BA 72/03 - Standards for Highways€¦ · may 2003 design manual for roads and bridges volume 3 highway structures: inspection and maintenance section 2 maintenance part 3 ba 72/03

May 2003

DESIGN MANUAL FOR ROADS AND BRIDGES

VOLUME 3 HIGHWAY STRUCTURES:INSPECTION ANDMAINTENANCE

SECTION 2 MAINTENANCE

PART 3

BA 72/03

MAINTENANCE OF ROAD TUNNELS

SUMMARY

This Advice Note provides guidance on proceduressuitable for the maintenance of road tunnels locatedwithin Motorways and Other Trunk Roads. It coversgeneral aspects of organisation and detailed aspects oftunnel inspection, servicing and cleaning for the tunnelstructure and its equipment. It complements therequirements of BD78 (DMRB 2.2.9): Design of RoadTunnels.

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BA 72/03

Maintenance of Road Tunnels

Summary: This Advice Note provides guidance on procedures suitable for the maintenanceof road tunnels located within Motorways and Other Trunk Roads. It coversgeneral aspects of organisation and detailed aspects of tunnel inspection,servicing and cleaning for the tunnel structure and its equipment. It complementsthe requirements of BD78 (DMRB 2.2.9): Design of Road Tunnels.


THE HIGHWAYS AGENCY

SCOTTISH EXECUTIVE DEVELOPMENT DEPARTMENT

WELSH ASSEMBLY GOVERNMENTLLYWODRAETH CYNULLIAD CYMRU

THE DEPARTMENT FOR REGIONAL DEVELOPMENTNORTHERN IRELAND

Volume 3 Section 2Part 3 BA 72/03

May 2003

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VOLUME 3 HIGHWAY STRUCTURES:INSPECTION ANDMAINTENANCE

SECTION 2 MAINTENANCE

PART 3

BA 72/03

MAINTENANCE OF ROAD TUNNELS

Contents

Chapter

1. Introduction

2. Roles and Responsibilities

3. Organisation and Management of Maintenance

4. Inspection and Servicing Categories

5. Tunnel Structure Cleaning

6. Structure Maintenance

7. Ventilation System

8. Lighting Systems

9. Drainage Equipment

10. Fire Safety Equipment

11. Communication and Traffic Controls Equipment

12. Plant Monitoring and Control or EnvironmentalControl System

13. Electrical Power

14. Emergency Power Equipment

15. Service Building and Plant Room Maintenance

16. References and Glossary of Terms

17. Enquiries

Appendix A Typical Staff Structure and Profile

Appendix B Guidance on Safety DuringMaintenance Works and Inspections

Appendix C Guidance on Health And SafetyLegislation

Appendix D Examples of Detailed MaintenanceSchedules for Lighting and Ventilation

Appendix E Typical Tunnel Closure Schedule

Appendix F Guidance On Emergency Exercises


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Chapter 1Introduction

1. INTRODUCTION

General

1.1 This document provides essential guidance forthe maintenance of Motorway and other Trunk Roadtunnels. It is intended as a tool for developing the mostappropriate and sustainable maintenance approach toany road tunnel.

1.2 It complements the requirements of BD78/99(DMRB 2.2.9): Design of Road Tunnels. The adviceregarding cleaning and maintenance frequencies in thisdocument is based upon more up-to-date information. Itsupersedes advice given in Figure 14.1 of BD78/99. Inpractice, for a particular tunnel, such frequencies mayneed to be reviewed based on changes to traffic levelsand seasonal variations actually experienced.

1.3 Aspects of the document will be of particularinterest to the following parties during the variousstages of a tunnel’s life.

i. The Tunnel Design and Safety ConsultationGroup (TDSCG) and the Design Organisation(DO) during the planning and design of a new orrefurbished road tunnel.

ii. The Managing Agent (MA) and TunnelOperating Authority (TOA) responsible, orplanning to take responsibility, for a road tunnel.

iii. Specialised contractors, equipmentmanufacturers and others involved in tunnelmaintenance.

Scope of Document

1.4 The document covers general aspects oforganisation and management of maintenance; detailedaspects of tunnel cleaning, washing, inspection,servicing and testing of equipment, structure and otherelements of road tunnels. It includes for emergencymaintenance works.

1.5 It has been written with particular reference toHighways Agency documentation and maintenancepractices. Other Overseeing Organisations should beconsulted about its application to the maintenance ofroad tunnels for which they have responsibility.

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1.6 Guidance on typical maintenance arrangementsfor use by the TDSCG and DO during the planning anddesign of a new or refurbished tunnel is included. Thesearrangements will be expressed in maintenancestandards and set down in the tunnel documentation,covering operation, maintenance, inspection andemergency procedures. The provision of appropriatelevels of equipment, operating and maintenancearrangements and tunnel design are closelyinterdependent. Determining the optimum combinationrequires consideration of whole life costs and levels ofrisk.

1.7 Indicative advice, such as the frequency andnature of maintenance inspections etc, is provided.Such advice is intended as an initial aid to thedevelopment of the most appropriate maintenanceprocedures to suit the tunnel concerned. Advicecontained in tunnel specific documentation should takeprecedence, but should be reviewed in operation (seeChapter 3).

1.8 The document may be used as the basis forreviewing and improving current maintenancearrangements.

Information Sources

1.9 An overview of tunnel maintenance andoperation is given in “Operation and Maintenance ofRoad Tunnels” (Ford RJ 1998).

1.10 Information on the general and specific designand operational requirements for road tunnels, togetherwith details of tunnel maintenance and operationaldocumentation normally provided by the designer, maybe found in BD78 (DMRB 2.2.9).

