14.9.3 On completion of pre-commissioningcleaning, and before final filling, the flushingconnections shall be finally closed with bolted blankflanges and the drain valves locked in the closedposition.

14.9.4 For chemical cleaning of pipework systemssee Clauses 14.12.2 to 14.12.5.

1 4 . 1 0 INSTALLATION

14.10.1 All pipework shall be subject to theinspection and tests specified. No coating or coveringshall be applied until all inspections and tests arecompleted to the satisfaction of the PM.

14.10.2 Unless otherwise indicated, steel and copperpipework systems shall be designed and installed inaccordance with BS 806 and BS 1306 respectively.

14.10.3 Where services require the connection ofdifferently sized items, the Contractor shall provideand install eccentric reducers or taper pieces.

60 October 1997



14.10.4 Joints shall not be made in the thickness ofany wall, floor or ceiling. Pipework shall not beembedded in the structure of floors unless otherwiseapproved by the PM. Where pipework passes throughwalls, floors or ceilings, sleeves shall be provided oneach pipe. The sleeves shall be of the same material asthe pipe. Pipework passing through floors shall beprovided with approved floor and ceiling platesfastened securely to the pipe. Pipes passing through astructure which is a fire separation with a designatedfire resistance to BS 476: Part 22, shall have a fire-stop sleeve in accordance with the requirements of theBuilding Regulations. Steel sleeves in plant roomfloors shall be galvanised. All sleeves in plant roomfloors shall extend 50mm of the finished floor level.

14.10.5 Pipe sleeves set in external walls, floor slabsand roofs shall be sized to provide 15mm clearancearound the pipe to be installed or, where the pipe is tobe thermally insulated or otherwise covered, 15mmclearance around the covering surface in order that thesleeve may be packed with mineral fibre and sealed atboth ends with a water and fire-retardant mastic.Alternatively, a proprietary fire-retardant sealingprocess shall be employed at the discretion of the PM.

14.10.6 Roof sleeves shall be provided with water-shedding external cowls fitted to the pipe.

14.10.7 Where pipework enters the building througha large hole or duct, a mild steel blanking plate notless than 6mm thickness shall be built into the wallsof the building or duct. The pipework shall penetratethe blanking plate by passing through the requirednumber of clearance sockets, each of length not lessthan 4 pipe diameters, welded into openings in theblanking plate. The space between each clearancesocket and the pipe shall be packed and sealed inaccordance with Clause 14.10.5.

14.10.8 Fittings shall be of the same size as thetubes and pipes to which they are connected.Exceptionally, where a fitting having the requiredoutlet is not of standard manufacture, the necessarysize reduction may be accomplished by the use of onebush for each connection.

14.10.9 Galvanised fittings shall be used only ongalvanised pipework.

14.10.10 Unless otherwise indicated, malleablefittings to BS 143 & 1256 and BS EN 10242 shallcomply with the following:

a) Elbows to ISO Code Al shall be used inpreference to bends to ISO Code Dl.

b) Tees to ISO Code Bl shall be used inpreference to pitcher tees to ISO Code El.

14.10.11 Eccentric reducing sockets (ISO Code M3),shall be used where changes of bore are made in runsof nominally horizontal pipework.

14.10.12 Pipework shall follow the contours of walls.The clearance between pipework, fittings, insulationor flanges, and the wall or any other fixtures, shall benot less than 25mm.

14.10.13 Purpose-made bends or springs may be usedwhere it is necessary to deviate from a straight run inungalvanised pipework. In galvanised pipework, suchdeviations shall be formed from standard fittings.

14.10.14 Bends or springs in DN 50 size tube andabove shall be hot-pulled and the tubes shall remaincircular after setting.

14.10.15 Bends, springs and sets in copper tube toTable X of BS EN 1057 and with sizes up to andincluding 42mm, may be site-fabricated wherestandard fittings cannot be used, or where thismethod will give a neater appearance. Pulled bends oroff-sets which show flattening, ripples or constrictionof bore, will be rejected. Fittings of sizes 6mm to67mm shall be capillary type with integral solderrings, or non-manipulative compression type, all to BS864: Part 2 and all resistant to dezincification.Fittings of sizes 76mm and 108mm shall be flangedcompression type or capillary type. Fittings for copperpipework above 108mm size shall be flanged, brazedor bronze welded.

14.10.16 Fittings for plastics pipework shall be of thesame materials as the pipework to which they arejointed. They shall be made or recommended by thepipe manufacturer, and be suitable for the solventwelding process. Where screw threads are required, aproprietary threaded adaptor fabricated fromheavyweight tube shall be used.

14.10.17 Where springs are required in plastics piperuns, the pipe shall be pre-softened by use of heatedbrine, glycerine oil or water as recommended by thepipe manufacturer. On no account shall a naked framebe applied to the pipe surface.

14.10.18 Before pipework is assembled, theContractor shall ensure that tubes and tube ends arefree from burrs and cutting dross. Tube ends shall bethoroughly cleaned of all harmful materials such asrust, scale, paint, oil, etc. During the progress of work,

October 1997 61



open ends shall be closed temporarily with purpose-made metal, close-fitting plastics or wood plug or caps,or blank metal flanges.

14.10.19 Arrangement of headers where requiredshall be in accordance with DEO Specification 036.

14.10.20 Pipework shall be arranged with adequatejointing to allow ease of dismantling.

14.10.21 All metallic pipework systems shall be bondedin accordance with BS 7671. Electrical continuity shallbe maintained at all joints in every system.

14.11 PROVISION FOR TESTS

14.11.1 Self-sealing test points

14.11.1.1 Where indicated, self-sealing test pointssuitable for temperature and/or pressure testing shallbe provided. One thermometer and one pressure gaugefor each range of temperatures and pressures, suitablefor use with the test points, shall be packed in aprotective casing and handed to the PM together withan adequate supply of any necessary insertionlubricant. Test points shall be fitted with captive capsand have internal self-sealing devices. The test pointsand probes shall be of materials suitable for theapplication.

14.11.2 Thermometer pockets

14.11.2.1 Thermometer pockets shall be provided andinstalled in pipeline services in accordance with SectionTwenty-Two—Instruments—of this Specification.

14.11.3 Pressure tappings

14.11.3.1 For each air conditioning installation with atotal design cooling capacity in excess of 30kW, and foreach shell and tube evaporator, condenser and coolingtower of duty in excess of 70kW, valved pressuretappings suitable for connection of a pressure gaugeshall be fitted to the flow and return connections.

14.11.3.2 Alternatively, or where indicated, isolatingvalves with pressure test fittings, as specified inSection Fifteen—Valves, Cocks and Strainers—of thisSpecification, may be used in lieu of valved pressuretappings in Clause 14.11.3.1.

14.11.4 Flow rate metering

14.11.4.1 For each chilled water air conditioningsystem, an assembly consisting of an orifice plate andtwo valved pressure tappings for manometer tubes,

shall be installed in the main chilled water pipe andin other locations where indicated. Alternativelyventuri metering devices with valved pressuretappings may be provided.

14.11.4.2 The orifice plate shall be of stainless steeland the resistance to flow at the design rate shall notexceed 4.5 kPa. Installations shall provide 10 pipediameters (minimum) upstream and 5 pipe diameters(minimum) downstream of straight pipe, or asrecommended by the manufacturer.

14.11.4.3 Each orifice plate shall be permanentlymarked with the direction of flow and the diameterand type of the orifice. This information shall beclearly visible beyond any flanges or insulation whenthe orifice plate is installed in the pipeline. Unlessotherwise indicated, the orifice plates shall be carrier-ring mounted with corner tappings.

14.11.4.4 Flow rate metering installations shall beprovided in other locations indicated.

14.11.4.5 All metering devices shall be provided witha permanent means of identification which includesdesign flow rate and related pressure dropinformation. Metering devices and methods shallcomply with the requirements of BS 1042.

14.12 PROVISION FOR CHEMICAL CLEANING ANDWATER TREATMENT

14.12.1 Water treatment for ferrous pipeworksystems shall be in accordance with SectionEighteen—Water Treatment—of this Specification. Forchemical cleaning requirements see ParticularSpecification.

14.12.2 Cleaning procedures shall be carried out inaccordance with the recommendations contained inCIBSE Commissioning Code 'W and the 'Code ofPractice for the use of High Pressure Water JettingEquipment' published by The Association of HighPressure Water Jetting Contractors.

14.12.3 Where sections of the pipework systems arerequired to be separately pre-operation cleaned, theContractor shall provide and install all necessary by-passconnections and loops to facilitate positive circulationthrough the section of the systems to be cleaned.

14.12.4 The Contractor shall be responsible forensuring that all air vents, solution tanks, dosing potsand drain valves necessary for the proper dosing,venting, circulation and draining of the systems forwater treatment purposes are installed and

62 October 1997



operational, and that circulating pumps are availablefor duty before any chemicals are introduced into thesystems.

14.12.5 The Contractor shall make all arrangementsfor the safe disposal of all chemicals used in pipecleaning operations

TABLE 14A: SELECTION TABLE FOR TUBES AND PIPES FOR CHILLED WATER, CONDENSER COOLING WATER AND CONDENSATEDRAINAGE INSTALLATIONS

denotes permitted selection *see Clause 14.1.2

October 1997 63



TABLE 14B INTERVALS BETWEEN SUPPORT CENTRES FORSTEEL PIPEWORK

TABLE 14D INTERVALS BETWEEN SUPPORTCENTRES FORPLASTICS PIPEWORK (Contents not exceeding 20°C)

Sizemm

1520253240506580

100125150200250300

Intervals forHorizontal Runs

Barem

1.82.42.42.73.03.03.73.74.04.55.58.59.0

10.0

Insulatedm

1.82.42.42.42.42.43.03.03.03.74.56.06.57.0

Intervals forVertical Runs

Bare orInsulated m

2.43.03.03.03.73.74.64.64.65.55.58.59.0

10.0

Pipe0/Din

1

11/411/4234681012


m

0.91.01.01.11.21.31.61.92.12.42.62.8


m

1.31.51.51.61.81.92.42.83.03.63.94.2

TABLE 14C INTERVALS BETWEEN SUPPORT CENTRES FORCOPPER PIPEWORK

Sizemm

1522283542546776

108133159


Barem

1.21.21.82.42.42.73.03.03.03.74.5

Insulatedm

1.21.21.51.81.81.82.42.42.43.03.7


Bare orInsulated m

1.81.82.43.03.03.03.73.73.73.73.7

64 October 1997


Section Fifteen—Valves, Cocks and Strainers

15.1 GENERAL

15.1.1 This section relates to valves, cocks andstrainers used with chilled and condenser waterdistribution. Items used with other piped servicesshall be provided in accordance with DEOSpecification 036.

15.1.2 Valves shall be easily accessible. Valvesfitted in horizontal pipework or to equipment withhorizontal connections, shall be installed with thevalve spindle vertically upwards unless other agreedby the PM. Check valves shall be installed inaccordance with the manufacturer's recommendations.

15.1.3 Where indicated, valves or cocks shall belockable, with purpose-made locking devices which donot impede the fast closure of the valve where that isnecessary. The locking device shall remain attached tothe valve in both 'open' and 'closed' positions.

15.1.4 All valves and strainers shall have themanufacturer's name, pressure rating and size clearlymarked on the outside of the body. Additionally, allglobe and check valves and strainers shall havepermanent indication of flow direction.

15.1.5 Loose keys for plug type and lock-shieldvalves, shall be provided and handed to the PM asindicated.

15.1.6 Where modifications or extensions to existingservices are to be carried out, all valves which are to beremoved and re-fixed shall be over-hauled thoroughly,with glands and seals renewed, all to the satisfaction ofthe PM.

15.2 MATERIALS AND CONSTRUCTION

15.2.1 Unless otherwise indicated, copper alloyshall mean one of the alloys specified in BS 5154suiting the application.

15.2.2 Bodies of valves and cocks up to andincluding 50mm size shall be copper alloy. Bodies ofvalves and cocks 65mm size and larger shall be copperalloy or cast iron as indicated.

15.2.3 Valves and cocks in steel pipework up to andincluding 50mm size shall have threaded ends to BS21, and those of 65mm size and above shall haveflanged ends to BS 4504.

15.2.4 Gland packing, plug lubricants etc, shall besuitable for the application. Exfoliated graphitepacking shall not be used in steel components.

15.2.5 Copper alloy valves shall be resistant todezincification.

15.3 ISOLATING VALVES

15.3.1 Isolating valves on flow connections toequipment shall be as indicated with hand-wheels.Valves on return connections shall be of the doubleregulating type complying with Clause 15.5.2.

15.3.2 Valves shall be selected from the followingtypes:

a) cast iron globe valves to BS 5152,

b) copper alloy globe valves to BS 5154,

c) cast iron wedge gate valves to BS 5150,

d) cast iron gate (parallel slide) valves to BS5151,

e) copper alloy gate valves to BS 5154,

f) cast iron butterfly valves to BS 5155,

g) cast iron ball valves to BS 5159,

h) cast iron lubricated plug valves to BS 5158.

15.3.3 Butterfly, ball and plug valves shall beoperated either directly or indirectly as indicated.

October 1997 65



15.4 CHECK VALVES

15.4.1 Check valves shall be installed as indicatedand be in accordance with either BS 5153 for cast ironvalves or BS 5154 for copper alloy valves.

15.5 REGULATING AND DOUBLE REGULATING VALVES

15.5.1 Regulating valves complying with BS 5152or BS 5154 as relevant shall have characterised plugsto give a linear or equal percentage characteristic andmicrometer indicators or indicators of the type wherea pointer moves over a scale permanently fixed to themain structure of the valve.

15.5.2 Double regulating valves shall comply withClause 15.5.1 and incorporate a facility to preventopening beyond preset limits.

15.5.3 Valve body material and type of endconnections shall be in accordance with therequirements for valves detailed in Clauses 15.2.2 and15.2.3 as appropriate.

15.5.4 All regulating valves shall be sized for thepressure drop as indicated.

15.6 SYSTEM COMMISSIONING VALVE SETS

15.6.1 Measuring devices shall provide flowmeasurement accuracy to within + 5%, or asindicated, under the service conditions to be expected.Measuring devices shall be selected for particularapplication such that the differential pressureproduced is consistent with achieving measurementaccuracy.

15.6.2 Commissioning sets for balancing waterflows between circuits shall comprise the following asindicated:

a) Measuring devices comprising oblique globevalves, complying with BS 5152 or BS 5154 asrelevant, intended and calibrated for use inthe fully-open position, installed at theupstream ends of circuits, and with regulatingdevices at the downstream ends.

b) Fixed orifice plates generally in accordancewith BS 1042 and isolating valves installed atthe upstream ends of circuits, and withregulating devices at the downstream ends.

c) Combined or integral measuring/regulatingdevices comprising fixed orifice plates coupledto regulating devices installed at thedownstream ends of the circuits and isolatingvalves at the upstream ends.

d) Variable orifice double regulating valves to BS7350 oblique pattern globe valves withcharacterised throttling disk and two pressuretest valves.

15.6.3 Pressure test fittings shall enable safe,positive quick-coupling and uncoupling of the flexibleconnections from the differential pressure indicators.

15.6.4 The regulating devices shall be doubleregulating valves complying with Clause 15.5.2selected for particular application such that requiredflow rates are achieved with valve positions more than25% open.

15.6.5 Automatic temperature control valves shallbe installed in accordance with manufacturer'srecommendations and shall be protected by a pipelinestrainer and isolating valves where indicated.

15.7 DRAIN VALVES

15.7.1 Drain valves shall be provided at the bottomof every riser and at the outlet of major equipmentitems on the 'dead' or 'equipment' side of isolatingvalves and at all low points of pipework.

15.7.2 Drain valves shall be of the screwed end,solid wedge disc, inside screw, non-rising stem,screwed-in bonnet lock-shield type bronze gate valvesto BS 5154 with hose union connector.

15.7.3 Extended drain lines shall be of the samesize as the drain valve. Drain valves sizes shall be:

Main Pipe Size

Up to 40mm

Above 40mm

Drain Valve Size

Line size

50mm

Provisions for rapid draining in connection withpipework system flushing shall be as described inClause 14.9.2.

15.8 AIR COCKS

15.8.1 Air cocks shall be nickel or chromiumplated, of the spoutless pattern and with screwedthread. One loose key shall be provided for each tenair cocks plus one spare.

15.9 VALVE OPERATION

15.9.1 Isolating and double regulating valves shallhave hand-wheels. Regulating valves shall have lock-shield casings. Hand-wheels on bronze bodied gate

66 October 1997



and globe valves shall be of malleable iron, finished inbaked enamel. Hand-wheels on cast iron bodied valvesshall be substantially constructed of cast iron andshall provide ease of operation.

15.10 STRAINERS

15.10.1 Strainers shall be installed to protect heatexchange apparatus, automatic control valves andother sensitive fittings or circuits as indicated.Strainers shall be of the 'Y' pattern unless otherwiseindicated. Strainers shall be suitable for the workingpressures and service of the piping system in whichthey are installed and shall be readily accessible forcleaning.

15.10.2 Strainers shall be screwed or flanged to suitthe isolating valves adjacent to, and on the 'dead' sideof which they are installed and be capable of completeisolation.

15.10.3 Strainer screens shall be of a suitablestainless steel with total area of perforationsequivalent to 250% of pipe cross-sectional area. Thediameter of the perforations shall be in the ranges 0.7-0.9mm and 1.5-1.8mm, for sizes up to 50mm andlarger sizes respectively.

15.10.4 Baskets/screens shall be cleaned with solventafter pre-operational chemical cleaning of pipeworkand shall be thoroughly cleaned again before handover.

15.10.5 Strainer bodies for pipelines up to 50mmsize shall be of copper alloy to BS 1400, PB1, andotherwise of cast iron to BS 1452, Class 180. Strainerpressure ratings shall be at least 150% of maximumservice pressure in the application.

15.10.6 Strainer bodies for pipelines 250mm sizeand above shall be of the cast steel flanged pot-typewith scantlings as for 200mm size.

15.10.7 Duplex type strainers shall be installedwhere indicated.

15.10.8 Self-sealing test points, in accordance withSection Fourteen—Pipework—of this Specification,shall be provided on each side of the strainers.

15.11 VALVE LABELLING

15.11.1 All plant room valves and every circuitcontrol valve shall be provided with a brass, or

approved plastics label 75 x 50 x 1.5mm thick,stamped or engraved with a reference number. Thevalve duty shall be marked on the label except wherea valve chart is provided within the space in whichthe valve is housed. Wherever practicable, the labelshall be affixed to the adjacent structure in aprominent position to identify the valve concerned.Elsewhere, a purpose-made lightweight steel bracketfor carrying the label shall be clamped to the pipeworkadjacent to the valve.

15.11.2 A related circuit control diagram, ordiagrams, schematically setting out the systems shallbe fixed in a position approved by the PM. It shallindicate the position, function, size and referencenumber of all valves, be durable and non-fading, andbe rigidly mounted with an un-breakable andwashable finish.

15.12 VALVE SCHEDULES

15.12.1 Valve schedules shall be prepared in theform of type-written sheets showing the position,function, size, reference number and normal operationsetting of each valve installed.

15.12.2 Valve schedules shall be set out in a logicalorder and the final arrangement of each sheet shall beagreed with the PM before final submission.

15.12.3 One copy of each valve schedule shall besuitably framed and glazed and fixed within the plantroom to which it relates in a position approved by thePM.

15.12.4 Valve schedules providing 'overall' generalinformation for the site shall be suitably framed andglazed and fixed within the main plant room in aposition approved by the PM.

15.12.5 A copy of every valve schedule and circuitcontrol diagram shall be incorporated into each copy ofthe Operation and Maintenance Instruction Manuals.

15.12.6 The valve numbering in the valve schedulesshall correspond precisely with the numbering used onthe valve labels, circuit control diagrams, 'As Installed'drawings and in the Operation and MaintenanceInstruction Manuals.

October 1997 67


Section Sixteen—Water Storage Vessels

16.1 CISTERNS AND COLD WATER TANKS

16.1.1 Cisterns and cold water storage tanks shallcomply with the requirements of DEO Specification036 and the Water Byelaws.

16.2 CHILLED AND CONDENSER WATER BUFFERVESSELS

16.2.1 Buffer vessels shall be cylindrical withdished ends unless otherwise indicated and be of allwelded construction.

16.2.2 Vessel capacity and dimensions shall be asindicated.

16.2.3 Vessels shall be suitable for the systempressure(s) indicated.

16.2.4 Vessels shall be constructed to the shellrequirements of BS 853 and be of an appropriategrade for the operating pressure. Steel plates shall beto BS 1501: Part 3 and appropriate sections of BS EN10028-4: 1995 and BS EN 10029: 1991. Where thepressure and capacity limits are acceptable, vesselsmay be constructed as vertical cylinders to BS 417:Part 2 and shall be mild steel galvanised aftermanufacture.

16.2.5 Instruments, gauges, fittings and connectionsshall be as indicated. Every vessel shall have:

a) a manway or handhole with access cover,

b) wash-out connection,

c) open vent or safety valve,

d) thermometer well.

16.2.6 Connections shall extend clear of the vesselshell surface to accommodate thermal insulation andcladding requirements.

16.2.7 Vessels shall be protectively paintedinternally and externally before the application ofthermal insulation.

16.2.8 Thermal insulation shall comply withSection Seventeen—Thermal Insulation—of thisSpecification. The necessary support cleats shall beprovided on the vessel shell. The extent of insulationshall be as indicated.

16.2.9 Vessels shall be complete with supportcradles or feet and have steel lifting eyes welded on.Suitable precautions shall be taken to avoid theformation of condensation on the lifting eyes andsupport cradles or feet. Unless otherwise indicated,support piers or plinths will be provided by others.

16.2.10 Vessels shall be painted and labelled asagreed with the PM.

16.2.11 Surfaces to be painted shall be cleaned of allmill scale and loose rust and prepared to a finish ofsecond quality to the appropriate part of BS 7079.

16.2.12 Vessels shall be tested in accordance withthe requirements of the construction standard used orto a minimum of 1.5 times the maximum operatingpressure.

16.2.13 The paint scheme for exposed metal surfacesshall be:

micrometre

68 October 1997

Specification 037Air conditioning, air cooling andmechanical ventilation (or buildings

Section Seventeen—Thermal Insulation

17.1 GENERAL

17.1.1 Thermal insulation and methods ofapplication shall comply with the requirements of BS5422 and BS 5970.

17.1.2 The requirements of DEO Specification 036shall apply to thermal insulation used with thefollowing services, equipment and plant:

a) low, medium and high temperature hot water,

b) steam and condensate,

c) domestic hot and cold water.

Thermal insulation to air handling units shall be asdescribed in Section Seven—Air Handling Units—ofthis Specification.

17.1.3 Thermal insulating materials shall complywith BS 3927, BS 3958: Parts 1 to 5 inclusive or BS5608 as appropriate for the particular materialsspecified. Insulating materials that contain and/orrequire the use of CFCs in their manufacture, shallnot be used.

17.1.4 Insulating materials, adhesives, sealantsand finishes, shall be suitable in all respects forcontinuous use without degradation throughout therange of operating temperatures and within theenvironment indicated. They shall be designed toprovide proof against rotting, mould, fungal growthand attack by vermin.

17.1.5 Unless otherwise indicated (or as exceptedby Clause 17.1.6), thermal insulating materials usedwithin any building shall, when tested in accordancewith BS 476: Part 4, be classified non-combustible.Insulation facing materials shall be inherently non-combustible. Thermal insulating materials used withinany building shall be free from substances which, inthe event of fire would generate appreciable quantitiesof smoke or noxious or toxic fumes. Where requestedby the PM, evidence of fire classification, obtainedfrom a NAMAS accredited testing laboratory, shall be

provided by the Contractor in order to certify thatmaterials used comply with this Clause. Nopolystyrene material shall be used for thermal oracoustic insulation purposes within buildings.

17.1.6 Within the building structure, insulatingmaterials and their finishes whose surfaceclassification complies with Class 0, as defined in theBuilding Regulations, may be used.

17.1.7 Insulating materials and finishes shall befree from asbestos. At all positions where insulation tobe installed abuts or involves removal of existingasbestos-containing insulation or finishes, theContractor shall comply with the contents of clauses5.11.7 and 5.12 (Section 2) and Clause 30 (Section 6)of BS 5970. Unless otherwise indicated proceduresshall be agreed with the PM. The Contractor shallnotify and comply with the requirements of the Healthand Safety Executive.

17.1.8 Thermal insulation shall be applied to allsupply and return air ductwork and all plantcomponents which convey heated or cooled air withinplant rooms, unconditioned spaces or the open air.Unless otherwise indicated, thermal insulation shallbe applied to the following:

a) fresh air ductwork in plant rooms and heatedspaces,

b) exhaust air ductwork in unheated spaces andthe open air.

Systems conveying heated or cooled air throughconditioned spaces, as well as above false ceilings andbelow floors that are used as the return air path andincorporate supply air ducts, shall be insulated whereindicated.

17.1.9 Thermal insulation shall be applied to allchilled water pipework distribution systems and to allcomponents within distribution systems. Condenser

October 1997 69



water pipework, cold water pipework, feed andexpansion pipework, and cold water vessels shall beinsulated as indicated.

17.1.10 The minimum thickness of insulation for airand chilled water distribution services shall be to BS5422, Tables 17A, 17B, 17C and 17D in thisSpecification. Where the indicated thickness in thesetables is not a commercial size, the nearest largercommercially available thickness of insulation shall beprovided. The thickness of thermal insulation to waterstorage vessels shall be as specified for flat surfaces inTables 17C and 17D.

17.1.11 Insulation shall not be applied to anyelement of a pipework system until hydraulic testshave been completed and surfaces prepared, all to thesatisfaction of the PM. Ductwork systems shall betested for air leakage as specified, prior to theapplication of thermal insulating materials.

17.1.12 Properties of fibrous insulation materialsshall be as follows:

* (Maximum Thermal Conductivity at a mean temperatureof 50°C).

Rigid material shall be used where sheet metal orpolymeric mastic finish is specified.

17.1.13 Phenolic foam CFC-freepre-formedinsulation, shall be free of water-soluble chlorides, andshall comply with BS 3927.

Properties shall be:

Bulk Density (minimum) 35kg/m3

17.1.14 Segmented type mattress ('lamella') shall befaced with aluminium foil or glass reinforcedaluminium foil/kraft paper laminate.


Bulk Density (minimum) 45kg/m3

Thermal Conductivity (maximum)0.054 W/m K (100°C mean temperature).

17.1.15 Flexible closed-cell insulating material shallbe elastomeric expanded nitrile rubber and shallachieve Class 0 rating (the Building Regulations). Theouter surface shall be of smooth finish. The inherentvapour barrier shall be maintained at all joints.


Bulk Density (nominal) 50-120kg/m3


17.1.16 Fabric facing to insulating materials shall beglass cloth only.

17.1.17 Polyisobutylene sheet shall have a tensilestrength not less than 3.4MN/m'. Sheet shall be0.8mm minimum thickness.

17.1.18 Metal cladding shall be in accordance withTable 5 of BS 5970.

17.1.19 Where ceiling void spaces/roof spaces areused as a direct path for either return air or supplyair distribution, the ceiling and all pipework, ductworkand units installed within these spaces shall not beinsulated with fibrous material.

17.2 DUCTWORK AND AIR HANDLING PLANT-INSULATION MATERIALS AND FINISHES

17.2.1 Within buildings, where concealed from viewand not readily accessible, the following shall beprovided as indicated:

a) Pre-formed slab material or flexible roll with afacing of factory-applied glass fibre reinforcedaluminium foil or plastics film; secured byadhesive and piercing fasteners or enclosedwithin galvanised wire netting to BS 1485,25mm mesh, 1mm thick. All joints andexposed edges shall be sealed with tape, of thesame material as the insulation facing, andheld in place with site-applied adhesive.


70 October 1997



b) Pre-formed slab material, secured by adhesiveand piercing fasteners, enclosed in glass fibrereinforced aluminium foil with all laps sealed.

c) Pre-formed slab material, secured by adhesiveand piercing fasteners, enclosed inpolyisobutylene sheet fixed with adhesive tothe insulating material and bonded to itself atall laps.

d) Pre-formed slab material, secured by adhesiveand piercing fasteners, covered or enclosed inglass cloth fixed with adhesive to theinsulating material and finished with twocoats of appropriate vapour sealing compound.

17.2.2 Within buildings, where exposed to view butnot readily accessible, the following shall be providedas indicated:

a) As Clause 17.2.1 (b).

b) As Clause 17.2.1 (c).

c) As Clause 17.2.1 (d) and painted to matchdecoration of surroundings.

17.2.3 Insulation applied in plant rooms shall beprotected to prevent mechanical damage. Whereindicated, insulation applied in other areas shall beprotected to prevent mechanical damage. Mechanicalprotection shall be provided by enclosing insulationwithin 1.0mm thick aluminium sheet or 0.8mm thickgalvanised mild steel sheet.

17.2.4 Air handling plant, ductwork and associatedequipment located outside buildings, shall be insulatedwith closed-cell material of Class 0 rating with smoothexternal surface. Joint shall be caulked with approvedsealant and the insulation painted overall withexternal grade paint as appropriate. The followingfinish shall be provided as indicated:

a) Polyisobutylene sheet fixed with adhesive tothe insulating material and bonded to itself atall laps.

b) Roofing felt and galvanised wire netting to BS1485, 25mm mesh, 1mm thick.

c) Polymeric emulsion coating.

d) Fully enclosing cladding of 1.0mm thickaluminium sheet or 0.8mm thick galvanisedmild steel sheet, with all joints overlapped,mastic sealed and arranged to shed water.

17.3 DUCTWORK AND AIR HANDLING PLANT-METHODS OF APPLICATION

17.3.1 Fixing methods for insulation shall providea minimum of direct metal paths which thermallybridge the insulation, particularly when the insulationis metal faced. The full insulating effect shall bemaintained at connections and access openings andpanels including the edges of such openings. Thermalinsulation shall cover all forms of flanged joints,fasteners and stiffeners either by means of purpose-made boxes or by increasing the general thickness ofthe insulation to give at least 6mm cover. Wheremultiple-layer insulation is applied, the joints in eachlayer shall be staggered.

17.3.2 At all points of support, the insulation, outercovering and, where applicable, vapour seal, shall becontinuous and shall not be pierced or fouled by thesupports. The insulation at supports shall be materialof sufficient compressive strength to carry the loadstransmitted to the supports. The load-bearinginsulation shall be extended on each side of suchlocations.

17.3.3 Insulation, including faced material, shall beapplied and arranged such that top and bottom slabsoverlap the side slabs to maintain a uniform thicknessat corners. The insulation shall be fixed securely withadhesive supplemented by piercing fasteners whichmay be rustproof metal studs, split prongs, plasticstuds or other approved devices fixed to the ductsurfaces. Fastenings shall be suitable for the thicknessand weight of the insulating materials and finishes tobe applied. Fastenings shall be spaced atapproximately 300mm centres, and shall finish flushwith or below the surface of the insulation. Adhesivesshall be non-flammable and compatible with theinsulation. In no circumstance shall adhesive be usedwhich attacks or dissolves the ductwork, insulation orvapour seal.

17.3.4 Where thermal insulation is protectedagainst the effects of weather by flexible sheetmaterial, particular care shall be taken to ensure awatertight seal at all joints. The sheet material shallbe adhered to the external surface of the insulationand all joints shall be lapped, secured and sealed byadhesive or solvent welding. All such jointing andsealing materials, and methods of application, shall beto the recommendations of the sheet manufacturer.

17.3.5 Flexible roll or segmented mattressinsulation shall be fixed to 150mm widecircumferential bands of suitable adhesive firstapplied to the metal surfaces at 300mm centres.

October 1997 71



Circumferential and longitudinal joints shall be sealedwith tape, of the same material as the insulationfacing, and held in place with site-applied adhesive.The external surface of the insulation shall bewrapped with galvanised wire netting to BS 1485,25mm mesh, 1mm thick, and the netting joints shallbe secured with a lacing of 1mm galvanised wire. Careshall be taken to ensure that the insulating materialis not compressed during application.

17.3.6 For fixing of thermal and acoustic liningssee Section Twenty-One—Vibration Isolation andNoise Insulation—of this Specification.

17.3.7 Airtight sleeves to bridge insulation atperforations shall be in accordance with SectionSeven—Air Handling Units—of this Specification.

17.4 CHILLED WATER PIPEWORK AND EQUIPMENT-INSULATION MATERIALS AND FINISHES

17.4.1 Pipework shall be insulated with pre-formedsplit sections as indicated:

a) Flexible closed-cell elastomeric tubularinsulation.

b) Rigid closed-cell foamed moulded sectionswith bonded aluminium foil facing.

c) Rigid closed-cell foamed moulded sectionssuitable for direct application of a polymericemulsion vapour seal.

d) Bonded mineral fibre covered with glass fibrereinforced aluminium foil/ kraft paperlaminate.

Insulation to equipment shall be of the same materialas insulation for pipework.

17.4.2 Within buildings, where concealed fromview, the following shall be provided as appropriate tothe location:

a) In roof spaces: Glass fibre reinforcedaluminium foil with laps factory-applied topre-formed sections. Laps pasted down andleft unpainted.

b) In permanently concealed situations, (eg. builtinto ducts, voids, chases, etc), without access:Glass cloth or glass fibre reinforcedaluminium foil with laps factory-applied topre-formed sections. Laps pasted down andleft unpainted. Glass cloth to be vapoursealed.

c) In all accessible ducts, voids, chases, etc:Glass cloth with two coats of polymericemulsion applied 'in situ' to pre-formedsections. Left unpainted.

17.4.3 Within buildings, where exposed to view butnot readily accessible, the following shall be providedas indicated:

a) Glass fibre reinforced aluminium foil withlaps factory-applied to pre-formed sections.Laps pasted down and left unpainted.

b) Pliable plastics, elastomer sheets or rigidplastics, all not less than 0.35mm thick.Either factory-applied to pre-formed sectionsand lapped and sealed with adhesive, orsupplied loose and wrapped to pre-formedsections on site with lapped and sealed joints.The sheets shall be either self-coloured asagreed with the PM, or finally painted.

c) Aluminium foil faced pre-formed sections withlaps pasted down and finally sealed by theapplication of 75mm wide glass fibrereinforced aluminium foil faced tape with site-applied adhesive over all longitudinal andcircumferential joints.