1.11 Much of the detailed technical specificationrequirements for road tunnel equipment may be foundin the Standard Performance Specifications forMechanical and Electrical Installations in RoadTunnels, Movable Bridges and Bridge Access Gantries(MCHW 5.7.2). A separate specification document toadvise on the specific civil engineering requirements ofroad tunnel construction and maintenance is currentlyunder preparation.

1.12 Meetings of the UK Road Tunnel Operators’Forum, organised by the Highways Agency, take place

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Chapter 1Introduction

every six months. They provide a platform for thesharing of ideas and experiences and a valuable sourceof information and feedback on matters concerningdesign, operation and maintenance of UK road tunnels.In addition the forum enables attendees to participate inand benefit from international research and bestpractice work, particularly from the World RoadAssociation (PIARC) Tunnel Working Groups.

1.13 Information on general procedures, specificaspects of routine highway maintenance andmanagement of health and safety are provided in theHighways Agency Trunk Road Maintenance Manual -1999 (TRMM). Volume 2 of TRMM is in the process ofbeing revised to contain performance criteria for tunnelmaintenance.

1.14 Standard procedures for inspection and recordsfor road tunnels are set out in BD53 (DMRB 3.1.6).

1.15 Additional sources of information are referred toin the text and listed in Chapter 16.

Reference to British Standards and Legislation

1.16 Any reference to a British Standard can be takento include any other International Standard or NationalStandard of another Member State of the EuropeanCommunities, which is comparable in its scope andsafety requirements to the given British Standard.

1.17 This document is not intended as a legal manualand any references made to legislation are intendedonly as an indication of the possible legal requirements.Reference should be made to the latest relevant UK andEEC legislation, ISO, BS or other EC Member States’Standards and relevant Department of the Environment,Transport and the Regions’ documents. Tolled tunnelsunder estuaries may be controlled by special legislationsuch as the Dartford-Thurrock Crossing Act 1988.

Definitions

1.18 The Overseeing Organisation is defined in BD53(DMRB 3.1.6).

1.19 The Design Organisation (DO) is defined inBD78 (DMRB 2.2.9).

1.20 The Tunnel Design and Safety ConsultationsGroup (TDSCG) is defined in BD78 (DMRB 2.2.9).

1.21 The Managing Agent (MA) has replaced the roleof the Maintaining Agent. The MA is defined in BD53(DMRB 3.1.6).

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1.22 The Tunnel Operating Authority (TOA) isdefined in BD78 (DMRB 2.2.9) and is the bodyresponsible for the operation, inspection andmaintenance of the tunnel, together with the necessarymaintenance plant and equipment.

1.23 The Term Maintenance Contractor (TMC) is thecontractor appointed by the Overseeing Organisation tocarry out all maintenance work under supervision bythe MA.

1.24 The Managing Agent Contractor (MAC) is thecontractor appointed by the Overseeing Organisationwith the combined roles of the MA and TMC.

1.25 The Highways agency Value for Money Manual(VFMM) is a document providing guidance aimed atachieving better value for money in highwayprocurement and maintenance.

Implementation

1.26 This document should be used forthwith on allschemes for the maintenance of tunnels on trunk roads,including motorways currently being prepared,provided that, in the opinion of the OverseeingOrganisation this would not result in significantadditional expense or delay progress. MAs shouldconfirm its application to particular schemes with theOverseeing Organisation.

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Chapter 2Roles and Responsibilities

ILITIES
2. ROLES AND RESPONSIB
General

2.1 This Chapter summarises the main roles andresponsibilities of the various stakeholders in thedelivery of safe and effective tunnel maintenance. Seealso BD78 (DMRB 2.2.9)

Overseeing Organisation

2.2 The Overseeing Organisation is responsible for:

i. ensuring that a TDSCG is established during theplanning and design of a new or refurbishedtunnel, and agreeing its terms of reference;

ii. overseeing the maintenance of the tunnel throughthe appointment of competent experienced MAsand TMCS with adequate funding and otherresources.

Tunnel Design and Safety Consultation Group(TDSCG)

2.3 The TDSCG should comprise appropriate levelsof representation from the Overseeing Organisation,DO, Police or other control authority, emergencyservices and the MA. It is responsible for:

i. clarifying the design requirements;

ii. agreeing standards of safety, quality andeconomy;

iii. confirming basic operation, maintenance andemergency procedures.

Design Organisation (DO)

2.4 The DO is, in consultation with the TDSCG,responsible for:

i. the procedures for tunnel commissioning,acceptance inspection and handover;

ii. preparing all tunnel documentation needed forthe effective handover of the tunnel to the TOAas described in BD53 (DMRB 3.1.6), BD78

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(DMRB 2.2.9) and MCH 1349.

2.5 Note that in the case of mechanical and electrical(M&E) plant and systems, much of the detailed designsmay be carried out by the manufacturer who mayspecify particular future maintenance and operationalrequirements. See BD78 (DMRB 2.2.9).

Managing Agent (MA), Tunnel Operating Authority(TOA)

2.6 The MA is responsible for:

i. establishing the TOA (or carrying out thisfunction within its own organisation);

ii. implementing a maintenance agreement with theTMC;

iii. overseeing tunnel maintenance to standardsnormally established in service level agreementsand tunnel documentation. Developing,implementing and periodically reviewingmaintenance strategies to meet these standards.See BD78 (DMRB 2.2.9);

iv. all tunnel operations;

v. providing advice and assistance to the police andother emergency services. See BD78 (DMRB2.2.9).

2.7 Senior operating staff of the prospective MA/TOA should be appointed early in the mobilisationprocess and should participate in the TDSCG andVFMM procedures. All aspects of future maintenance,including funding and organisation, should beaddressed during the planning and design stages of anew or refurbished tunnel. Key decisions affectingmaintenance should be approved by the OverseeingOrganisation.