17.4.4 Insulation applied in plant rooms shall beprotected to prevent mechanical damage. Whereindicated, insulation applied in other areas shall beprotected to prevent mechanical damage. Mechanicalprotection shall be provided by enclosing insulationwithin fabricated sheet aluminium casings inaccordance with Table 5 of BS 5970.

17.4.5 Chilled water pipework and associatedequipment located outside buildings, shall be insulatedwith closed-cell material of Class 0 rating in pre-formed sections or sheets. Pre-formed sections orsheets shall have a smooth external surfaceincorporating a vapour barrier. The following finishshall be provided as indicated:

a) Fully enclosing cladding of 1.0mm thickaluminium sheet or 0.8mm thick galvanisedmild steel sheet, with all joints overlapped,mastic sealed and arranged to shed water.

b) Two applications of fully compatibleelastomeric weatherproof coating to provideadditional protection against airbornechemical attack, improve ozone resistance andprevent ageing.

72 October 1997



c) Polyisobutylene sheet fixed with adhesive tothe insulating material and bonded to itself atall laps.

17.4.6 Rectangular water storage vessels shall bethermally insulated with pre-formed rigid foam slabsfaced on the outer side with aluminium foil.Alternatively, or where indicated, flexible closed-cellinsulating material of Class 0 rating in sheet form andincorporating a vapour barrier shall be used.

17.4.7 Horizontal and vertical cylindrical waterstorage vessels up to 1.2m diameter shall be insulatedby using rigid foam, faced on the outer side withflame-retardant scrim cloth or aluminium foil, or byusing radiussed lags of resin-bonded glass fibre.

17.4.8 Horizontal and vertical cylindrical waterstorage vessels exceeding 1.2m diameter shall beinsulated by using shaped rigid foam slabs set in anapproved adhesive.

17.5 CHILLED WATER PIPEWORK AND EQUIPMENT-METHODS OF APPLICATION

17.5.1 Insulation shall fit closely to the pipeworkand other surfaces without gaps between joints. Eachsection of pre-formed insulation shall be secured to thepipe by means of circumferential bands of non-corrodible metal, plastics, fabric, or glass fibrereinforced tape set in site-applied adhesive. Flexibleclosed-cell insulation shall be sleeve mounted onpiping or shall be split, snap fitted and all jointssecured with adhesive recommended by the insulationmanufacturer.

17.5.2 Insulation shall be secured to water storagevessels and flat surfaces by setting in an approvedadhesive. Additionally, materials shall be securelypegged and wired. Joints between rigid blocks shall bepointed with flexible flame-retardant mastic.

17.5.3 Radiussed and bevelled lags shall be set inan approved adhesive, carefully butted together andsecured by metal tensioning bands at no greater than450mm centres. The joints shall be sealed with100mm wide glass fibre reinforced tape bedded in anapproved site-applied adhesive.

17.5.4 Insulation support rings, cleats or othersupport fixings shall be provided as necessary to waterstorage vessels.

17.5.5 Tube chests and the like shall be coveredwith removable lined boxed sections with similar loosematerial to fill voids. Support legs or skirts shall beinsulated for a length of four times the insulationthickness down from the insulated body surface.

17.5.6 Valves, flanges and other fittings shall beprovided with removable pre-formed insulated boxeswith facings as indicated. Two vapour barriers shall beprovided, one to totally enclose the main insulationand the other to cover the removable insulation.

17.5.7 The requirement for loose covers, access tomanways, mudholes and the like shall be met bytrimming, and the provision of any necessary supportsof the insulation covering to suit.

17.5.8 At all points of support, the insulation, outercovering and vapour seal, shall be continuous andshall not be pierced or fouled by the supports. Theinsulation at supports shall be material of sufficientcompressive strength to carry the loads transmitted tothe supports. The load-bearing insulation shall beextended on each side of such locations.

17.5.9 Service entries into buildings shall be madeweatherproof to the satisfaction of the PM.

17.6 VAPOUR BARRIERS

17.6.1 Thermal insulation applied to the outside ofpiped and ducted services, equipment and plant usedto convey, store or generate fluids or gases at sub-ambient temperatures, shall be provided with avapour barrier. The vapour barrier shall be appliedsuch that it is continuous and gives protection to thewhole surface of the insulation which it covers. Thevapour barrier shall not be pierced or otherwisedamaged. Means of load distribution shall be providedat points of support as necessary. The followingpermeance values for vapour barriers shall not beexceeded:

Chilled water pipework and equipment 0.015g/(s MN)Refrigeration work (cold surface 0°C) 0.010g/(s MN)Other applications 0.050g/(s MN)

17.6.2 The material chosen for the vapour barrierand its method of application shall be compatible withthe thermal insulation which it is to protect. Thefollowing may be used (subject to Clauses 17.1.5 and17.6.1):

a) Wet-applied vapour barriers of the cut-backbitumen type, bitumen emulsions with orwithout elastomeric latex, vinyl emulsions andsolvent based polymers.

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b) Elastomer sheets with all joints adequatelyoverlapped and continuously vapour sealed.

c) Polyvinyl chloride, polyethylene,polyisobutylene or other suitable plasticstapes or sheets.

d) Epoxy and polyester resins.

e) Glass fibre scrim reinforced metal foil usedalone or laminated to building paper, buildingsheet or plastics film with all jointsadequately overlapped and continuouslyvapour sealed.

17.7 PAINTING AND IDENTIFICATION

17.7.1 Thermal insulation exposed to view,(including that within plant rooms), shall be paintedexcept where protected by metallic foil or sheet, plasticfilm or a weatherproof finish. An undercoat and notless than two finishing coats shall be applied.Absorbent surfaces shall, in addition, receive an initialcoat of priming paint. All paints shall be compatiblewith the surfaces to which they are applied.

17.7.2 The colour(s) of paint(s) shall be to theinstructions of the PM and will be selected from therange contained in BS 381C unless otherwise indicated.

17.7.3 All piped distribution services shall becolour coded in accordance with BS 1710 and providedwith symbols for identification purposes. Identificationcoding for ductwork, including thermal insulation,shall be in accordance with the recommendations inAppendix C of HVCA Specification DW/142.

17.7.4 All pipework shall be identified by colourbands at least 25mm wide. All ductwork shall beidentified by colour triangles with a side length of atleast 150mm. The bands or triangles shall be spacedand located to permit ready identification of theservices, particularly adjacent to equipment positions,at all valves, at service junctions, at wall penetrationsand at all changes of direction.

17.7.5 In addition to the colour bands and trianglesrequired in Clause 17.7.4, all pipework and ductworkin plant rooms and service areas, shall be indeliblyand legibly marked with black or white letters andarrows, to show the type of service and the direction offluid flow. Lettering shall be 50mm in height or ofpipe nominal bore where this is smaller. All waterstorage vessels shall be properly labelled inaccordance with the requirements of the PM. Servicesshall be shown as follows:

Chilled water CHWCooling water CLWSupply air SAReturn or recirculated air RAFresh air FAExhaust air EA

The letters F and R shall be added to pumpeddistribution to show flow and return respectively. Allsymbols shall conform to the legend on the 'AsInstalled' drawings and plant room valve charts.

74 October 1997



TABLE 17A ECONOMIC THICKNESS OF INSULATION ON DUCTWORK CARRYING WARM AIR

TABLE 17B MINIMUM THICKNESS FOR INSULATION FOR CONDENSATION CONTROL ON DUCTWORK CARRYING CHILLED AIR

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TABLE 17C MINIMUM THICKNESS OF INSULATION FOR CHILLED AND COLD WATER SUPPLIES TO PREVENT CONDENSATION

ON A HIGH EMISSIVITY OUTER SURFACE (0.9) WITH AN AMBIENT TEMPERATURE OF + 25°C AND A RELATIVEHUMIDITY OF 80% R.H.

TABLE 17D MINIMUM THICKNESS OF INSULATION FOR CHILLED AND COLD WATER SUPPLIES TO PREVENT CONDENSATION

ON A LOW EMISSIVITY OUTER SURFACE (0.2) WITH AN AMBIENT TEMPERATURE OF + 25°C AND A RELATIVEHUMIDITY OF 80 % R.H.

76 October 1997


Section Eighteen—Water Treatment

18.1 GENERAL

18.1.1 Pretreatment plant and chemicalconditioning equipment for the water systems shall beprovided as indicated, to meet the specifiedcharacteristics for initial-fill water, make-up waterand system circulating water. The equipment shallcomprise purpose-made sets manufactured byapproved firms and shall include all necessarycomponents and sundries.

18.1.2 Water treatment plant and equipment shallbe arranged in neat and compact layouts allowingproper access for maintenance and for simpleoperation without spillages.

18.1.3 Details of the source and character of thewater supplied to the plant rooms, the water pressureat the points of supply, the specifications of therequisite water treatment processes and throughputrates, and the chemicals to be used shall be asindicated.

18.1.4 Proposals for water treatment plant,equipment selection and detailed design shall beapproved by the PM before orders are placed.

18.1.5 The initial fill of water, pretreated andchemically conditioned to the specified requirements,shall be made immediately after the water systemshave been cleaned and flushed out. The watertreatment plant and equipment must be installed andcommissioned in order to carry out this initial fill. Ifthe plant and equipment is unable to meet thisrequirement, water of the specified characteristics andin sufficient quantity to totally fill the systems, plantand equipment, must be provided by the Contractor byother means and at no extra cost.

18.1.6 Once the water systems have been filledwith treated water, the Contractor will be responsiblefor operating and maintaining the water treatmentplant and equipment and for checking andmaintaining the specified characteristics of the make-up water and water within the systems until the time

of handover of the installation. Systems which havebeen drained must be properly cleaned and disinfectedbefore being put back into use.

18.1.7 Component parts of the pretreatment plantand chemical conditioning equipment shall beconstructed from durable materials and, if necessary,shall be suitably treated with a corrosion-resistantcoating on surfaces that are liable to exposure to thechemical solutions used.

18.2 PRETREATMENT PLANT

18.2.1 Base exchange water softening plant shallmeet with the recommendations of BEWA Code ofPractice 01.85.

18.2.2 Water pretreatment plant that is directlyconnected to the water supply shall be provided withcheck and anti-vacuum valves complying with BS6282 and/or other means of protection from back-flowas may be required by the Water Company.

18.2.3 Pretreatment plant shall be provided withby-pass arrangements to permit the use of temporaryplant either for initial filling or for service in the eventof failure.

18.2.4 Effluent from water treatment plant andequipment shall have provisions for treatment asindicated before discharge into the drainage system.

18.2.5 A cumulative water meter, calibrated inlitres and with a pulsed output, shall be provided onthe water supply connection to each make-up watersystem. The metering system shall include delayed-action float valves or automatic valves as necessary, toensure meter accuracy.

18.2.6 Unless otherwise indicated, pretreatmentplant requiring regeneration shall not regeneratemore frequently than once daily at the maximumthroughput rate. Sufficient storage capacity shall beprovided for make-up purposes during regenerationperiods.

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Section Eighteen—Water Treatment

18.3 WATER SAMPLING AND TEST EQUIPMENT

18.3.1 Provision for taking water test samples fromchilled water and cooling water systems shall beprovided at the locations indicated.

18.3.2 Water test sample containers approved bythe PM shall be provided as indicated.

18.3.3 Water treatment test kits shall be providedas indicated.

18.3.4 On-site staff shall be instructed in correcttest procedures, monitoring and adjustment of dosing.

18.4 CHEMICAL DOSING AND BLEED-OFF

18.4.1 Chilled water systems shall be provided withdosing pots to enable shot dosing of chemical solutions.

18.4.2 Cooling water systems shall be providedwith chemical solution injection systems.

18.4.3 Bleed-off equipment shall be provided forautomatic control of the water conductivity in coolingwater systems.

18.5 CORROSION MONITORING EQUIPMENT

18.5.1 In each water system where watertreatment is specified, a corrosion monitoring rig shallbe installed as indicated.

18.6 STORAGE OF CHEMICALS

18.6.1 Stores of chemicals required to operatewater pretreatment plant and equipment, and tocondition the initial-fill water, make-up water andsystem circulating water, shall be supplied anddeposited at locations to be agreed with the PM.Unless otherwise indicated, sufficient quantities ofchemicals shall be supplied to permit the initial fillingand any subsequent refilling in accordance with thisSpecification, commissioning and operation at designconsumption rates, and for 2 months after handover ofthe plant.

18.6.2 Separate transfer pumps, pipework and/orhoses must be installed for incompatible chemicalswhich are pumped from storage areas to watertreatment plant and equipment.

78 October 1997


Section Nineteen—Heat Wheels, Heat Pipes, Airand Water Plate Heat Exchangers and Run-aroundCoils

19.1 GENERAL

19.1.1 Heat recovery/heat exchange units shallhave the efficiencies indicated.

19.2 HEAT WHEELS

19.2.1 Rotating regenerative air-to-air heatrecovery units shall transfer sensible or total heat asindicated between the exhaust and intake airstreams.

19.2.2 Heat wheels shall consist of a rigid mild steelcasing protected against corrosion, containing asectorised wheel composed of aluminium foil or otherapproved heat exchange media, treated with a coatinghaving the necessary hygroscopic properties where totalheat extraction is specified. The coating or the heatexchange media shall not support bacteria, fungi ormould growth.

19.2.3 A central division plate shall separate theintake and exhaust airstreams. An adjustable sealingstrip shall be included to minimise air leakage fromthe exhaust airstream to the intake airstream.

19.2.4 Heat wheels shall be complete with apurging sector with carry-over certified to be amaximum of 0.05% of the intake air volume withdirectionally orientated media.

19.2.5 The motor shall be complete with mountingbracket, gearbox and drive system, with necessarydrive guards, and shall be suitable for single speed orvariable speed operation as indicated.

19.2.6 Provision shall be made for adjustment ofdrive belt or drive chain tension.

19.2.7 Heat wheels shall have drilled flanges topermit fixing into a ductwork system. Access doorsshall be located on each side of the heat recovery unitin the adjacent intake and exhaust ductwork.

19.3 HEAT PIPE UNITS

19.3.1used.

Heat pipes that contain CFCs shall not be

19.3.2 Heat pipe units shall comprise a galvanisedmild steel frame and casing, housing a number of heatpipes of seamless copper tube, fitted with flat platefins which shall be of copper unless otherwiseindicated.

19.3.3 A central division plate shall separate theintake and exhaust airstreams.

19.3.4 Heat pipe ends shall be protected by airtightcovers fitting to the main casing and constructed ofthe same material. Frame side panels shall beconstructed to allow free expansion of the heat pipesinto the end covers.

19.3.5 Access doors shall be located on each side ofthe heat pipe unit in the adjacent ductwork.

19.4 PLATE HEAT EXCHANGERS (AIR)

19.4.1 Plate heat exchangers shall be fittedcomplete with framing, stiffened side panels and endflanges to match those of adjacent unit sections.

19.4.2 Each unit shall be composed of heat transferplates of commercially-pure aluminium, or otherapproved material with synthetic rubber sealingjoints, arranged for cross-flow of airstreams.

19.4.3 No mixing shall occur between airstreams.

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Section Nineteen—Heat Wheels, Heat Pipes, Air and Water Plate Heat Exchangers and Run-around Coils

19.4.4 Units shall be suitable for operation in thetemperature and humidity conditions indicated.

19.4.5 Provision shall be made for cleaning theheat exchange surfaces and trapped condensate drainsshall be provided.

19.5 PLATE HEAT EXCHANGERS (WATER)

19.5.1 Plate heat exchangers shall comprisecorrugated plates with primary and secondary fluidports, assembled with ring gaskets and plate seals,mounted on a frame having end-support plates, rackand end posts, and clamped together with long boltsand tube washers acting on loose end pressure plates.

19.5.2 End plates shall carry screwed connectionsfor piping up to 50mm size and flanged connections forpiping 65mm size and above.

19.5.3 Gasket materials shall be entirely suitablefor the fluids to be used and shall be Water ResearchCentre approved.

19.5.4 Plates shall be fabricated in Grade 316stainless steel or other approved material.

19.5.5 The assembly and frame members shall belocated on concrete plinths as indicated.

19.5.6 When used in conjunction with an open-circuit cooling tower, the design fouling factor on thecooling tower side shall not be less than 0.00018m2K/W unless otherwise indicated.

19.5.7 Units shall be preceded by a pipelinestrainer where indicated.

19.6 RUN-AROUND COILS

19.6.1 Construction and arrangement of heatexchange coils for use in run-around systems shall bein accordance with Section Five—Air Heater andCooler Batteries—of this Specification.

80 October 1997


Section Twenty—Belt Variable SpeedDrives and Guards

20.1 BELT DRIVES

20.1.1 Belt drives shall comply with BS 3790 andbe capable of transmitting at least the rated poweroutput of the driving motor at any stage of operationwith one belt removed. Unless otherwise indicated, notless than two belts per drive shall be used and allmultibelt drives shall use matched sets. Belts shall beof rubber and fibre Vee' section unless otherwiseindicated.

20.1.2 Pulleys shall be correctly aligned inaccordance with the manufacturer's requirements andthe Contractor shall ensure that any fixing bolts arecorrectly built in by the Building Contractor.