2.8 The MA/TOA is required to:

i. prepare briefs and agree budgets for routinemaintenance works with OverseeingOrganisation;

ii. prepare and prioritise as necessary, detailedrecommendations for proposed remedial,refurbishment or contingency expenditure;

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Chapter 2Roles and Responsibilties

iii. liaise with the Overseeing Organisation on futurework programmes, preparing contracts,supervising works, etc as required;

iv. instruct, monitor and supervise the work of theTMC, checking that competent and suitablytrained personnel are used at all times;

v. undertake regular inspections and surveys, inaccordance with HA standards, and takeappropriate urgent action if anything which posesan immediate safety threat to road users orpersonnel involved in the maintenance andoperation of the tunnel is discovered;

vi. carry out regular comprehensive exercises andrisk assessment to identify and manage allpossible hazards of tunnel maintenance andoperation. Thereafter develop and/or maintain,through agreement with OverseeingOrganisation, TMC and the emergency services,appropriate contingency arrangements;

vii. liaise with emergency services regarding regulardrills and exercises, and ensure they are familiarwith tunnel equipment and its operation. SeeAppendix F for guidance on emergencyexercises;

viii. ensure a complete and up to date set of tunneldocumentation, including the Health and Safetyfile, emergency procedures, operating manuals,etc is available at all times;

vix. keep records of all tunnel maintenance proposals,reports, activities, certificates, etc;

x. notify the Health and Safety Executive ofrelevant safety delegations and appointments andcorrespond as necessary to comply withRegulations (see Chapter 3);

xi. maintain effective and regular communicationswith emergency services, ensuring all partieshave up to date information, relevant telephonecontact numbers, etc;

xii. undertake training of staff to ensure their safetyand levels of competency. For appropriate staff,this should include maintaining currency withbest international practice, developments andthinking through attending UK Road TunnelOperation Forums, etc;

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xiii. co-ordinate with contractors responsible for themaintenance of the motorway communicationssystem provisions within the tunnel.

In England

2.9 The National Motorway Communications Systemis maintained by the Regional Maintenance Contractor(RMC). The Contracts are managed by the RegionalMaintenance Contracts – Management Consultants.

2.10 The National Transmission System is maintainedby the National Maintenance Contractor and managedcentrally by the Highways Agency.

In Scotland

2.11 The communication and transmission system isthe National Driver Information Control System(NADICS), which is maintained by a term maintenancecontractor under the management of the NADICSSystem Operator.

In Wales

2.12 The combined communication and transmissionsystem is maintained by the Regional MaintenanceContractor. The contracts are managed by the TrunkRoad Agent or the Regional Maintenance Contracts –Management Consultants.

In Northern Ireland

2.13 Presently there are no tunnels in NorthernIreland.

Term Maintenance Contractor (TMC)

2.14 The TMC is responsible for:

i. undertaking maintenance works, as instructed bythe MA/TOA, using its resources or specialistsubcontractors;

ii. holding and keeping up to date all documentationand records relevant to routine and minormaintenance;

iii. setting up and carrying out effective and safeprocedures for the routine maintenance of alltunnel features and equipment in accordance withthe HA standards (or as instructed otherwise bythe MA/TOA to reflect current best practice);

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Chapter 2Roles and Responsibilities

iv. reporting urgently any defects or circumstancesthat threaten the safety of tunnel users orpersonnel;

v. responding efficiently and effectively to reportsfor assistance in dealing with tunnel incidents,including fire and spillages;

vi. undertaking emergency exercises as required bythe MA/TOA or emergency services;

vii. training of staff to ensure their safety and levelsof competency. For appropriate staff, this shouldinclude maintaining currency with bestinternational practice, developments and thinkingthrough attending UK Road Tunnel OperationForums, etc.

Managing Agent Contractor (MAC)

2.15 The roles and responsibilities of the MAC arethose of the MA, TMC and TOA.

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Chapter 3Organisation and Management of Maintenance

NAGEMENT OF
3. ORGANISATION AND MAMAINTENANCE
General

3.1 The objective of tunnel maintenance is to sustainthe tunnel assets in a safe and usable condition, whilstobtaining best value for money. Such maintenanceshould also promote the safety of the travelling publicand personnel, avoid traffic delays, and minimise anyadverse environmental impacts.

3.2 This chapter explores the organisation of theTOA and the framework and tools necessary to managetunnel maintenance effectively.

Organisation of TOA

3.3 Good organisation of the TOA, normally a part ofthe MA, is essential to achieving effective maintenancethrough a considered strategic approach. Senioroperational and maintenance staff should ideally beappointed at an early stage in the design of a newtunnel, and definitely well in advance of taking over anexisting tunnel. The appointments should be structuredto cover the spectrum of management, technical andoperational skills needed and to provide effectivecommunications with the other stakeholders.

3.4 In planning the staff and resources necessary formaintenance, account should be taken of any otherfunctions that may be carried out by the TOA, such asroutine traffic management and emergency response.Tunnel staff employed by the TOA may carry dualresponsibility for normal operations and emergencyconditions. Appropriately trained and qualified staffshould be designated specific responsibilities in thecase of emergencies. See BD78 (DMRB 2.2.9).

3.5 All staff involved in tunnel maintenance shouldhave the necessary qualifications, knowledge andexperience to effectively carry out their duties andresponsibilities. Staff should not be assigned to dutiesunless they have received the necessary training andhave been formally assessed for competence to serve inthe post. A continuous training programme, includingrefresher courses, should ensure staff areknowledgeable in all aspects of the engineering systemsin use. Records should be kept of the training receivedby staff and the reviews undertaken to identify the needfor such training and its suitability.

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3.6 The TOA organisation will depend on theindividual tunnel and whether it is manned orunmanned. Two broad categories of tunnel operationare defined in BD78 (DMRB 2.2.9):

i. manned tunnels have their own dedicatedmanagement structure and resources that takeresponsibility for traffic surveillance and the safeoperation of the tunnel, including response toincidents and emergencies. The structure mayinclude for dedicated maintenance staff;

ii. unmanned tunnels are designed to operate asfully automatic facilities and do not havepermanent operating and monitoring staff at thetunnel. However, there needs to be a rapidresponse in the event of equipment failure orother emergencies. Responsibility for initiatingaction in connection with tunnel equipment inunmanned tunnels varies and will depend on anyagreements and arrangements with the trafficpolice.

3.7 An example of a tunnel maintenance organisationfor a non-tolled road tunnel, with planned maintenanceundertaken through term contracts, is shown inAppendix A. This also provides guidance on the generalbackground and training required for personnel. Themain difference for a tolled tunnel will be the staffemployed in collecting tolls on a shift basis and thosedealing with accounting for the cash collected, tollprepayments, welfare and security.

3.8 Whether the tunnel is manned or not, TOA staffshould ensure emergency cover is provided on a24-hour basis, within a schedule of response times, tocarry out or oversee all maintenance work (includingthat contracted out). See BD78 (DMRB 2.2.9).

3.9 Sometimes the operation of a road tunnel iscarried out on a shared responsibility basis. Normallythe Local Highway Authority will have responsibilityfor all work in connection with the roads and theirmaintenance and the Overseeing Organisation will haveresponsibility for the tunnel structure and its equipment.See BD78 (DMRB 2.2.9).

3.10 Where the TOA is part of a larger MA, staff maybe available who are also assigned to other duties

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within the MA. Common services for administration,design, contract preparation, health and safety, legaladvice, plant and testing facilities may also exist.

3.11 A single member of staff should be appointed asSafety Officer see BD78 (DMRB 2.2.9). Furtherrequirements regarding aspects of safety are alsocovered in BD78 (DMRB 2.2.9). Staff should include,where necessary, those with qualifications andauthorisation to comply with statutory safetyprocedures such as ‘Permit to Work’ systems relating tohigh voltage equipment and confined spaces.

Quality Plan

3.12 The MA/TOA will be Quality Assuranceaccredited (to BS EN ISO 9002) and have developedand submitted a Quality Plan for approval by theOverseeing Organisation as part of the tenderingprocess for the term commission. It will contain amanagement strategy that sets clear and sustainableperformance objectives, delegates responsibility andestablishes lines of communication.

3.13 A Quality Plan will identify the key objectivesunder the commission and how these will be managedto best effect. It will, for example, explain how:

i. project briefs will be established/clarified andperiodically reviewed and communicated;

ii. appropriate resources and tools will be identified,allocated and managed and suppliers will beassessed and approved for use;

iii. audit trails will be generated and made readilyaccessible through a controlled filing andarchiving system;

iv. the training and development needs of staff willbe identified and delivered.

3.14 Regular meetings between the OverseeingOrganisation MA/TOA should be held to review theQuality Plan and renew the key objectives.

Main Maintenance Objective

3.15 The MA/TOA must establish the maintenanceobjectives to be managed. The following objectives arelikely to apply to all tunnels:

i. sustaining tunnel assets in a safe and useablecondition;

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i. obtaining value for money through a whole lifecost approach;

ii. ensuring safety to road users and staff;

v. minimising disruption to traffic through carefullyplanned maintenance operations;

. minimising environmental impacts.

onstraints

.16 The framework has to be developed withinarious constraints (see below). In the case of a new orefurbished tunnel, the Overseeing Organisation/DOill have developed maintenance standards within

onstraints of legislation, financial rules of theverseeing Organisation and local circumstances of the

ndividual tunnel. The maintenance standards becomedditional constraints within which the TOA will thenurther develop the maintenance strategy.

egal Framework

.17 The legal framework is derived from primaryegislation (Acts), secondary legislation (eg Orders oregulations), European legislation and common law.

.18 TRMM Volume 3 contains the followinguidance on Health and Safety that is relevant to tunnelaintenance:

. a list of health and safety legislation, codes ofpractice and guidance notes, with briefexplanatory notes;

i. identification of workplace hazards withincompounds. This is of direct relevance to tunneloperators’ compounds and workshops, and itsprinciples may be applied to hazards in controlrooms, service buildings and in the tunnel;

ii. application of Construction (Design andManagement) Regulations 1994 to highwaymaintenance. The regulations apply to themajority of tunnel maintenance activities,according to regulations 2(1)a and 2(1)e.However some activities may not be notifiable.Where not specified in the contract, adviceshould be sought from the OverseeingOrganisation in designating the ‘client’ underthese regulations. Its regulations include theappointment of a planning supervisor andprincipal contractor, provision of information,preparation of a health and safety plan,

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assessment of competence, allocation ofresources and the completion and maintenance ofa health and safety file.

3.19 The TOA should establish a set of procedures andworking practices based on risk assessment techniques(eg Ford, 2000) and other methods used to ensure theseregulatory provisions are enacted.

3.20 Further guidance on safety is contained in BD78(DMRB 2.2.9) and summarised in Appendices B and C.

3.21 Atkinson (1997) lists a summary of otherlegislation commonly encountered in highwaymaintenance. The following Acts are of particularrelevance to tunnel maintenance:

i. Local Government, Planning and Land Act(1980);

ii. Highways Act (1980);

iii. Road Traffic Regulations Act (1984);

iv. New Roads and Street Works Act (1991).

3.22 In Scotland, the equivalent legislation for (i.) and(ii.), namely The Town and Country Planning(Scotland) Act 1997 and The Roads (Scotland) Act1984 respectively, apply.