20.1.3 Provision shall be made to permit drivealignment and adjustment of belt tension. For fanswith shaft power up to 5kW, pivoted mounting platesand jacking bolts may be used. For fans with shaftpower above 5kW, slide rails and jacking bolts shall beprovided. Pumps shall have a resiliently-mountedmotor plate, hinged for adjustment by lockable screwaction.

20.1.4 Where duplicate motors are provided andfixed, the spare motor shall be complete with anadjusting device to allow belt tensioning and shall bein all respects ready for operation. The centre-to-centre dimensions between the common driven pulleyand the duplicate driving pulleys shall be the same.

20.2 VARIABLE SPEED DRIVES

20.2.1 Variable speed drives shall be providedwhere indicated and shall be one of the followingtypes, (as described in Clauses 20.2.2 to 20.2.5), asindicated.

20.2.2 Oil-filled fluid couplings shall be completewith cased impeller and runner, sump, charging pipeand pump, line pressure detector/controller andcontrol pressure section.

20.2.3 Variable speed or variable torque outputunits of the electro-magnetic induction type utilising aconstant speed electric 400/230V, 50Hz a.c. motor witha variable speed output shaft. Output shaft rotationshall be induced by eddy currents generated in thetube assembly fitted over the motor output shaft. Allseparate items shall be fitted in enclosures to BS EN60439 provided by the manufacturer.

20.2.4 Switched reluctance drive motors shall havea salient-pole rotor and stator of rugged compactconstruction. Motors shall have a built-intachogenerator/encoder and shall operate withmicroprocessor control.

20.2.5 Inverter drives shall be pulse widthmodulation or direct torque control type complete withline supply filters and inverter unit mounted insuitable enclosures to BS EN 60439, by-pass unit andall necessary controls. Equipment shall be suitable for400V three-phase 50Hz electrical supply. Enclosuretemperatures shall be limited to 40°C, with forcedventilation where necessary. Enclosure constructionshall provide protection of appropriate IP rating to BSEN 60529. Inverters shall be CE marked to meet EMCrequirements.

20.3 BELT DRIVE PULLEYS

20.3.1 Belt-driven fans and pumps shall be fittedwith pulleys suitable for the belt drive used. Pulleysmay use split taper bushings of an approved type fordrives up to 30kW. Alternatively, and in any caseabove 30kW output, pulleys shall be secured to the fanor motor shafts by keys fitted into machined key ways.Pulleys shall be keyed to the shaft in the overhungposition. Keys shall be easily accessible for withdrawal

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Section Twenty—Belt Drives, Variable Speed Drives and Guards

or tightening and shall not protrude beyond the end ofthe shaft. Keys without gib heads shall be drilled andtapped to accept an extractor bolt.

20.4 GUARDS

20.4.1 Guards shall comply with BS 5304 and beprovided to all open fan intakes and exhausts, allforms of open power transmission systems includingbelt drives, drive shafts and drive couplings, dischargeopenings from cooling towers, and elsewhere whereindicated.

20.4.2 Fixed guards shall be installed to preventinadvertent contact with dangerous parts ofmachinery. Construction and installation shall ensurestrength and rigidity. It shall not be possible to removeany guard or access panel without the aid of a tool.

20.4.3 Fan guards shall be purpose-made by thefan manufacturer or meet with the fan manufacturer'sapproval, and be constructed from galvanised orplastic coated steel wire.

20.4.4 Belt drive guards shall be of galvanisedwoven steel wire of not less than 2.5mm diameterattached to a rigid galvanised steel rod or angle

framework. The mesh size and/or the location of theguard shall prevent finger contact with any encloseddanger point. Alternative construction may be fromgalvanised sheet steel not less than 0.8mm thickstiffened as necessary to ensure a rigid enclosure.Removable access panels shall be provided to permittachometer readings to be made of motor and drivenshafts and belt tension to be tested. The sizes ofguards, including the dimensions and locations ofaccess panels, shall provide for the extreme motorposition.

20.4.5 For duplicate motor installations, the guardprovided shall be arranged to protect both drives. Allfixings and mountings shall be installed to facilitatechange-over of the drive.

20.4.6 Shafts and couplings shall be protected witha galvanised steel wire mesh or sheet metal guardshaped to suit the components and removable formaintenance.

20.5 ELECTRIC MOTORS

20.5.1 Electric motors shall comply with SectionTwenty-Five—Electrical Equipment and Wiring of thisSpecification.

82 October 1997


Section Twenty-one—Vibration Isolation and NoiseInsulation

21.1 ANTI-VIBRATION PROVISIONS

21.1.1 All dynamic machinery shall be isolatedfrom the building structure by vibration isolators and/or vibration isolation materials which shall bepurpose-designed and selected to suit the machinery.Where mat type isolation materials are used, theContractor shall supply the materials and shall beresponsible for their correct positions and installation.All other vibration isolators shall be both supplied andinstalled by the Contractor. Isolation efficiency of anti-vibration devices and materials shall be as indicated.

21.1.2 For fans and air distribution systems,flexible joints in accordance with Section Eight—Ductwork, Dampers and Terminal Devices of thisSpecification shall be provided. For pumps and waterdistribution systems, purpose-designed flexibleconnections shall be provided in accordance withSection Fourteen—Pipework of this Specification. Theconnections shall be compatible with the tubematerials, the methods of jointing and the fluid(s)handled in the system.

21.1.3 Electrical connections to motors and otherdynamic machinery, shall be made in accordance withDEO Specification 034.

21.2 NOISE

21.2.1 Plant and equipment shall be selected andinstalled to ensure that the noise level in the spacesserved, in any adjacent buildings and within plantroms does not exceed the indicated maximumacceptable noise rating (NR). Sound power levelinformation for plant and equipment shall be stated inSchedule No. 2. Sound pressure level data is notacceptable.

21.3 NOISE INSULATION (AIRBORNE NOISE)

21.3.1 Attenuators and other noise controlequipment shall be selected and installed to achievethe stated noise ratings with minimum resistance toair flow. Fire properties of sound absorbent materialsshall be in accordance with Section Seventeen—Thermal Insulation—of this Specification. Soundabsorbent materials that contain and/or require theuse of CFCs in their manufacture, shall not be used

21.3.2 Factory fabricated attenuators shall betested in accordance with BS 4718. The dynamicinsertion loss and generated noise level for eachoctave band, and the pressure loss of each attenuatorshall be stated in Schedule No. 2.

21.4 CIRCULAR AND RECTANGULAR ATTENUATORS

21.4.1 Casings shall be of not less than 0.8mmthickness galvanised mild steel sheet. Joints andseams shall be designed and constructed to minimiseair leakage by use of mastic or other suitable sealingmethod. End flanges shall be welded to the casingswith fixing details and construction methods inaccordance with HVCA Specification DW/142. Weldingareas shall be cleaned and coated with zinc-rich paint.

21.4.2 Acoustic material must not break up, erodeor migrate at up to and including 150% of full duty airflow or at up to and including 100% relative humidity.An impervious envelope shall be fitted over thefollowing acoustic fill:

a) Mineral fibre insulation.

b) Open-cell acoustic/thermal foam insulationthat is not supplied complete with an inherentPVC sprayed vapour barrier or flexiblepolyurethane film.

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Section Twenty-one—Vibration Isolation and Noise Insulation

Inspection covers be in accordance with SectionEight—Ductwork, Dampers and Terminal Devices—ofthis Specification, shall be provided at both ends ofattenuators.

21.4.3 The dynamic insertion loss of attenuatorsshall include the effect of any facing materials.

21.4.4 Vapour barriers which are not an inherentpart of the acoustic material, shall be of minimumthickness not exceeding 0.07mm and shall be installedunstressed. The material shall be inherently non-combustible and limit the surface spread of flame toClass 1 when tested in accordance with BS 476: Part 7and shall not emit toxic or hazardous fumes if ignited.Membranes used shall be suitably supported andfixed. Any loss of acoustic performance due to thistreatment will be deemed to be accommodated in theoverall performance of the noise control equipmentselected by the Contractor.

21.4.5 Splitter elements in straight rectangularattenuators shall stand vertically, and shall be a tight-fit within the casing. L-section and T-section splitterattenuators shall be designed for smooth air flow.Splitters in bend attenuators shall be fittedperpendicular to the plane of the bend. Where splitterelements are horizontal, eg in ceiling spaces, adequatesupport and retention of acoustic infill must beprovided.

21.4.6 The direction of air flow through eachattenuator shall be clearly marked on the outer casing.

21.5 SOUND ABSORBENT DUCTWORK LININGS

21.5.1 Sound absorbent linings shall not be usedinside ductwork unless indicated as being required.

21.5.2 Linings shall not reduce the required airwaydimensions.

21.5.3 Acoustic materials and associated vapourbarriers for linings shall be in accordance withClauses 21.4.2 to 21.4.4. Inspection covers, inaccordance with Section Eight—Ductwork, Dampersand Terminal Devices—of this Specification, shall beprovided at both ends of ductwork sections containingsound absorbent linings.

21.5.4 No combustible lining shall be installedwithin 1m of any fire damper (BS 5970).

21.6 FIXING OF THERMAL AND ACOUSTIC LININGS

21.6.1 Insulation materials shall accurately fit theinternal surfaces of the duct. The insulation shall befixed using adhesive spread over the entire surface,supplemented by piercing fasteners as necessary,finished flush with the insulation surface. Particularcare shall be taken to ensure that the edges of allinternal insulating materials, whether exposed orbutted against similar edges, are sealed and securedto the internal surfaces of the duct.

In addition to adhesive and piercing fasteners,thermal and/or acoustic insulation shall be retained inposition as follows:

a) Foam insulation shall be secured to the ductwith angle brackets or straps at corners andelsewhere as required.

b) Mineral fibre insulation shall be containedbehind securely fixed perforated metalenclosures.

21.6.2 Airtight sleeves to bridge insulation atperforations shall be provided in accordance withSection Seven—Air Handling Units of thisSpecification.

21.7 ACOUSTIC ENCLOSURES

21.7.1 Where indicated, an acoustic enclosure shallbe provided to isolate the noise-producing equipmentfrom the room in which it is installed. The requirednoise reduction or the maximum permitted ambientnoise rating (NR), shall be as indicated. Removablepanels shall give access to items requiring cleaning,adjustment, replacement and other maintenance.Where enclosures are designed for personnel access,internal lighting and viewing panels shall be provided.Access doors shall be openable from both sides.

21.7.2 The enclosure shall be isolated from thenoise-producing equipment. The enclosure shall alsobe isolated from the building structure.

21.7.3 Provisions shall be made to dissipate heatemitted from the noise-producing equipment wherenecessary.

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Section Twenty-two—Instruments

22.1 GENERAL

22.1.1 Instrumentation relating to heatinginstallations shall be provided in accordance withDEO Specification 036.

22.1.2 The instruments, gauges and devicesdetailed in this section shall be provided in addition tothose associated with specific items of plant. Allinstruments, gauges and devices which haveindicating scales shall be so mounted to be accessibleand easily read from floor level or from platformswithout the need for additional means of access.

22.1.3 Instruments directly associated with itemsof equipment are located within this Specification asfollows:

Section TwoSection FourSection EightSection Fourteen

Section FifteenSection Twenty-Two

Refrigeration gaugesManometersTest holes in ductworkOrifice platesVenturi metersThermometer pocketsCommissioning setsMultipoint temperatureindicators

22.1.4 Scale ranges shall be appropriate to theplant when running and when at rest. The designmaximum operating condition shall be indicated atapproximately 75% of full scale. Unless otherwiseindicated, gauges and dial thermometers shall be tothe accuracy required by BS 1780 and BS 5235respectively. Thermometers shall be graduated indegrees Celsius. Hydraulic and compressed airpressure gauges shall be graduated in bar.Instruments indicating duct air pressure shall begraduated in pascals.

22.1.5 Instruments shall not be subject to vibrationin their installed position.

22.1.6 Where instruments cannot be mounted in aneasily read position, remote reading types shall beprovided with indicators clearly identified and groupedin a position agreed with the PM.

22.2 AIR SYSTEM PRESSURE GAUGES

22.2.1 Pressure gauges shall be provided for all fansystems where the fan power exceeds 3.75kW. Twogauges, each of the single-limb inclined manometertype, shall be provided for each fan and these shall bearranged to indicate the system static pressure on thesuction and discharge sides.

22.2.2 Pressure gauges shall be connected into thesystem at points agreed with the PM. On completionof commissioning, the suction and discharge staticpressures indicated by the gauges shall be indeliblymarked adjacent to them.

22.3 AIR SYSTEM THERMOMETERS

22.3.1 One 13mm diameter test hole shall beprovided for the insertion of a thermometer in each ofthe following locations:

a) the fresh air connection,

b) the recirculation air duct(s),

c) the supply air duct(s),

d) before and after each air heater,

e) before and after each air cooler,

f) before and after each humidifying device.

At each point where the system air moisture contentmay vary, a second test hole shall be providedadjacent to those listed above to enable coincident wet-bulb and dry-bulb temperatures to be measuredsimultaneously. Sealing plugs shall be provided for alltest holes.

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22.3.2 Two thermometers of each type and of eachrange necessary, shall be provided individually packedin protective casings, labelled to facilitate correct use,and handed to the PM by the Contractor.Thermometers shall be of the solid stem generalpurpose type to BS 1704 at least 300mm long, with anaccuracy of ±0.5°C. Each thermometer shall becomplete with a pierced plug to fit the test hole andeach wet-bulb thermometer shall be provided with afabric sleeve. Where test holes cannot be positioned sothat thermometers are unaffected by thermalradiation due to heaters or coolers, shieldedthermometers shall be provided, the test holes beingsized to accept the shielded instruments.

22.3.3 Where the system supply air volume flowrate is 5m3/s or more, a duct-mounted thermometershall be provided and installed at each location listedin Clause 22.3.1. Thermometers shall be of the vapourpressure type having dials not less than 100mmdiameter with white face and black scale graduationsand numbering, with approved metal or mouldedplastics cases.

22.3.4 Remote reading thermometers shall be ofthe electrically energised or vapour pressure typeproviding single or multi-point indication and shall beinstalled complete with all accessories and ready foroperation. Wiring or capillary tube between sensorsand indicators shall be neatly run and clipped, whereappropriate, to support surfaces. Temperature sensorsshall be located to avoid the effects of thermalradiation from heaters or coolers, or be fitted withsuitable shields. A plugged 13mm diameter test holeshall be provided adjacent to each fixed thermometeror temperature sensor. All wiring shall conform to therequirements of the instrument manufacturer.

22.4 WATER SYSTEM THERMOMETERS

22.4.1 Thermometer pockets to BS 2765 shall beprovided in the flow and return connections to eachitem of heat exchanging equipment up to 30kWcapacity including air heater and air cooler batteries.The location and depth of thermometer pockets shallensure a true reading of the liquid temperature. Eachpocket shall be filled with sufficient approved heatconducting medium and be fitted with a plug or coverplate. Thermometers shall be provided as detailed inClause 22.3.2.

22.4.2 Where heat exchangers are larger than30kW capacity, dial type thermometers, as describedin Clause 22.3.3, shall be provided in the flow andreturn connections and be mounted in suitably locatedpockets. Stem immersion length and installation shall

be in accordance with the manufacturer'srecommendations. Thermo-meters shall be of similarconstruction and appearance to pressure gauges wherefitted and the instruments shall be neatly arranged.

22.4.3 Thermometer pockets shall be installed ineach of the following locations:

a) on the flow and return chilled water mains atthe entry to all plant rooms,

b) on the outlet connections of each heatexchanger,

c) on the flow and return connections to eachitem of water chilling plant,

d) on the main condenser water flow and return.

22.4.4 Wells for clinical type thermometers toBS 691 shall be installed for commissioning purposesat the water inlet and outlet to each evaporator of thewater chilling plant and in any other locationsindicated.

22.5 PRESSURE GAUGES

22.5.1 Gauges shall be Bourdon tube type toBS 1780: Part 2, 100mm diameter, except thoseinstalled in plant rooms which shall be 150mmdiameter.

22.5.2 Valved pressure gauges shall be installed ineach of the following locations:

a) at each pump suction and discharge, bothinstalled at the same height,

b) at positions close to other equipment items asindicated.

22.5.3 Gauges installed on chilled and coolingwater pipings shall be provided with a gauge cock ofthe straight pattern, ground plug type with leverhandle.

22.5.4 Each gauge shall have an adjustable pointer.Where gauges are provided in association with SectionThirteen—Water Pumps—of this Specification, thepointer shall be used to indicate the system statichead with the pumps at rest.

22.5.5 Each gauge shall have an enamelled mildsteel case with chrome bezel, a substantial glass face,and a phosphor bronze Bourdon tube. The dial faceshall be white with black scale graduations andnumbering.

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22.5.6 Two loose pressure gauges, suitable forconnection to valved tappings, shall be provided andhanded to the PM.

22.6 FILTER DIFFERENTIAL PRESSURE INDICATORS

22.6.1 Instruments shall be of the inclinedmanometer type or where indicated, a diaphragmoperated dial type differential pressure gauge of atleast 100mm diameter. A graduated scale shall beincorporated, on which the indication of maximumpressure differential shall be at no more than 75% offull scale. The initial resistance and final resistance ofthe filter shall be indelibly marked on or adjacent tothe instrument.

22.7 REMOTE READING THERMOMETERS

22.7.1 Air conditioning systems with a total designcooling capacity (not including stand-by) of 200kW orgreater, shall be provided with a multi-point remote

reading thermometer in addition to items specified inClauses 22.4.1 and 22.4.2, installed in the maincontrol panel to indicate, as appropriate, thetemperature in each of the following locations:

a) the fresh air connection,

b) the recirculation air duct(s),

c) the supply air duct(s),

d) before and after each air heater,

e) before and after each air cooler,

f) before and after each humidifying device,

g) main chilled water flow and return,

h) main condenser water flow and return.

A plugged or capped 13mm test hole or thermometerpocket, as appropriate, shall be provided adjacent toeach sensing point.

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Section Twenty-three—Automatic Controls

23.1 GENERAL

23.1.1 Automatic control systems shall be asindicated and shall form a complete and satisfactorysystem. All items of control equipment shall becompatible within any system, between systems andwith controlled equipment. As far as possible,equipment shall be provided by one manufacturer.

23.1.2 All flow and pressure switches, relaysnecessary for all interlocks, and any additional itemsdetailed including automatic dampers shall beincluded.

23.1.3 Automatic control valves and damperactuators shall incorporate position indicators.

23.1.4 Terminations to detecting devices, motorsand actuators shall be made off in flexible form topermit removal without disconnection and to eliminatevibration transmission.

23.1.5 The siting of items of control equipmentshall allow access for adjustment and maintenancepurposes. However, where items of control equipmentare mounted in accessible positions within normallyoccupied areas, the control items shall be providedwith means to deter unauthorised access.

23.1.6 Control systems shall be arranged such that,in the event of electrical power failure, pneumaticfailure, or other abnormal operating condition,inherent fail-safe features prevent potentiallyhazardous conditions arising.

23.1.7 All items of automatic control equipmentshall be identified with engraved black on whitelaminate labels to relate to a framed and glazedschedule which is to be fixed in a position approved bythe PM. Where no flat surfaces for fixing areavailable, the labels shall be securely attached withbrass chains.

23.2 AIR COMPRESSOR PLANT FOR PNEUMATICCONTROLS SYSTEMS

23.2.1 Pneumatic controls systems shall includenot less than two oil-free air compressor/receiverunits. Each such unit shall be provided with a filter,air drier, isolating, pressure reducing, relief, duplicatenon-return, and moisture drain valves. Where morethan two units are indicated, only two pressurereducing valves are required. Individual compressorswith separate free-standing receivers may be provided.Each compressor shall be fitted with an hours-runmeter.

23.2.2 The capacity of each compressor unit, wheretwo units are to be provided, shall be such that eachshall run for not more than 20 minutes in any 1 hour,and where three units are to be provided, not morethan 15 minutes in any 1 hour. The running timesshall be based on air consumption at times ofmaximum demand.

23.2.3 The system shall be arranged so thatautomatic change-over takes place if the selected aircompressor fails to start. On initial start-up, allcompressors shall start in sequence and may runtogether until the desired air pressure is reached.

23.2.4 Where three or more compressor units are tobe provided, only two air receivers capable ofoperating independently are required.

23.2.5 The control of each group of compressorsshall be such that in the event of the minimum setpressure not being maintained in the air receivers,then the number of compressors in operation shallprogressively and automatically increase to meet therequired pressure. A low pressure audible alarm shallbe provided.

23.2.6 Air receivers shall be to BS 5169 or BS EN 286,and may be vertically or horizontally mounted.

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23.2.7 A compressed air drier of the type indicatedand of the requisite capacity, shall be provided afterthe receiver, and shall be suitable for reducing thedew-point of the air to minus 5°C at the distributionpressure.

23.3 CONTROL EQUIPMENT FEATURES

23.3.1 Provisions for initial adjustments, (such ascontrol characteristic, wind and sun effect settings,set-back, boost etc), may be either concealed, tamperproof or housed within a lockable panel. Temperaturesetting scales shall be clearly marked in degreesCelsius. Adjusting devices shall provide ease ofsetting.

23.3.2 Time switches shall be of the self-startingsynchronous electric motor or electronic type and shallincorporate arrangements which, in the event of anelectrical supply failure, shall provide a reserverunning period of not less than 30 hours.

23.4 SENSING ELEMENTS

23.4.1 All controls and instruments shall beinstalled with adequate access and clearance to permitremoval of any item. Inspection of all wiringconnections shall be possible without removal of thecomponent.

23.4.2 All wiring, together with any necessarybrackets, supports, and immersion pockets fortemperature, pressure, and humidity sensors andindicators and any instrumentation detailed elsewhereshall be provided.

23.4.3shall:

Sensors for liquid temperature in pipework

a) be installed in pockets to permit withdrawalwithout draining the system,

b) be positioned to ensure total immersion withinthe liquid,

c) be positioned not less than 12 pipe diametersdownstream from a point of mixing.

23.4.4 Sensors for air temperature in ductworkshall be located in positions to most effectively sensethe measured condition and shall:

a) be protected from thermal radiation,

b) be positioned to avoid the effect oftemperature stratification, (eg whenpositioned for frost sensing, high temperaturelimit sensing, and average temperaturesensing),

c) where of the capillary averaging type, beinstalled on a suitable framework, andarranged to facilitate servicing,

d) where used for determining the dew-point, beof material and construction suitable for usein moist air.

23.4.5 Surface mounted temperature sensors shallbe positioned and fixed to ensure good thermalcontact.

23.4.6 Sensors for air temperature in spaces shallbe fixed in a representative position, (the preciselocation being approved by the PM):

a) in rooms at a height of approximately 1.5mabove floor level in the position indicated,

b) not subject to direct solar radiation,

c) not subject to the direct influence of airterminals,

d) not subject to local heat generation,

e) in the return air path where indicated.

23.4.7 Sensors for outside air temperature shall bepositioned generally where indicated, not subject tothe influence of direct solar radiation and local heatgains. Where special requirements are indicated, (egthe determination of solar gain, wind influence), themanufacturer's recommendations for positioningsensors shall be followed.

23.4.8 Humidity sensor locations shall be:

a) representative of the space in which thehumidity is being measured,

b) such that the air velocity is within the rangerequired by the sensor,

c) protected from airborne contaminants,

d) arranged to give convenient access forservicing,

e) adjacent to the space dry-bulb temperaturesensor unless otherwise indicated.

23.4.9 Sensors shall in all cases be installed inaccordance with the manufacturer's instructions.

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23.5 MOTORISED DAMPERS

23.5.1 Motorised dampers, which for the purpose ofthis Specification means dampers operatedautomatically by all forms of actuators, shall be of themulti-leaf type unless otherwise indicated.

23.5.2 A rigid mounting bracket shall be providedfor each damper actuator.

23.5.3 Electric motors for dampers shall be of thedirect-coupled direct-transmission type, clamped to theblade spindle and secured to prevent motor rotation.

23.5.4 Dampers shall be sized to provide a linearcharacteristic over the full operating movement of thedamper. Noise regenerated by any increase in velocityshall be attenuated if necessary to achieve thespecified noise levels.

23.5.5 Dampers shall be constructed in accordancewith Section Eight—Ductwork, Dampers and TerminalDevices—of this Specification.

23.6 AIR HEATER CONTROL

23.6.1 Unless otherwise indicated, the output of hotwater and steam air heater batteries shall be controlledby modulating valves having an authority as indicated.

23.6.2 Valves shall be capable of opening andclosing under full system pressure conditions andshall achieve tight shut-off. For liquid applications,let-by shall not exceed 0.5% of full duty for plug typevalves and 1.0% of full duty for shoe type valves.

23.6.3 Control valves shall be provided withisolating valves, located as appropriate, to permitremoval. The valve for the by-pass port of three-portcontrol valve shall be of the double regulating type inaccordance with Section Fifteen—Valves, Cocks andStrainers—of this Specification.

23.6.4 Electrical air heater batteries shall beenergised in three-phase balanced stages notexceeding 6kW per three-phase stage. Stages of notmore than 3kW may be single-phase. The number ofstages for multi-step control shall be as indicated.There shall be a time lag of not less than 5 secondsbetween energising/de-energising of successive stages.Where indicated, solid-state switching to provide fullymodulating control form 0% to 100% of full capacityshall be provided.

23.6.5 On electrical air heater batteries of 15kWand above, provision shall be made for the supply fanto continue to run for not less than 1 minute on plantshutdown.

23.6.6 Arrangements shall be made to ensure thatin the event of an electrical supply failure, or afternormal shutdown, the control system will recycle tothe 'OFF' position upon restoration of supply andbefore re-energising the heater.

23.7 AIR COOLER CONTROL

23.7.1 Unless otherwise indicated, the output ofchilled water cooler batteries shall be controlled bymodulating valves having an authority as indicated.Control valves shall comply with Clause 23.6.2 andshall be arranged in accordance with Clause 23.6.3.

23.7.2 For direct-expansion air coolers where thecooler duty exceeds 35kW, and elsewhere whereindicated, the cooler battery shall be arranged for stepcontrol in interlaced sections with isolating solenoidvalves on each section. The operation of the solenoidvalves shall be linked to off-loading of therefrigeration compressor(s) where appropriate.

23.8 HUMIDIFIER CONTROL

23.8.1 Unless otherwise indicated, the output ofsteam humidifiers using steam or HTHW as theheating medium shall be controlled by modulatingvalves complying with Clause 23.6.2. A spring-returnmechanism shall stop the flow of heating medium inthe event of control power failure.

23.8.2 Self-generative steam humidifiers of theelectrical immersion heater type or electrode boilertype shall be provided with the necessary equipmentto achieve control over steam output using thefollowing methods as indicated:

a) On/off control.

b) Multi-step control to provide the number ofstages indicated.

c) Solid-state switching to provide fullymodulating control from 0% to 100% of fullcapacity.

23.9 CONTROLS FOR WATER COOLING AND CHILLINGPLANT

23.9.1 Controls for refrigeration plant, includingchilled water and condenser water, are specified inSection Two—Refrigeration Plant—and SectionTwenty-Four—Starter and Control Panels—of thisSpecification. Additional control requirements shall beas indicated.

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Section Twenty-four—Starter and Control Panels

24.1 GENERAL

24.1.1 All grouped controls shall be enclosed in apurpose-made panel. Motor starters and controllers formounting in the panel shall comply withBS EN 60947-4-1. Panels shall provide theBS EN 60947-1 degree of protection indicated.

24.1.2 Purpose-made panels shall comply with therequirements for assemblies contained inBS EN 60439-1.

24.1.3 Normal service conditions for panels shall beas stated in BS EN 60439-1, unless otherwiseindicated. All items of equipment mounted on orwithin the panels shall be rated for these serviceconditions.

24.1.4 Electrical compartments and compartmentshousing control elements in air handling units, shallbe designed to exclude damp and dust and shall beprovided with an anti-condensation heater controlledby an ambient air thermostat with adjustable set-point.

24.2 PANEL ARRANGEMENT

24.2.1 Panels shall be sub-divided into separatecompartments for 'Main Incoming Power Section','Duty Section', 'Stand-by Section' and 'Control Section'or shall be compartmented as indicated. The internallayout and external appearance of panels shall beapproved by the PM before manufacture.

24.2.2 Access doors or covers to each compartmentof a panel shall be so arranged that access cannot bemade until an isolating device interlocked with eachdoor or cover is opened and all equipment accessiblethrough that door or cover is isolated. Unlessotherwise indicated, this requirement shall not applyto the 'Control Section' which shall be arranged topermit control adjustment while the plant isoperational. A purpose-made device shall be provided

for each panel supplied to enable a competentexaminer to override the interlock when the door orcover has been opened.

24.2.3 Equipment shall not be fixed to any coverwhich is removable for maintenance access purposes.Items of equipment fixed to a door shall be kept to aminimum and in any case shall not include heavycomponents or sensitive instruments. All wiring shallbe neatly arranged and secured.

24.3 MATERIALS AND CONSTRUCTION

24.3.1 The panel enclosure shall be rigidlyconstructed from suitably prepared and finished bestquality folded mild steel sheet of a minimum thickness2mm or of mild steel angle frame supporting sheets ofmild steel of a minimum thickness 1.25mm, or be aproprietary system of construction to the approval ofthe PM.

24.3.2 All panels shall be provided with hinged andlockable access doors or covers at the front of thepanel and/or back of the panel as required to facilitatemaintenance. Locks shall be cylinder type, providedwith two keys each, and shall be identical for allpanels on one project.

24.3.3 Doors shall be flush-fitting mild steel withfolded edges and welded corners of a minimumthickness 2mm with concealed non-ferrous hinges, orof alternative construction to the approval of the PM.Framework associated with doors shall be fitted withskinned foamed plastic dust protective strip orneoprene tube sealing gaskets.

24.3.4 Finished panels shall be without rough orsharp edges and shall present smooth surfaces. Allexposed screws, bolts and similar fastenings shall beprotectively plated.

24.3.5 Panels shall be finished externally with asemi-gloss stoved or cellulose enamel finish to colour00 A0 05 of BS 4800, or as approved by the PM.

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Internal surfaces and component mounting platesshall have a matt white finish. All surfaces shall beproperly prepared before final finishing.

24.3.6 Panels secured to a finish floor shall beprovided with a metal plinth. A metal plinth is notrequired with panels mounted on a raised builder'swork base. All panels shall be provided with fixingholes. Large panels or panels exceeding 75kg shall beprovided with detachable lifting eyes.

24.4 PANEL WIRING

24.4.1 Internal power wiring shall be identified bycolour code in accordance with BS 7671. Controlcircuit and other wiring shall be to BS 6231 withidentifying code extending to each cable terminationusing ferrules or other approved permanent means ofattachment. Secure fixing of all cable ends shall beensured by the use of purpose-made clamps, pinch-type terminals, crimped cable tags or other approvedtermination devices.

24.4.2 Panel wiring for electronic thermostatic andhumidity control sensors, and for any other items asnecessary, shall be in screened multicore flexible cable.Extra low voltage wiring and connections shall besegregated from those for higher voltages or beinsulated for the highest voltage present. Starterauxiliary contacts shall be volt-free.

24.4.3 Grouped terminal blocks of adequate sizeand capacity shall be provided for all cables leading toequipment outside the panel. A removable cover, orother facility such as a removable blank flat glandplate, shall be provided for the entry of incomingcables, conduits, trunking, etc, with means foreffective electrical bonding to the panel. Provisionshall be made for the earthing of all non-currentcarrying panel and equipment metalwork includingpanel door(s). All necessary electrical bonding shall beprovided together with an earthing terminal ofadequate size, positioned within the panel at the rearor bottom on a part which is not removable. Accessshall be provided for making connections to theearthing system.

24.4.4 Fuses shall be grouped and mounted so as tobe readily and safely accessible. Cartridge fuses shallcomply with the requirements of BS 88: Part 2. Fusesfor motor circuits shall be motor circuit fuse links withdual current ratings in accordance with BS 88: Part 1.

24.4.5 The control circuitry within panels shall bearranged such that each control system is separatelyprotected. For the purpose of this Clause, a 'control

system' shall be defined as that necessary to sustainan item of plant and/or control a zone. Stand-by plantshall have separately fused supplies.

24.5 IDENTIFICATION LABELS

24.5.1 Fuses, terminal blocks and all other items ofequipment within panels shall be suitably identifiedby means of clearly inscribed labels of a permanentnature attached or adjacent to them. All items on theouter surfaces of panels shall be identified withlaminated plastics labels engraved white-black-white.The full requirements of BS EN 60439-1: 1994 shall beprovided.

24.6 VENTILATION

24.6.1 The temperature rise in motor controlpanels shall not exceed the limits stated inBS EN 60439-1. Where automatic control items areinstalled, panel construction shall provide adequateventilation for internal heat dissipation. Provisionsshall be made to ensure that the internal temperatureis limited to 10°C above ambient.

24.7 INSTRUMENTS AND INDICATION

24.7.1 All indicating lamps, instruments andcontrols shall be, as far as is practicable, of the samemanufacture and style to provide uniformity ofappearance and facilitate maintenance. Externallyvisible equipment shall be flush-mounted and fixedsecurely to the faces of control panels. Internalequipment shall be fixed to purpose-made rails ormounting bars. All fixings shall incorporate shake-proof washers or other vibration resisting fastenings.

24.7.2 The colours and colour significance ofindicator lamps shall be in accordance withBS EN 60073, unless otherwise indicated. Where extralow voltage filament lamps are installed, they shall befed from a double-wound transformer complying withBS 3535. Permanent legible information shall beprovided adjacent to each indicator lamp to readilyidentify its function. Where indicated, facilities shallbe provided within the panel for remote alarmindication. Where indicated, a single fault indicator ata remote station, showing a fault condition on anyitem of plant, shall be fitted. A lamp test facility shallbe provided on all panels having four or moreindicator lamps.

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24.7.3 Lamps shall be provided with 'RUN' and TRIPPED' indication for each electric motor

and each electrical air heater battery. A lamp forTOWER ON' indication shall be provided on eachcontrol panel.

24.7.4 Ammeters shall have scales not less than70mm in length and shall indicate maximumoperating current is not less than 75% of total scalelength.

24.7.5 An ammeter shall be provided on the controlpanel for each electric motor over 7.5kW output andfor each electrical air heater battery.