Maintenance Funding

3.23 Maintenance costs are greatly influenced bydecisions made during the design process, particularlythe type and quality of equipment to be used and itsexpected life in service. Full involvement of the MA forsuch decisions at TDSCG meetings is important. Anoverview on the reduction of operational costs is givenin (Ford, 1999).

3.24 Funding of future maintenance for new orrefurbished tunnels should be addressed during theplanning stages and be based on:

i. a 5-year programme for all tunnel assets;

ii. a 10-year replacement programme for assets witha design life of 10 years or less.

3.25 For an operational tunnel the TOA shoulddevelop a business plan for maintenance and maketimely submissions of bids linked to the inspectioncycle, BD53 (DMRB 3.1.6) to secure the necessaryallocation of funds for all anticipated costs. Thebusiness plan should identify what is to be achieved, the

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reasons, alternative options and risks considered,method, timing and quality. Included in the plan shouldbe suitable funding allocations for emergencies,contingencies and capital replacement. Guidance forMAs on obtaining funding and the bid cycle iscontained in Area Management Memos 22, 23 and 24.

3.26 The TOA should work within agreed financialrules and follow agreed procedures for purchasing,tendering and auditing. When the TOA is part of a localgovernment body these rules are drawn from the LocalGovernment Act (1972), and interpreted into standinginstructions and procedures by the Local Authority.

3.27 Costs in the business plan may be grouped underthe following headings:

i. staffing;

ii. planned maintenance;

iii. emergency maintenance or contingency;

iv. overheads such as vehicles, buildings etc;

v. capital replacement.

3.28 Expenditure and future liabilities should beprojected over a 3-year rolling bid cycle withmanagement accounts that allow a continuousassessment of spend set against projected budgets.

Local Constraints

3.29 Local constraints influence the nature, timing andfrequency of planned tunnel maintenance activities. Theprimary local constraint is the demand to keep thetunnel open to traffic as much as possible. Plannedclosure must avoid periods of peak day, holiday andlocal event traffic. Therefore closures tend to be limitedto periods of low traffic flows, for example late eveningthrough to early morning and/or during weekends.

3.30 Closures are normally required to be agreed withthe Overseeing Organisation in advance. Other localbodies affected by the closure will need to be consultedand the public provided with adequate warning andalternative routeing, if necessary. The notice requiredwill depend on the planned duration of the closure andsuitability of alternative routes.

3.31 Considerable pre-planning and prioritising isrequired to achieve the maximum amount ofmaintenance work per closure. Allowance needs to bemade for set-up times, contingencies, and safety checksbefore re-opening.

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Tools for Management of Maintenance

3.32 There are a number of tools to facilitate themanagement of maintenance against set objectives,including those discussed below:

Maintenance Standards

3.33 Maintenance standards will be expressed withinservice level agreements and tunnel documentation.They should be developed in consultation with theTDSCG and the prospective TOA (see also BD78(DMRB 2.2.9)) and will specify standards ofperformance to be maintained.

3.34 Maintenance activities should be consistent with,and not compromise, the basic design assumptions ofthe tunnel as listed in BD78 (DMRB 2.2.9) and thetunnel documentation.

3.35 Maintenance standards and codes of practiceshould be reviewed at intervals of not less than 3 yearsto coincide with Principal Inspections, with additionalreviews when specific circumstances require this.

Maintenance Strategy

3.36 The delivery of effective maintenance over thelifetime of the tunnel requires a maintenance strategy.This should reflect the requirements and/orrecommendations of the following:

i. Tunnel O&M Manual and historic maintenancerecords;

ii. Highway Maintenance Handbook (Atkinson,1997). This also includes a section on tunnelmaintenance;

iii. TRMM Volumes 1, 2 and 3;

iv. Highway Maintenance. A Code of Good Practice(Association of County Councils, 1989).

3.37 Essentially there are three types of maintenance:

i. planned preventative maintenance;

ii. unplanned or reactive maintenance, such asbreakdown and fault repair;

iii. pre-planned ad hoc major repairs, replacementsand/or improvements.

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3.38 The tunnel maintenance strategy should strive toavoid unplanned tunnel closures through prudentpreventative maintenance and optimise on tunnelclosures. For example, increasing intervals of serviceand part replacement would reduce the cost of plannedmaintenance and the numbers of planned tunnelclosures. However, this would also normally result inincreased frequency of faults and breakdowns, with aconsequent decrease in safety levels for users, increasein costs of contractor call-out, and increase indisruption due to unplanned tunnel closures.

Tunnel Documentation and Maintenance Records

3.39 Tunnel documentation and maintenance recordsare of critical importance to safe operation andmaintenance. Retaining test records, up-to-datemanuals, record drawings etc are essential requirementsfor safe operation and effective maintenance.

3.40 Original tunnel documentation, coveringoperation, maintenance, inspection and emergencyprocedures, will normally have been developed by theDO in consultation with the TDSCG. Requirements fordocumentation and typical contents of suchdocumentation are listed in BD 78 (DMRB 2.2.9). TheDesigner will, in accordance with the requirements ofthe standard performance specifications (MCHW5.7.2), write specific manuals for the operation andmaintenance of plant and equipment with detailssupplied by the manufacturers.

3.41 Records provide information on pastperformance upon which future decisions may be made,evidence that acceptable standards are achieved andinformation for future costing. In many cases, keepingadequate records is a statutory requirement andrepresents verification of compliance with legalobligations for testing and maintenance. As explained inthe TRMM Volume 2, Part 1, records are necessary todeal with claims arising out of any alleged defect.Making a nil return is also important as it provides apositive record.

3.42 Records will be generated by different parts ofthe operations and maintenance organisation, as well asexternal contractors and consultants, and otherassociated organisations. Procedures should bedeveloped to ensure that information is readily andeasily accessible. This should include co-ordinating theoutput from computer-based fault reporting systems,hand-written logs, video logging, voice recording etc, aswell as reports compiled by contractors at the end ofmaintenance activities and engineers investigating andmonitoring the fixed assets of the tunnel.

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3.43 Management procedures should ensure thatrecords are retained in an appropriate archive for anappropriate period and that they remain secure,accessible and retrievable. The records managementsystems should be part of the Quality ManagementSystem for the operation and maintenance of the tunnel.

3.44 The records management system should becapable of analysing the records collected and reportingsummaries of the information at appropriate levels ofdetail. Statistical, logistical and financial analysis of therecords should be undertaken to enable the performanceof engineering assets to be assessed. On a schemespecific basis, they may indicate significant trends inperformance, which may be related to changes inoperational and maintenance strategies, or they mayidentify the potential for, and timing of, equipmentfailures.

3.45 Summary records for individual tunnels shouldbe submitted in accordance with BD53 (DMRB 3.1.6)for national collation, as part of the information forfurther research needs, future policy reviews,benchmarking and value for money exercises.

Knowledge of Tunnel Asset Base Requirements

3.46 The TOA should have detailed knowledge of therequirements to maintain the asset base including thefollowing:

i. corrective/emergency maintenance assessmentand maintenance requirements;

ii. routine/planned maintenance requirements;

iii. knowledge of failure modes and effects on anasset (FMEA);

iv. appropriate holding of spares and consumables tosupport an asset throughout its expected life;

v. maintenance logistics to support each asset.

Determining and Reviewing MaintenanceRecommendations

3.47 The equipment manufacturers’ recommendationsmay be taken as a starting point for schedulingequipment maintenance in tunnel documentation. Theseare normally specified as time intervals based onmaximum duty, but commonly actual use may be less.For example, fans in tunnels with uni-directional trafficmay be used only occasionally. Conversely, the tunnelenvironment may be more aggressive and corrosivethan is often assumed by manufacturers, which may act

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to shorten the life of equipment. Before varying therequirements in tunnel documentation, an appropriatelyqualified operator should gather operationalinformation based on the past performance of eachsystem and analyse this using engineering judgement.The reasons for any variations to the maintenanceschedules should be recorded and the effects of changemonitored and reviewed.

3.48 As an example, the application of alternativepolicies in respect of tunnel lamp changing is illustratedin Chapter 8. Zuman (1997) discusses policies fordealing with street lighting - these principles may beapplied to other equipment. However, Zuman notes thatchoice may be governed by technical, financial andpolitical factors, and therefore judgement is required onthe part of the TOA.

Asset Management Software

3.49 Proprietary facility management computerprograms are available that generate maintenanceschedules, check lists, task sheets and automaticwarnings of tasks required. The computer programstend to be of a generic nature and will require someconfiguration to meet tunnel specific needs. Most arecapable of dynamic trend analysis and reporting, as wella range of other functions that assist in fast andeffective facility management.

3.50 Alternatively, adaptation of proprietaryspreadsheet or database applications may provesufficient, but they will be more user-driven.Spreadsheets are effectively two-dimensional (flat file)databases and are relatively easy to use. Relationaldatabases are more demanding to set up but have awider capability. Both may be configured to provide alevel of functionality that greatly assists facilitymanagement.

3.51 Some modern applications may be configured topassively receive and analyse data direct from thetunnel’s plant monitoring and control system.

3.52 Hand held data capture devices are used forhighway maintenance. They may be adapted forgenerating lists that require checking off (including nilreturns). They may also be used in conjunction with barcodes on tunnel walls and inside equipment boxes toidentify equipment and confirm that the correctequipment has been examined. Data from these or othersimilar portable devices may be transferred to acentralised facilities management system.

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3.53 All electronic data should be in a conventionalformat that can be readily converted for futureapplications without data loss.

Risk Assessment

3.54 Risk analysis and management should beregarded as an integral part of tunnel operation andmaintenance. The Management of Safety at WorkRegulations of 1992: HSC Approved Code of Practice1992 (revised 1999/2000) requires risk analyses to beregularly carried out and to include for the safety of thepublic and those nearby. The risk analysis processinvolves identifying hazards, assessment of theirlikelihood of occurrence and their consequences, andultimately their management. This should involveidentifying, evaluating and reviewing the options forreducing risk. Guidance on Risk Assessment at Work:Health and Safety: European Commission, 1996provides useful general information.

3.55 For straightforward task based applications, riskassessment may involve a team review, followed by thesetting up of a risk register based on a simple risk-ratingmatrix (eg Ford, 2000). For more complex tasks, riskassessment may involve setting up a workshop of allinterested parties (police, emergency services etc) toidentify and assess (eg Ford, 2000) a full range ofhazards affecting the operation. Use of computer-basedrisk modelling techniques may be required for decisionson managing the more critical hazards. PIARC/OECDare to make available software for quantitative riskanalysis and decision support for the passage primarilyof dangerous goods transport through tunnels,(http://www.aipcr.lcpc.fr/index.html, andhttp://www.oecd.org). The software can be used equallywell for non-dangerous goods transport.

Maintenance Planning and Schedules

3.56 Maintenance schedules should be developedfrom the information contained in tunneldocumentation, notably manufacturers’recommendations. Taken together these requirementsform the basis of the planned maintenance activitiesthroughout each year.

3.57 It is essential that the planned maintenanceworkload is evenly distributed throughout the year tomake the best use of, and minimise, tunnel closures.This should reduce disruption to traffic and the costsassociated with each tunnel closure.