24.7.6 Indicator lamps and instrumentation shallfunction with selector switches in the 'HAND' or'AUTOMATIC' position.

24.8 STARTERS AND CONTROL GEAR

24.8.1 Unless otherwise indicated, starters shallcomply with BS EN 60947-4-1. The 'rated duty' shallbe 'intermittent' and the class of intermittent duty ofthe starter shall be appropriate to its operatingconditions.

24.8.2 The following types of starters will beaccepted unless otherwise indicated:

a) Motors up to 0.75kW output, 240V, single-phase: direct-on-line.

b) Single speed motors up to 7.5kW output, 415V,three-phase: direct-on-line, star-delta or soft-start.

c) Single speed motors over 7.5kW output, 415V,three-phase: star-delta open or closedtransition, auto-transformer closed transition,rotor resistance, part-winding or soft-start.

For multi-circuit winding motors (partwinding), the starter shall start the motor onone set of windings and provide a reducedstarting current not exceeding 65% of fullvoltage locked-rotor current.

d) Multi-speed motors with independentwindings shall start on the low speed winding.

Electronic soft-start devices shall be in accordancewith Electricity Association Recommendation G5/3,the point of common coupling being regarded as theinput terminals to the starter.

24.8.3 For starters incorporating reduced voltagestarting, the change-over of voltage shall beautomatic. All reduced voltage starters shall have anadjustable transition time.

24.8.4 Starters shall be provided with a manuallyreset device for ambient temperature compensatedthermal overload protection on each phase and single-phase protection. Under-voltage release relays shall beprovided with time-delayed drop-off and, unlessotherwise indicated, shall not be arranged forautomatic restarting of the motor on restoration of themains voltage. Contactor operating coils shall bewound for not more than 240V and shall be suitablefor d.c. operation or rectified a.c. operation asindicated. Multi-speed motors shall be protected by athermal overload device in each circuit. Provision shallbe made for limiting the number of motor starts perhour, having due regard for operating requirements.

24.8.5 Every electric motor shall be provided withseparate control gear and starting equipment andshall be connected to a separate final circuit. Whereduplicate plant is provided, the starters for each plantshall be housed in a separate compartment of a panel.Where an item of plant is provided with duplicatemotors, the starters for each motor shall be housed ina separate compartment of a panel. For the purposesof this Clause, 'duplicate' items shall be defined as'stand-by' items provided to sustain operationalconditions in the particular system upon failure ornon-selection of the 'duty' item.

24.8.6 Where more than one refrigerationcompressor is provided, the compressor motor startersshall be housed in separate cubicles with separateelectrical protective devices. For refrigeration plant orcompletely packaged water chilling units, thecompressor motor starters may, at the discretion of thePM, be housed separately from the main starter andcontrol panel, but provision shall be made for anyelectrical interlocking which may be required betweenthe compressor motor switchgear and the starters forthe remainder of the plant.

24.9 AUTOMATIC CONTROL

24.9.1 For the control of electrical equipment whichis not interlocked, an 'ON/OFF' rotary snap switchshall be fitted on the front of the panel for each itemof plant. Where interlocks are required an 'ON/OFF'switch shall be fitted for the master and a 'HAND/OFF/AUTO' switch shall be fitted for each item ofdependent plant. The switch positions shall be clearlyindicated and each switch shall be clearly labelled toshow which item of plant it controls.

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24.9.2 With a switch in the'AUTO' position, the dependent item of plant shallstart automatically as required when the item switchis switched 'ON', and shall operate automaticallyunder the dictates of any controlling devices. Theoperation of the switch to the 'HAND' position shalloverride any controlling devices except those whichare necessary for the safe operation of the plant.Similarly, the operation of the master item switch to'OFF' with the dependent plant at 'AUTO', shall causeall plant to stop in sequence. (The sequence shall bearranged to ensure that the plant shuts down in asafe and logical way, eg. a fan may run on to removeheat from electrical heaters, or a chilled water pumpmay run on until refrigeration pump-down iscompleted to avoid freezing up).

24.9.3 For cooling and air conditioning plants, themaster item shall be the main air supply fan and/orchilled water pump(s) as appropriate. For systemswith direct-expansion air coolers, the starting of themain air supply fan shall, under automatic workingconditions, allow all other plant to start in sequenceand as required by automatic control. Similarly, forchilled water systems, the master item shall be thechilled water pump(s) and their operation shall, underautomatic working conditions, allow the refrigerationplant etc. to start. Where there are both air and watersystems, the main air supply fan shall be the masteritem for the air handling plant and the airtemperature and humidity controls; the chilled waterpump(s) shall be the master item for the waterhandling plant, the refrigeration plant and the watertemperature controls and water flow switch.

24.9.4 For each electrical air heater battery, a'HAND/OFF/AUTO' rotary switch shall be provided.Associated with the 'HAND' setting of the switch,there shall be a second rotary switch giving manualcontrol of the heating stages independently ofautomatic control.

24.9.5 The refrigeration control circuit shallprovide start facilities to equipment within therefrigeration system, giving consideration tocomponent protection, and in the following sequence:

a) For chilled water systems the chilled waterflow, and for direct-expansion air coolingsystems the air flow, must first be establishedand verified.

b) The condenser cooling medium flow must thenbe established and verified or, wherecondenser head pressure control is provided,must be available under the dictates of thiscontrol. The head pressure control shall becapable of effecting a gradual increase ofcondenser heat rejection.

c) The refrigerant liquid feed valve shall thenopen and the compressor be allowed to starton minimum capacity. Gradual increase ofcapacity shall be dictated by the duty controlfacility. When more than one compressor isinstalled, arrangements shall be made to startin time-delayed sequence and as required byload control. A switch shall be provided toenable any machine to be selected manuallyin lead-lag arrangements.

d) Automatic shutdown of the refrigeration plantshall normally be in the reverse order to thestart procedure. When a pump-down circuit isinstalled, precautions must be taken to avoidfreezing within the evaporator of a waterchiller or short cycling of the compressor.

24.10 TESTING

24.10.1 Control panels shall be fully equipped, wiredand tested before delivery to site. A functional testsimulating operation of the complete panel shall beperformed before despatch. This test shall bewitnessed by the PM unless otherwise agreed, and atest completion certificate issued. The Contractor shallarrange for site commissioning of the panel to thesatisfaction of the PM.

24.11 SCREENING AND INTERFERENCE

24.11.1 Screening and interference requirementsshall be in accordance with Section Twenty-Five -Electrical Equipment and Wiring of this Specification.

94 October 1997


Section Twenty-five—Electrical Equipment andWiring

25.1 SCOPE

25.1.1 Unless otherwise indicated, the Contractorshall provide and install all electrical equipmentnecessary for the complete installation and carry outall wiring from point(s) of supply shown on thedrawing(s).

25.1.2 The Contractor shall be responsible for theaccuracy of all drawings and wiring diagramsprovided by him and for the correct internal wiring ofall pre-wired equipment supplied for the contract.

25.2 GENERAL

25.2.1 Unless otherwise indicated, all electricalequipment shall be suitable for use in ambienttemperatures up to 40°C with an average over a 24hour period of 35°C and relative humidities up to 90%.Equipment shall be proof against atmosphericcorrosion, including saline air where indicated, andmaterial shall not be susceptible to mould growth orattack by vermin.

25.3 ELECTRIC MOTORS

25.3.1 Each motor shall comply with theappropriate Parts of BS 4999, BS 5000, andBS EN 60034 and shall be of such a size and type tostart and drive the equipment under normalconditions of service without overloading.

25.3.2 Motors greater than 0.75kW output shall besuitable for operation from a three-phase supplyunless otherwise indicated or agreed with the PM.

25.3.3 Nameplates shall be positioned so that theyare readable from normal access positions.

25.3.4 All motors shall be continuously rated andshall have insulation in accordance with BS 2757 withClass F as a minimum unless otherwise indicated.Classes Y and A, shall not be used. Temperatures shallbe measured in accordance with BS 4999: Part 102.

25.3.5 Motor enclosures shall have an Index ofProtection to BS EN 60529 as indicated. Motorscontinuously exposed to the weather shall haveenclosures to IP54 of BS EN 60529 or as suitable forthe application.

25.3.6 Each electric motor shall be provided with alocal means of complete isolation operable under load.

25.3.7 Motors arranged for automatic starting shallhave a label of durable material, not less than150mm x 100mm in size, permanently affixed in aprominent position and having, in clearly inscribedcharacters, the legend:

DANGER. THIS MOTOR IS AUTOMATICALLYCONTROLLED AND MAY START WITHOUTWARNING. ISOLATE BEFORE INSPECTION.

25.4 ELECTRICAL WIRING

25.4.1 The electrical wiring system and provisionsfor equipment isolation shall be as indicated and shallbe in accordance with the relevant sections of DEOSpecification 034.

25.5 SCREENING AND INTERFERENCE

25.5.1 All apparatus, where the normal operationis such that interruption of low frequency or directelectrical currents occurs, shall be fitted with means ofsuppressing the radio and television interference socaused. The equipment and methods to be used indetermining the level of radio interference shall be asspecified in BS 727 and the limits of interference shallin all cases be those specified in BS EN 55014.

October 1997 95


Section Twenty-five—Electrical Equipment and Wiring

25.5.2 In order to avoid corruption of the controland building management system operation byelectrical interference, all wiring shall be of a suitabletype and shall be installed to minimise coupling ofelectro-magnetic and electro-static interference to lowvoltage signal and data wiring. The preferred methodof achieving this shall be by ensuring a physicalseparation of greater than 50mm between the power

supply cables and the signal and data cables. Wheremixed wiring is unavoidable, braided screened mainscable dressed close to metalwork shall be used. TheContractor shall identify his proposed method ofinstallation to avoid such corruption and interference.

25.5.3 The automatic control systems shall beprotected from radio frequency interference such asthat caused by the operation of any radio transmitter.

96 October 1997


Section Twenty-six—Inspection, Testing andCommissioning

26.1 DEFINITIONS

26.1.1 For the purpose of this Specification thefollowing definitions shall apply:

Testing

a) Off-site Testing. Tests carried out on items ofequipment at manufacturer's works orelsewhere.

b) Site Testing. Tests on static plant and systems(eg inspection and testing of welds, hydraulicpressure testing of pipework etc).

c) Performance Testing. The measuring andrecording of the performance of thecommisioned installation under varying plantloading utilising artificial loads.

Preliminary Checks

Checks to ensure that all systems and systemcomponents are in a satisfactory and safe conditionbefore start-up.

Commisioning

The advancement of an installation from the stage ofstatic completion to full working order to specifiedrequirements.

Commissioning includes the setting to work andregulation of an installation.

a) Setting To Work. The process of setting a staticsystem into motion.

b) Regulation. The process of adjusting the ratesof fluid flow and heat transfer to tolerancesstated in the relevant CIBSE CommissioningCodes or as otherwise indicated.

26.2 GENERAL

26.2.1 Preliminary checks, cleaning, setting towork and regulation of the individual systems shall bein accordance with the relevant CIBSE CommissioningCodes, BSRIA publications listed below and otherdocuments as indicated:

CIBSE Commissioning Codes (Series A, R and W)BSRIA Application Guide AG1/91

Commissioning of VAV Systems in Buildings

BSRIA Application Guide AG8/91Pre-commission Cleaning of Water Systems

BSRIA Application Guide AG2/89The Commissioning of Water Systems inBuildings

BSRIA Application Guide AG3/89The Commissioning of Air Systems inBuildings

HVCA A practical guide to ductwork leakagetesting—DW/143.

Particular attention shall be given to the permittedtolerances in the above codes.

26.2.2 The entire commissioning and performancetesting of the installation shall be undertaken by oneof the approved Commissioning Specialists indicated.The Contractor shall at all times be responsible for thesupervision of the Commissioning Specialist's workand shall ensure satisfactory completion ofcommissioning and recording of results.

26.2.3 Testing and Commissioning

26.2.3.1 The PM shall be given the opportunity towitness all tests. Suitable advance written notice oftests shall be given.

26.2.3.2 Any defects of workmanship, materials,performance, maladjustments, non-compliance withthis Specification or other irregularities which become

October 1997 97


Section Twenty-six—Inspection, Testing and Commissioning

apparent during the tests or commissioning shall berectified by the Contractor, at his own expense, untilthe whole Works is free from defects and in fullworking order to the complete satisfaction of the PM.

26.2.3.3 All instruments shall be provided by theContractor or his Commissioning Specialist, andevidence of the accuracy of the test instruments shallbe provided. Test methods shall be demonstrated tothe PM where required.

26.2.3.4 The Contractor shall submit to the PM aschedule detailing the equipment which he or hisCommissioning Specialist proposes to use in thetesting and commissioning of the services and the testmethods to be employed.

26.2.3.5 Testing and commissioning of major items ofproprietary plant or specialist equipment shall becarried out by the manufacturer's personnel andwitnessed by the Commissioning Specialist. The PMshall be advised of such activities.

26.2.3.6 Test results shall be recorded onCommissioning Certificates provided andcountersigned by the PM.

26.3 CLEANING

26.3.1 Pre-operational chemical cleaning of watersystems shall be carried out where indicated. Forchemical cleaning requirements see ParticularSpecification and BSRIA Application Guide AG8/91.

26.3.2 Ductwork systems shall be cleaned byblowing out using the supply air fan. No fan shall bestarted until cleaning is to commence.

26.3.3 Cleaning shall be completed before theconnection of terminal units and fittings.

26.3.4 Duct spigot ends shall be temporarily fittedwith securely fixed fine mesh covers to collect airborneparticles for disposal as directed by the PM.

26.4 TESTING

26.4.1 Off-site testing

26.4.1.1 Where British Standards stipulate testing ofitems of equipment to demonstrate compliance, theseshall be carried out at the manufacturer's works orelsewhere as appropriate. In all cases, test certificatesshall be submitted in duplicate to the PM and beincluded in the Record Documents. In certain cases,where appropriate, type test certificates will beaccepted as indicated.

26.4.1.2 Test certificates shall serve as a record thatthe item referred to has been shown under test tomeet the requirements of this Specification and/orBritish Standards as applicable and shall be dated,numbered and clearly referenced to the item tested bymeans of serial, chassis, or other manufacturer'sreference number permanently marked in aconspicuous position.

26.4.1.3 Where an individual inspection or test takesplace at the manufacturer's works, a representative ofthe Contractor shall normally be required to bepresent.

26.4.1.4 Tests shall be made at the Contractor's orsupplier's premises, on samples of materials andcomponents to be installed in the Works in anymanner deemed necessary by the PM to ensureconformity with this Specification. The results of suchtests shall in no way relieve the Contractor of hisresponsibilities to ensure that all materials andcomponents used in the Works are entirely suitable forthe applications and conditions of operation.

26.4.1.5 All control panels shall be checked at themanufacturer's works and certified to comply withSection Twenty-Four—Starter and Control Panels—ofthis Specification prior to despatch. Functional checksshall also be carried out at the manufacturer's worksto ensure that all inter-locking and sequencing is inaccordance with the performance requirements. Testjumpers, where fitted, shall be removed at the end ofthe checking. Documentary evidence of compliancewith short circuit ratings shall also be provided.

26.4.2 Site Testing

26.4.2.1 The Contractor shall be responsible for sitetesting of static systems in order to ensure safeoperating conditions consistent with designperformance. Site testing shall include inspection andtesting of welding and brazing, pressure testing forsoundness of hydraulic systems and air leakagetesting of ductwork systems.

26.4.2.2 Unless otherwise indicated, fuel, water(other than treated water), and electricity necessaryfor the operation of the plant during site testing willbe provided free of cost to the Contractor.

26.4.2.3 After completion of pipework cleaningoperations and before the application of thermal oracoustic insulation, each water distribution systemshall be charged with clean water and then subjectedto an hydraulic test of 1.5 times the working pressure.There shall be no loss of pressure during a period ofnot less than 30 minutes. To suit particular

98 October 1997



installations, hydraulic test(s) shall be carried out onthe complete system or in sections as directed by oragreed with the PM. Where sectional testing isadopted, a final hydraulic test will be necessary. Anyitems of equipment set to operate at or below the testpressure shall be isolated or removed prior to theapplication of this test. On completion of testing andcleaning operations, systems shall be protected againstinternal corrosion until the water treatment plant isput into service.

26.4.2.4 Medium and high pressure/velocityductwork systems shall be tested for air leakage inaccordance with HVCA Specification DW/142 usingmethod described in HVCA publication DW/143. Lowpressure/velocity ductwork systems shall be tested forair leakage by the same methods where indicated.

26.4.2.5 Installations or sections of air or waterdistribution systems which will be embedded in thestructure or concealed in permanently sealed ducts,trenches, roof spaces etc, shall, in addition to theabove specified tests, be individually tested as theyare installed and before being embedded or concealed.

26.4.2.6 Vibration transmission-break equipmentshall be thoroughly checked for correct installationand alignment, and shall be statically tested to ensurethat suspensions and/or connections operate asintended.

26.4.2.7 The Contractor shall be responsible forcorrecting any unacceptable vibration apparent duringplant operation.

26.4.2.8 Wiring terminations to control equipmentshall be checked for compliance with the wiringdiagrams, and for interlocking with other equipment.Any faults shall be rectified unless associated withwiring carried out under a separate Contract in whichcase they shall be recorded and the details passed tothe PM for action.