3.58 A rolling programme may be used to distribute
work. For example, if lamps are to be changed at
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intervals of one year, and four tunnel closures arescheduled each year, then one quarter of the lightsmight be replaced during each closure. A rollingprogramme has the additional benefit that peaks ofequipment failure may be avoided.

3.59 Planning of maintenance tasks may beconstrained by factors such as the availability of accesstime, physical access limitations, proximity workinglimitations etc. Planned maintenance carried out intunnel service buildings may be scheduled outside thetunnel closure programme but should still be includedinto the overall maintenance schedule. Examples ofmaintenance schedules and a typical tunnel closureprogramme are shown in Appendices D and E.

3.60 Before each tunnel closure, the maintenanceschedules, any necessary but unplanned maintenanceworks and the availability of spares and consumablesshould be reviewed at a meeting of all parties involved.Any necessary deviations from traffic managementplans should be identified. The safety implications ofthe programmed maintenance and traffic managementworks should be reviewed and any new hazardsidentified and subjected to a risk assessment. Suchmeetings should be recorded and the minutes shouldform part of the activity record.

3.61 On completion of the tunnel closure, themaintenance activities should be reviewed in a similarmanner. Any faults or incipient problems not rectifiedshould be recorded and scheduled for future action.Relevant historical data should be collated (see BD53(DMRB 3.1.6)) and analysed for planned maintenanceimprovements.

Forms of Contract

3.62 Planned maintenance of assets often ‘peaks’ atregular intervals. The TOA should consider whether tocope with these ‘peaks’ of activity by using contractors.This will be influenced by the availability of specialisedmaintenance personnel and organisations.

3.63 “First line” maintenance or breakdownmaintenance may best be provided by a dedicatedresource employed by the TOA. This would beavailable on a 24-hour basis to provide assistance foremergencies and other incidents and may help tomaintain engineering standards.

3.64 For new equipment, the manufacturer or installermay provide effective “second line” maintenance cover.This cover may only be available under the terms of the12 month defect liability period or a separate contract.

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3.65 The choice of contractor may be restricted fortechnical reasons. For example, maintenance ofproprietary software may only be possible by the codesupplier, or only limited numbers of contractors mayhave the necessary expertise or equipment formaintenance.

Service Level Agreements

3.66 Service level agreements are an effective tool formanaging the delivery of service to achieve specificstandards of performance. Such agreements seek toguarantee the availability of appropriate resources andtimely delivery of a quality service.

3.67 The TOA will operate under a service levelagreement with the MA/Overseeing Organisation. Inaddition the TOA will implement, usually through theTMC, service level agreements with maintenancesuppliers to, for example, categorise call-out responsetimes in the event of equipment failures and to put inplace tools, equipment and spares to facilitateimmediate rectification. Service level agreements willalso apply to routine maintenance activities such astunnel washing, equipment calibration, etc.

Works Instructions Manual

3.68 A works instruction manual is used to clearlydefine the procedures to be followed in theimplementation of the maintenance strategy and otherworks within the tunnel confines. These procedures areprepared by the MA/TOA for the implementation ofcurrent best practice and for fulfilling their legal andcontractual obligations.

3.69 Such procedures should, for example, provide therobust and effective approach to the management ofsafety as required by CDM Regulations. During typicaltunnel maintenance activities the tunnel would bedefined as a temporary site, in accordance with theTemporary Sites Directive.

Condition Assessment and Prioritisation

3.70 The programme of inspections and servicingshould identify the routine maintenance, repair andrenewal required, to enable efficient programming ofthe work and to make timely application for funds.

3.71 It is good practice in preventative maintenance tocarry out visual inspection and simple testing whereconvenient during routine maintenance. For exampletesting of insulation resistance may reveal deteriorationdue to overheating or contamination and enable

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remedial action to be taken on a planned basis beforecomplete failure occurs.

3.72 Defects that are identified as a result ofinspections or servicing should be categorised forpriority. Prompt attention should be given to defectsthat present an immediate or imminent risk. If there is arisk of short-term deterioration, procedures foremergency maintenance should be followed. Otherdefects should be assigned priority for repair withinplanned programmes of work.

3.73 Prioritisation is strongly linked to risk analysis,safety considerations and value engineering, as well asfunding constraints. Some guidance is given inAtkinson (1997).

Value for Money

3.74 In order to achieve quality and value for money,the procedures in the VFMM should be followed duringthe planning and design stages of new tunnels andmajor capital maintenance. The implications andprovision for operation and maintenance should be fullyconsidered in relation to capital works at eachBenchmarking, Value Management, Estimating, RiskAnalysis and Value Engineering review stage.Consideration of whole life cost is an important part ofthis process.

3.75 The TOA of an existing tunnel should also followthe procedures in the VFMM. Further information onthe application of Value Management and ValueEngineering principles, respectively, in the context ofroad tunnels is given in Bird et al (2000) and Evans etal (2000).

Spares and Stock Control

3.76 An adequate, but not excessive, stock of sparesand consumables should be retained to enable the TOAto undertake planned and emergency maintenanceworks. Consideration should be given to rate of stockuse, re-order levels, quantities and lead-time. In order toreduce expenditure and storage space, consistent withoperational requirements, consideration should be givento storage off site, eg parts to be supplied by contractorsor agreements with manufacturers for rapid delivery.However, for older equipment the possibility of sparesno longer being available should be kept under review,and consideration given to increasing the stock ofspares.

3.77 The store should be located close to the tunneland provide a suitable environment to avoid any

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equipment damage or deterioration. This particularlyapplies in the case of computer hardware and electroniccomponents. The store premises should be maintainedsafe and secure in use.

3.78 The store should have a stock control system,preferably computerised, for assessing availability,locating and retrieving stock. Procedures should bedeveloped for inspection, testing and handling ofequipment.