26.5 COMMISSIONING OF WATER AND AIRDISTRIBUTION SYSTEMS

26.5.1 General

26.5.1.1 The Contractor shall be responsible for fullycommissioning each system.

26.5.1.2 The entire commissioning procedure shall beperformed to the satisfaction of the PM and theContractor shall demonstrate that the installation ofany portion thereof, which has been set to wTork,complies with the requirements of this Specification.

26.5.1.3 A Legionella Risk Assessment shall be madeon completion of the installation.

26.5.1.4 Installations subject to the PressureSystems and Transportable Gas ContainersRegulations shall have a Written Scheme of Inspectionprepared by a Competent Person.

26.5.2 Distribution Systems—Water Piping

26.5.2.1 Prior to regulation, pipe systems shall bemodified as necessary and in accordance with goodpipework practice, so that flow rates with all valvesfully open are within 50% above the design values.

26.5.2.2 After all water systems have been regulated,the final settings are to be recorded on theCommissioning Certificates provided.

26.5.3 Distribution Systems—Ductwork

26.5.3.1 After the air systems have been regulated,all dampers shall be labelled and quadrants indeliblymarked to show the correct setting. Filters shall bechecked and where necessary, changed or cleaned. ThePM shall decide whether a filter change or cleaning isnecessary, in accordance with Section Four—AirFilters—of this Specification.

26.5.3.2 Regulation of a system shall be achievedinitially by change of drive pulleys. Any minorregulation may be obtained by adjusting the fandischarge damper. Additional dampers which may berequired for correct air balancing, together with theassociated works, shall be provided.

26.5.3.3 After all air systems have been regulated,the final settings are to be recorded on theCommissioning Certificates provided.

26.6 COMMISSIONING OF SPECIALIST EQUIPMENT

26.6.1 The Contractor shall ensure that allcommissioning work carried out on specialistequipment by the manufacturer's personnel iscompleted to his satisfaction, to the satisfaction of theCommissioning Specialist and to the satisfaction of thePM.

26.7 COMMISSIONING RESULTS

26.7.1 All equipment data and commissioningresults shall be recorded by the Contractor on theCommissioning Certificates provided. Each certificateshall be endorsed by the PM or his nominated witnessunless otherwise indicated. The scheduled items andstated commissioning procedures shall be interpreted

October 1997 99



by using the appropriate clauses of this Specification,any supplementary specification and the designrequirements of the drawings. All certificates shall beserially numbered for retention in the CommissioningData Section of the Operation and Maintenance LogBook.

26.7.2 Prior to completion of the CommissioningCertificates, the Contractor shall obtain writtenconfirmation from specialist manufacturers that theircommissioning tasks are complete and the equipmentis operating correctly. A statement recording the levelof performance shall be included where appropriate.

26.8 PERFORMANCE TESTING

26.8.1 Where indicated, the Contractor will berequired to demonstrate by measurement andrecording that an installation, or part of aninstallation, functions correctly without need ofadjustment and is capable of maintaining internalenvironmental conditions within specified limits undervarying plant loading. All tests shall be witnessed bythe PM or other authorised representative.

26.8.2 Unless otherwise indicated, specialisedinstallations including computer rooms, clean roomsand other close-control applications, will be required toachieve satisfactory system performance whensubjected to artificial internal and external loads inaccordance with the procedure laid down in theCommissioning Certificates provided by the PM.

26.8.3 Comfort and process air conditioninginstallations will be required to achieve satisfactorysystem performance in accordance with the procedureindicated.

26.8.4 The Contractor shall ensure that allperformance test requirements are achieved and theplant is continuously operated for a minimum periodof 24 hours before tests are witnessed.

26.8.5 The Contractor shall be satisfied andconfirm to the PM, giving a minimum period of 24hours notice, that the installation is ready for witnessof performance testing.

26.8.6 The Contractor shall be responsible for thesupply, fixing, connection and safe operation ofsufficient temporary artificial heat load equipmentand any instrumentation necessary to demonstratesystem performance, and for subsequent disconnectionand removal from site when the PM is satisfied thattests are complete. The Contractor shall submit hisproposals for the performance tests to the PM forapproval 6 weeks before start of commissioning.

26.8.7 For the duration of performance tests, theContractor shall ensure that all qualifiedcommissioning and other specialist personnel arepresent and available at all times to make anynecessary immediate adjustments and repairs.

26.8.8 Measurements and records of performancetest results are to be entered on the CommissioningCertificates provided by the PM and handed to the PMwithin the time period indicated. Copies of the resultsshall be retained on site by the Contractor and beavailable to the PM or other official representative.

26.8.9 The Contractor shall subject the entire plantto a total continuous run of the duration indicated toensure that all apparatus, materials and systems areworking properly; that all controls, safety devices,operating services and all units are properly adjustedand operating correctly; that design temperatures inthe piping system and throughout the air systems areestablished; that the systems provide the requiredinternal conditions and to assure himself that thedesign intent is achieved before demonstration to thePM. The performance shall be evaluated duringenvironmental conditions prevailing at that time.

26.8.10 The tests shall be made at the direction ofthe PM. Should the plant not be in proper operatingcondition, the PM reserves the right, where defectspersist, to employ others to carry out remedial workand put the systems in proper working order, at theContractor's expense.

26.8.11 The Contractor shall provide a temporaryinstallation of portable recorders where indicated andsimultaneously record temperatures and humiditiesfor summer and winter design conditions. The locationof test instruments shall be approved by the PM. Thecorresponding external conditions shall also berecorded whilst tests are in progress. The capacity ofrefrigeration plant, (including components thereofsuch as condensers, evaporators, cooling towers, etc.),and other air handling plant shall also bedemonstrated and recorded.

26.8.12 Individual room temperatures shall bemeasured by mercury-in-glass thermometers located1.5m above floor level at points unaffected by theinfluence or draughts or direct radiation from hot orcold surfaces.

26.9 SOUND LEVEL MEASUREMENTS

26.9.1 Readings shall be taken to ensure that therequired noise ratings are not exceeded.Representative areas will be selected by the PM.

100 October 1997



26.9.2 The acoustic performance of atmosphericsilencers, items of plant where limitations onpermitted noise levels are specified and the noisetransmission from plant room areas shall bemeasured, recorded and the results assessed asindicated.

26.9.3 Wherever necessary, when measuring roomsound levels, normal continuous background noisefrom sources other than the installation shall be takeninto account. Measurements relating to overhead

terminals shall be taken directly below each terminalat 1.7m above floor level, and for sidewall terminals,1m horizontally from each terminal and 1.7m abovefloor level.

26.9.4 Results of octave band analysis shall besubmitted on noise rating curve charts for eachindividual space.

26.9.5 Tests shall be carried out using a soundlevel meter, with frequency analyser, meeting therequirements for BS EN 60651: 1994.

October 1997 101


Section Twenty-seven—Maintenance andOperation Procedures and Documents

27.1 INSTALLER MAINTENANCE PROCEDURES

27.1.1 Where indicated, the Contractor shallprovide Installer Maintenance. Installer Maintenanceshall mean undertaking all compre-hensive plannedmaintenance and operation procedures and activitiesfor a period of 12 months unless otherwise indicated.The period of Installer Maintenance shall followacceptance of the installation.

27.2 INSTRUCTION PROCEDURES

27.2.1 The Contractor shall provide a properlysequenced programme to ensure that all plant,equipment and systems are fully and satisfactorilydemonstrated to the personnel nominated by the PM.

27.2.2 The programme shall be submitted to thePM for approval.

27.2.3 Instruction procedures shall includestarting, stopping and emergency procedures, routineadjustment of plant and day-to-day maintenance andservicing.

27.3 MAINTENANCE AND OPERATION DOCUMENTS

27.3.1 The Contractor shall provide the PM withfully illustrated and documented Maintenance andOperation Instruction Manuals. Unless otherwiseindicated, these shall be submitted 1 month beforecertified acceptance of the installation. The number ofcopies shall be as indicated.

27.3.2 Draft maintenance and operating documentsshall be submitted to the PM for approval not lessthan 1 month before the start of commissioning.

27.3.3 Where indicated, planned maintenance andoperation detail sheets and log book pages shall becompleted for the particular installation and itscomponent parts, and shall include the testing,

commissioning and performance testing details andmeasurements. Blank copies of the Authority'splanned maintenance data sheets will be provided freeof charge.

27.3.4 The Maintenance and Operation InstructionManuals shall include:

a) indexing of Installed' drawings and testcertificates,

b) general descriptions of all systems installed,

c) setting up and operating instructions for allequipment and systems installed and foremergency operation,

d) control sequences for all systems installed,

e) copies of all Commissioning Certificates,

f) frequency and details of routine maintenancerequirements for all plant and equipmentshown on a set of schedules produced for thispurpose,

g) fault-finding charts for each plant and system,

h) manufacturers' literature, test certificates,detailed drawings and electrical circuitdetails, printed operation and maintenanceinstruc-tions, for all specific items ofequipment and plant supplied and systemsconsisting of such equipment and plant.

j) schematic drawings of each system indicatingthe principal items of plant and equipmentwith the number code of each item indicated.

k) spare parts lists and recommended spareparts holdings.

102 October 1997

Specification 037 Section Twenty-seven—Maintenance and Operation Procedures and DocumentsAir conditioning, air cooling andmechanical ventilation for buildings

show valves and dampers with number codesrelated to schedules of equipment andInstalled' drawings,

indicate the size of all pipework andductwork,

show design volume flow rates and operatingtemperature ranges for all fluid distributionsystems.

October 1997 103

27.3.5 The documents shall be printed on goodquality paper and encased in A4 size, plastic coveredloose-leaf ring binders, with hard covers. Drawingsshall be A4 size or reduced to A4 size where necessary.

27.3.6 The Maintenance and Operation InstructionManuals shall be commenced in draft form as soon asthe working drawings are in hand.

The schematic drawings shall:

All drawings shall comply with the requirements ofclause 1.9.3.4 of this specification.

a)

b)

c)


Schedule No. 1: Information for the TendererSupplied by the Design Office

This first page of Schedule No. 1 gives an overall indication of the scope of the proposed installation. Thefollowing pages give more detailed information of the requirements.

October 1997 * Delete, complete or continue on separate sheet as necessaryNOTE: If more than one 'Page 1 ' is used, they are to be numbered 1A , 1B, etc

Page 1 of 17


Schedule No. 1 Contract No.

Clause *Item *Options/Requirements

October 1997 * Delete, complete or continue on separate sheet as necessaryNOTE: If more than one 'Page 2' is used, they are to be numbered 2A, 2B, etc

Page 2 of 17



Clause *ltem *Options/Requirements


Page 3 of 17





Page 4 of 17




Page 5 of 17





Page 6 of 1 7





Page 7 of 17


Schedule Mo. 1 Contract No.



Page 8 of 17





Page 9 of 17





Page 10 of 17




Page 1 1 of 17October 1997 * Delete, complete or continue on separate sheet as necessaryNOTE: If more than one 'Page 1 1 ' is used, they are to be numbered 1 1 A, 1 1 B , etc



October 1997 * Delete, complete or continue on separate sheet as necessaryNOTE: If more than one 'Page 12 ' is used, they are to be numbered 12A, 12B, etc

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Page 1 4 of 17





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Approved Commissioning Specialists(Clause 26.2.2)

The entire commissioning and performance testing of the installation shall be undertaken by one of the firmslisted below. Another firm may be nominated by the Contractor provided they have the appropriate expertise inthe works sections listed below and are approved by the PM.

NAME ADDRESS

COMMISSIONING WORK SECTIONS

The reference numbers given are taken from 'A Common Arrangement for Specifications and Quantities' producedby the Co-ordination Committee for Project Information (CCPI).

GROUP

T

U

V

W

Mechanical heating/cooling/ refrigerationsystems

Ventilation/air conditioning systems

Electrical supply/power/ lighting systems

Control systems

WORK SECTION


Page 17 of 17


Schedule No. 2: Information to Be Supplied bythe Tenderer

Section 2—Refrigeration Plant

Machine No.

Compressor (s) :

Identification Ref.Number of CompressorsMake

Cat No. or Ref.Output at Maximum Ambient Conditions ........ kWRefrigerant R ........Method of StartingFull Load Curren ........ AStarting Current ........ AMotor Output at Design Load ........ kWMethod of Capacity ControlFrequency Band (Hz): 125 250 500 1000 2000 4000 8000Sound Power Level (dB) at 1m ........ ........ ........ ........ ........ ........ ........Standards of Construction ....................................................Country of Origin ....................................................

October 1997 Schedule No. 2—Page 1 of 36NOTE: If more than one V is used, they are to be numbered 1B, etc

Specification 037 Schedule No. 2 Contract No.Air conditioning, air cooling andmechanical ventilation for buildings

Section 2—Refrigeration Plant (cont)

Machine No.

Absorption Machine(s):

Identification Ref.Number of machines

(single/double effect)Cat No. or Ref.Output at Maximum Ambient ConditionsPrimary Heating MediumSteamHot WaterDirect FiringSolution Pump MotorRefrigerant Pump MotorChilled Water Flow TemperatureChilled Water Return TemperatureCooling Water TemperatureChilled Water Flow RateCooling Water Flow RateAutomatic DecrystalizationStandards of ConstructionCountry of OriginCoefficient of Performance (CoP)

October 1997 Schedule No. 2—Page 2 of 36NOTE: If more than one 'page 2' is used, they are to be numbered 2A, 2B, etc

kW

bar°C ........ bar

kWkW°C°C°Ckg/skg/s


Section 2—Refrigeration Plant (cont.)

Machine No.

Evaporator (s):

Identification Ref.MakeTypeCat No. or Ref.

Shell MaterialEnd Cover MaterialTube MaterialTube Plate MaterialIs 'In Situ' Tube Replacement Possible?Refrigerant ControlStandards of ConstructionCountry of Origin

Machine No. .

Air Cooled Condensers(s):


Fan Type and No. Off .................................................................................Frequency Band (Hz): 125 250 500 1000 2000 4000 8000Sound Power Level (dB) at 1m ........ ........ ........ ........ ........ ........ ........Support Structure, etc. FinishCasing Material and FinishMethod of Condenser Pressure ControlFan Speed ControlStandards of ConstructionCountry of Origin

October 1997 Schedule No. 2—Page 3 of 36NOTE: If more than one 3' is used, they are to be numbered 3A, 3B, etc



Machine No.

Evaporative Condensers(s):


Fan Type and No. Off .................................................................................Frequency Band (Hz): 125 250 500 1000 2000 4000 8000Sound Power Level (dB) at 1m ........ ........ ........ ........ ........ ........ ........Condenser Coil Material and FinishCasing Material and FinishSump Material and FinishFan Impeller Material and FinishFan Casing Material and FinishMethod of Condenser Pressure ControlStandards of ConstructionCountry of Origin

Machine No.

Shell & Tube Type Condenser(s):


Shell MaterialTube MaterialWater Box MaterialMethod of Condenser Pressure ControlStandards of ConstructionCountry of Origin




No.

Dry Coolers (Air-Cooled Fluid Coolers):

Identification Ref.MakeCat No. or Ref.

October 1997 Schedule No. 2—Page 5 of 36NOTE: if more than one 'page 5' is used, they are to be numbered 5A, 5B, etc

MakeTypeNumber

Fan

Fan ImpellerMaterialFinish

Fan Casing MaterialFan Casing FinishTube MaterialFin MaterialFrame Material and FinishCasing MaterialCasing FinishFan Output Power (Total)Full Load Current (Total)Starting Current (Total)Frequency Band (Hz):Sound Power Level (dB) at 1mDesign Entering Fluid TemperatureDesign Leaving Fluid TemperatureDesign Ambient Dry-Bulb TemperatureMethod of Capacity ControlCountry of Origin

125 250 500 1000 2000 4000 8000

phAA

kW

°C°C°C

Specification 037 Schedule No. 2 Contract No._Air conditioning, air cooling andmechanical ventilation for buildings


Fan Impeller Material and FinishFan Casing Material and FinishFan Output Power (Total)Full Load Current (Total)Starting Current (Total)Frequency Band (Hz): 125 250Sound Power Level (dB) at 1m ........ ........Design Entering Water TemperatureDesign Leaving Water TemperatureDesign Ambient Wet-Bulb TemperatureCasing Material and FinishPacking Material and FinishInsect Repellent MeasuresSump Material and FinishSump Immersion HeaterDrift Eliminator Material and FinishDrift Eliminator EfficiencyMethod of Capacity ControlWater Treatment ArrangementsCountry of Origin

October 1997 Schedule No. 2—Page 6 of 36NOTE: If more than one 'page 6' is used, they are to be numbered 6B, etc

No.

500 1000 2000 4000 8000

ph .......................kWAA

°C°C°C

MakeTypeNo. Off

Cooling Tower(s):

Identification Ref.Make

TypeCat No. or Ref.

Fan


Section 3—Fans (For Air-Cooled/Evaporative Condensers, Dry Coolers and Cooling Tower Fans, see pi to 5)


Performance:VolumeTotal PressureExternal Static PressureTotal EfficiencySpeed

Motor Output at DesignLoadNo. of Phases/Method of StartingFull Load CurrentStarting CurrentFrequency Band (Hz): 125 250 500 1000 2000 4000 8000Sound Power Level (dB) at 1m ........ ........ ........ ........ ........ ........ ........Attenuator:

MakeGenerated Noise .......... dBInsertion Loss .......... dB

Limits of Vibration SeverityCentrifugal Blade FormCentrifugal Guide Vane Relationship

Between Spindle and Air FlowAxial Flow Fan Casing MaterialAxial Flow Impeller MaterialIn Line/Mixed Flow Casing MaterialIn Line/Mixed Flow Impeller MaterialPropeller Fan Elements FinishPropeller Fan Weather Protection LevelRoof Extract Unit Housing

Material and FinishRoof Unit Discharge Outlet, etc.

Non-corrosive FinishCountry of Origin

October 1997 Schedule No. 2—Page 7 of 36NOTE: If more than one 'page T is used, they are to be numbered 7A, 7B, etc

Fan No. ......................................

........m3/s

...........Pa

...........Pa

............%

....... rev/s

......... kW

............A

............A



Section 4—Air Filters

IdentificationRef

Make andCountryof Origin

Type Cat Noor Ref.

Medium Grade Design Quantities Pressure Drop

Air VolumeFlow Rate

FaceVelocity

Initial(Pa)

Final(Pa)

Type TestCertificates

(Attached (A)None (N)

Section 5—Air Heater and Cooler BatteriesSchedule batteries in the following order; hot water(H), steam(S), electrie(E), chilled water(C) and directexpansion (D)

IdentificationRef

Make andCountryof Origin

TypeH/S/E/C/D

Cat Noor Ref.

Outputcapacity

(kW)

Airvolume

flow rate(m3/s)

Pressure Drop Electric

Air(Pa)

Water/Stream(kPa)

SurfaceTempMax

batteries DX coils

Largeststep(kW)

Refrigerant(R)

DefrostInc (1)

Exc (E)




Section 6—Humidifying Plant

Steam Humidifiers:

IdentificationRef

Make and TypeCountryof Origin

Cat Noor Ref.

Humidifyingcapacity(kg/s)

Steam

Inletpressure

(bar)

Capacity(kg/s)

Electrical

Phase Power(kW)

Controlmethod

No. ofsteps

Full loadcurrent (A)

Ultrasonic Humidifiers:

IdentificationRef

Make and TypeCountryof Origin

Cat Noor Ref.

Humidifyingcapacity(kg/s)

Watertreatment

Phase Primary(V)

Electrical

Secondary(V)

Power cons.(W)

Eliminatorplates




Section 7—Air Handling Units

Unit No. 1 Unit No. 2 Unit No. 3


Identification Ref.

Make

Type

Cat No. or Ref.

Pre-Heating Capacity

Re-Heating Capacity

Heating Medium

Cooling Capacity

Cooling Medium

Humidification Capacity

Humidification Medium

Air Volume Flow Rate

Fan —Power—Starting Method—Starting Current—Full Load Current

Damper Leakage (Max)

Sound Power Level (dB), at 1m

125250500

Frequency Band (Hz) 1000200040008000

Country of Origin

kW

kW

kW

kg/s

m3/s

kW

AA

%

kW

kW

kW

kg/s

m3/s

kW

AA

%

kW

kW

kW

kg/s

m3/s

kW

AA

%



Section 8—Ductwork, Dampers and TerminalDevicesSystems:

Section 8—Ductwork, Dampers and TerminalDevicesFire Dampers:

Element Manufacturer Country of Origin Type

Sheet MetalDuctwork:Material:

PlasticsDuctwork:

BendableDuctwork:

FlexibleDuctwork:

LightweightDuctwork:Material:

Fire Dampers:

Volume ControlDampers:

Automatic ControlDampers:

Non-ReturnDampers:

Access Openingsand Inspection

Covers:Grilles andRegisters:

Diffusers:

DisplacementVentilators:

Hoods:

ExternalLouvres:

Roof Cowls:

CatalogueNo. or Ref.

IdentificationRef.

Materials

October 1997 Schedule No. 2—Page 1 1 of 36NOTE: If more than one 'page 1 1 ' is used, they are to be numbered 1 1 A, 1 1 B , etc


Section 8—Ductwork, Dampers and TerminalDevices (cont'd)Volume Control Dampers:

Type


Type

Section 8—Ductwork, Dampers and TerminalDevicesAutomatic Control Dampers:



IdentificationRef.

Materials CatalogueNo. or Ref.

IdentificationRef.

Materials


Section 8—Ductwork, Dampers and TerminalDevices (cont'd)Non-return Dampers:

Type

October 1997 Schedule No. 2—Page 13 of 36NOTE: If more than one 'page 13' is used, they are to be numbered 13B, etc

Section 8—Ductwork, Dampers and TerminalDevicesInspection covers:


IdentificationRef.

Materials Type CatalogueNo. or Ref.

IdentificationRef.

Materials


Section 8—Ductwork, Dampers and TerminalDevices (cont'd)Grilles:

Type


Section 8—Ductwork, Dampers and TerminalDevicesDiffusers:


IdentificationRef.


IdentificationRef.

Materials


Section 8—Ductwork, Dampers and TerminalDevicesDisplacement ventilators:

Type


Section 8—Ductwork, Dampers and TerminalDevices (cont'd)Hoods:


IdentificationRef.


IdentificationRef.

Materials

Specification 037 Schedule No. 2 Contract No._Air conditioning, air cooling andmechanical ventilation for buildings

Section 8—Ductwork, Dampers and TerminalDevicesExternal louvres:

Type


Section 8—Ductwork, Dampers and TerminalDevicesRoof cowls:


IdentificationRef.


IdentificationRef.

Materials


Section 9—Air Control including Induction, Terminal Reheat and VAV Units

Induction Units:Manufacturer(s):

Country of Origin:

Variations from Specification:

Catalogue Identification Frequency Band (Hz) 125 250 500 1000 2000 4000 8000No. or Ref. Ref

Sound Power Level(dB)at 1m

Section 9—Air Control including Induction, Terminal Reheat and VAV Units (cont'd)

Single and Dual Duct Terminal Devices:Manufacturer(s):

Country of Origin:


Catalogue Identification Frequency Band (Hz) 125 250 500 1000 2000 4000 8000No. or Ref. Ref ———————————————————————————————————————————————


October 1997 Schedule No. 2—Page 17 of 36NOTE: If more than one 17' is used, they are to be numbered 17A, etc



Variable Air Volume (VAV) Units:Manufacturer(s):

Country of Origin:


Catalogue Identification Frequency Band (Hz) 125 250 500 1000 2000 4000 8000No. or Ref. Ref

Sound Power Level(dB) at 1m


Fan-assisted VAV Terminals:Manufacturer(s):

Country of Origin:


Catalogue Identifi- Frequency Band (Hz) 125 250 500 1000 2000 4000 8000 FanNo. or cation ————————————————————————————————————————————— motor

Ref Ref Sound Power Level(dB) at 1m

October 1997 Schedule No. 2—Page 18 of 36NOTE: If more than one 'page 18 ' is used, they are to be numbered 18A, 18B, etc



Underfloor Fan-assisted VAV Terminals:Manufacturer(s):

Country of Origin:


Catalogue Identifi- Frequency Band (Hz) 125 250 500 1000 2000 4000 8000No. or cation

Ref. Ref


Constant Volume Flow Regulators:Manufacturer(s):

Country of Origin:





Fanmotor(kW)


IdentificationRef

Frequency Band (Hz) 125 250 500 1000 2000 4000 8000


Section 10—Fan Coil Units

Manufacturer(s):

Country of Origin:(All details to be for fan speed proposed for duties)


Identification Type Cat NoRef or Ref

Heat Cool Vol kW Current 125 250 500 1000 2000 4000 8000(kW) (kW) m3/s ————————

Start (A) FLC (A)

Output Fan Sound Power Level (dB) at 1mFrequency Band (Hz)


Section 11—Ventilating Ceilings, Platform Floors, Kitchen Ventilation Ceilings, Chilled Ceilings andChilled Beams

Ventilating Ceilings:

Manufacturer:Country of OriginType(s) of TileMaterial(s)Suspension System(s)Degree of AccessFire Rating DetailsAcoustic Performance

Platform Floors:Manufacturer:Country of OriginType(s) of TileMaterial(s)Pedestal TypeFire Rating DetailsAcoustic PerformanceAir Terminal DetailsAir Terminal ConnectionsMethod and Arrangement for Earthing

October 1997 Schedule No. 2—Page 21 of 36NOTE: If more than one 'page 2V is used, they are to be numbered 21 A, 21B, etc


Section 11—Ventilating Ceilings, Platform Floors, Kitchen Ventilation Ceilings, Chilled Ceilings andChilled Beams (cont'd)

Kitchen Extract Ceilings:Manufacturer:Country of OriginMaterial(s)Suspension DetailsAccess ProvisionsCleaning MethodNon-active SectionsLocal HoodsTotal Area m2

Perforated AreaAir Flow m3/hFire Performance

Chilled Ceilings:

Manufacturer:Country of OriginMaterial(s)Suspension DetailsAccess ProvisionsTotal Area m2

Active Area m2

Minimum Surface TemperatureMaximum Cooling CapacityPipe Connections Sizes Main/BranchFire Performance

Chilled Beams:

Manufacturer:Country of Origin

Material(s)Tube:Fins:Casing:

Suspension SystemMinimum Surface Temperature



Section 12—In-Room Air Conditioning Units

Manufacturer:

Country of Origin:

Compressor

Type kW Current PF Ph Frequency Band (Hz) 125 250 500 1000 2000 4000 8000

Start FLC(A) (A)

October 1997 Schedule No. 2—Page 23 of 36NOTE: If more than one 'page 23' Is used, they are to be numbered 23A, 23B, etc

Identification Type Catalogue Output FanRef No or Ref ———————————— ——————————————————

Heat Cool Vol kW Current PF(kW) (kW) m3/s ——————————

Start (A) FLC (A)

Heating Coolingmedium medium



Section 12—In-Room Air Conditioning Units (cont'd)

Unitary Reverse Cycle Heat Pumps

Manufacturer:

Country of Origin:

Identification Type Catalogue Output Fan Heating CoolingRef No or Ref ———————————— —————————————————— medium medium

Heat Cool Vol kW Current PF(kW) (kW) m3/s ——————————

Start (A) FLC (A)

Compressor

Type kW Current PF Ph Frequency Band (Hz) 125 250 500 1000 2000 4000 8000

Start FLC(A) (A)



Specification 037 Schedule No. 2 Contract No.____Air conditioning, air cooling andmechanical ventilation for buildings

Section 13—Water Pumps

Identification Manufacturer Type & Drive Duty MotorRef and Country of ———————— ———————————————————————————

Origin Flow Head kW Starter Current PF Ph(l/s) (kPa) type

Start (A) FLC (A)



Section 14—Pipework

Flexible Piping End Connections:Manufacturer:Country of Origin:Type:

Section 15—Valves, Cocks and Strainers

Valves:Manufacturer(s):Country of Origin:Variations from Specification:

Cocks:Manufacturer(s):Country of Origin:Variations from Specification:

Strainers:Manufacturer(s):Country of Origin:Variations from Specification


Flexible Connectors:Manufacturer:Country of Origin:Type(s):

Expansion Devices:Manufacturer:Country of Origin:Type(s):

Air Vents:Manufacturer:Country of Origin:Type(s):

Self-sealing Test Points:Manufacturer:Country of Origin:Type(s):



Section 16—Water Storage Vessels

Identification Manufacturer and Type CapacityRef Country of Origin (l-actual)

Dimensions (mm)L H W

ManufacturingStandard

Pressure TestRating (bar)

Section 17—Thermal Insulation

Material Application Manufacturer Country of Origin



Section 18—Water Treatment

Specialist Manufacturer/Supplier:

Country of Origin:

System Treatment Proposals:

Corrosion Control Scale/Deposit Control Microbiological Control

Water Treatment Plant:Manufacturer:Model No:Rated Capacity:

Chemical Conditioning Equipment:Manufacturer:Mixing Tank Capacity:Method of Dosing and Bleed-off:

Water Meter:Manufacturer:Model No:

Water Test Kits:Manufacturer:Model No:

Corrosion Monitoring Rig:Manufacturer:Model No:




Section 19—Heat Wheels, Heat Pipes, Air and Water Plate Heat Exchangers and Run-around Coils

Country of Origin:Heat Wheels:Manufacturer:

IdentificationRef.

Capacity

Volume

Supply Exh.(m3/s) (m3/s)

Energyrecovery

(GJ)

Carry-over Efficiency (%)(%max)

max averageannual

Dimensions (mm)

H W

Motor Pressure drop (Pa)

kW Ph Start (A) FLC (A) Starter type Normal speed Min. speed Supply duct Exhaust duct



Section 19—Heat Wheels, Heat Pipes, Air and Water Plate Heat Exchangers and Run-around Coils(cont'd)

Heat Pipes:

Manufacturer:

IdentificationRef.

Capacity

Volume

Supply(m3/s)

Exh.(m3/s)

Carry-over

(%max)Energy

recovery(GJ)

Country of Origin:

Efficiency (%) Dimensions (mm)

max average L H Wannual

Pressure drop(Pa)

Supply Exhaustduct duct

Section 19—Heat Wheels, Heat Pipes, Air and Water Plate Heat Exchangers and Run-around Coils(cont'd)

Plate Heat Exchangers/Run-around Coils:

Manufacturer: Country of Origin:

Identification Flow rates Energy Pressure dropRef. —————————————— recovery ———————————————

Primary Secondary /GJ) Efficiency (%) Dimensions (mm) Primary side Secondary side

Air Water Air Water max average L H W Air Water Air Waterm3/s l/s m3/s l/s annual (Pa) (kPa) (Pa) (kPa)

October 1997 Schedule No. 2—Page 30 of 36NOTE: If more than one 'page 30' is used, they are to be numbered 30A, SOB, etc


Section 20—Belt Drives, Variable Speed Drives and Guards

Type of drive Plant ref No.s Manufacturer Country of Origin Cat. No.

Belt and pulleys

Fluid Coupling

Electro-magneticinduction(eddy current)

Switched ReluctanceMotors

Inverter drivers

Section 21—Vibration Isolation and Noise Insulation

Anti-vibration Mountings:Manufacturer: Country of Origin:

Identification Ref Type Catalogue No. or Ref. Isolation Efficiency (%)

October 1997 Schedule No. 2—Page 31 of 36NOTE: If more than one 'page 31 ' is used, they are to be numbered 31 A, 31 B, etc


Section 21—Vibration Isolation and Noise Insulation (cont'd)

Silencers:Manufacturer: Country of Origin:

Identification Type Cat No. Generated Noise and Dynamic Insertion Loss (dB) PressureRef or Ref ———————————————————————————————————— Loss (Pa)

125 250 500 1000 2000 4000 8000 Hz

Section 21—Vibration Isolation and Noise Insulation (cont'd)

Acoustic Enclosures:Manufacturer: Country of Origin:

Identification Type Cat No Generated Insertion Attenuation (dB)Ref or Ref Noise Loss (dB) ——————————————————————————————

125 250 500 1000 2000 4000 8000 Hz



Section 22—Instruments

Pressure Gauges (steam)Manufacturer:Country of Origin:Gauge type(s):Gauge scale range(s):Gauge accuracy:

Pressure Gauges (water)Manufacturer:Country of Origin:Gauge type(s):Gauge scale range(s):Gauge accuracy:

Pressure Gauges (air)Manufacturer:Country of Origin:Gauge type(s):Gauge scale range(s):Gauge accuracy:

Filter Differential Pressure GaugesManufacturer:Country of Origin:Gauge type(s):Gauge scale range(s):Gauge accuracy:

ThermometersManufacturer:Country of Origin:Thermometer type(s):Thermometer scale range(s):Thermometer accuracy

Section 23—Automatic Controls

Manufacturer:Country of Origin:Systemi) Pneumatic:ii) Electric/Electronics:Range(s) of equipment offered:

Automatic Control Damper ActuatorsManufacturer: .......Country of Origin: .......

Automatic Control Valve ActuatorsManufacturer:Country of Origin:

October 1997 Schedule No. 33 of 36NOTE: If more than one 'page 33' is used, they are to be numbered 33A, 33B, etc


Section 24—Starter and Control PanelsManufacturer(s): ..................Country of Origin: ..................

i) Panels:ii) Starters:

Identification Ref Type Dimensions (mm) No. of sections for transport

H W

Section 25—Electrical Equipment and Wiring

Equipment Manufacturer(s): .............................Country of Origin: .............................Installing Contractor(s): .............................

Method of preventing interference to automatic control systems:



Section 26—Inspection, Testing and CommissioningRefer to description of specific requirements within particular section.

Commissioning Specialist:

Name:

Address:

Section 27—Maintenance and Operation Procedures and Documents

Refer to description of specific requirements within particular section.



Summary of Schedule No. 2

The total number ofpages submitted forSchedule No. 2 is:

Signed (as in Tender offer):

Name:

Position:

for and on behalf of:

Address:



If you have comments on this document please fill in a photocopy of this form and send it to DEO (Works).Please do not use the shaded areas of the form.

Originator: Date:

Reference:

Section/Clause/Sub-clause or Annex/Paragraph N° Page N°s:

Change Detail:

Continuation Sheet included ? YD

Reason:

Continuation Sheet included ? YD

Printed in the United Kingdom for The Stationery OfficeJ0030876 5/98 C12 10170

October 1997 159