Corrective Maintenance Procedures

3.79 Effective procedures should be developed forcorrecting and recording all potential equipment failureor damage. Procedures should be in place at all times inan operational tunnel, in order that the necessarycorrective or emergency maintenance may beimplemented immediately. Reference should also bemade to TRMM Volume 2, Part 1 regarding generalhighway emergency procedures.

3.80 In developing procedures, risk assessment shouldbe undertaken to assess the potential emergenciestaking into account such factors as:

i. time scale of an emergency from initialassessment to completion of repairs;

ii. the potential effects of equipment failures onsafety and traffic flow though the tunnel;

iii. whether the tunnel can remain operational whilethe fault or failure is rectified;

iv. location of affected equipment, eg roof, trafficspace, pavement, ducts, etc.

3.81 Procedures may vary depending on whether thetunnel is manned or unmanned and the proportion ofmaintenance undertaken by contractors. Indeed,decisions about such arrangements depend on theirsuitability for corrective maintenance. The followinggeneral principles apply.

3.82 Operating staff should have clear guidelines forcall-out of maintenance staff and the action to be takenin the event of faults, eg whether a lane closure or boreclosure is required.

3.83 Faults normally require direct inspection andassessment by maintenance staff available on a 24-hourbasis. Increasingly equipment may have remote controlreset and diagnostic facilities, which enable theoperational and maintenance staff to manage

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emergencies from the tunnel control centre or adjacenttunnel service buildings.

3.84 Guidelines should be in place about necessaryresponse time for each category of defect, eg those thatrequire immediate attention, those that can be left untilthe next working shift or the next routine maintenance.In providing guidelines, the implications of non-availability of equipment and other tunnel assets shouldbe taken into account. For example, the percentage ofoperational fans that is required to meet the designcriteria for ventilation, and numbers of luminaires thatcan fail before the lighting system requires emergencymaintenance. This should minimise the number ofemergency interventions between planned maintenanceactivities.

3.85 Maintenance staff who inspect faults should havea good understanding of all equipment, control systemsand safe working practices so that they might eithereffect simple repairs themselves or rapidly make anaccurate assessment of the need for more extensiverepairs. Access arrangements to equipment should beestablished and tested.

3.86 Spares should be available to suit the requiredrepair response times. They should be certified as fit foruse, particularly after being away for repair.

3.87 Procedures should include recording of faults andrepairs carried out, as well as any fault not repairedimmediately.

Obsolescence

3.88 Equipment may become obsolete when spares areno longer available or improved equipment is availablethat may offer savings in running or maintenance costs.Decisions to replace equipment should be taken afterconsidering future discounted costs of capitalreplacement, running, maintenance and spares.

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Chapter 4Inspection and Servicing Categories

CING CATEGORIES
4. INSPECTION AND SERVI
General

4.1 Categories of inspection and servicing standardsare given in TRMM Volume 2, Part 1 for highways ingeneral and BD53 (DMRB 3.1.6) specifically for roadtunnels. The requirements are discussed below in thecontext of their application to road tunnels. For mosteffective results, each type of inspection should beconducted separately.

Safety Inspections

4.2 Safety Inspections are defined in TRMM Volume2. In road tunnels, they are regular visual inspectionsdesigned to identify defects that are likely to create adanger to the public or staff or lead to unnecessarilyhigh maintenance costs or disruption to traffic. Suchdefects may include:

i. collision damage and debris;

ii. water seepage;

iii. ice formation;

iv. spalling concrete;

v. loose, missing or defective equipment, panels,signals and controls;

vi. oil spill or accumulation of dripped oil and/ordebris posing a fire risk.

4.3 The scope of Safety Inspections will depend onwhether the tunnel is manned or unmanned and whattunnel informational systems exist and how they aremonitored. For all cases, a Safety Inspection from aslow moving vehicle or on foot, as appropriate, shouldbe carried out at intervals determined following riskassessments, but not less often than monthly. Wheremonitoring equipment does not provide completecoverage, it may be necessary to carry out SafetyInspections on a daily basis.

Ad-hoc, Superficial Inspections

4.4 Superficial (“on the surface only”) Inspectionsare defined in BD53 (DMRB 3.1.6) and are ad-hoc,informal inspections for obvious defects. These

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inspections should be carried out as an “ongoingresponsibility” by TOA staff whenever they are at thetunnel. Although informal, keeping basic records ofsuch inspections is recommended (see Chapters 2 and3).

Detailed Inspections

4.5 Detailed Inspections are defined in TRMMVolume 2. They are designed to establish programmesof routine maintenance tasks not requiring urgentexecution and are of particular relevance to highwayitems. Guidance on Detailed Inspections is set out inChapter 6. Specific requirements for inspection mayalso be contained in the tunnel documentation cateringfor tunnel specific needs.

Cleaning, Inspection, Servicing and Testing

4.6 In the case of many items of mechanical andelectrical (M&E) equipment, Detailed Inspections arenot specifically suggested because that objective shouldbe accomplished during routine servicing.

4.7 General guidance on equipment maintenance forthe purpose of planning and review is set out inChapters 5 to 15; but that contained in tunneldocumentation should normally take priority. Eachtunnel has unique conditions of traffic, generalenvironment and equipment level and use. Therefore,the necessary maintenance should be determined in thefirst instance by the designer, taking account ofmanufacturers’ recommendations and the requirementsof the IEE wiring regulations (BS 7671), set out intunnel documentation, and subsequently reviewed inoperation by the TOA (see Chapter 3).

General Inspection

4.8 General Inspections are defined in BD53 (DMRB3.1.6) and comprise a thorough visual inspection ofrepresentative parts of the road tunnel. GeneralInspections of tunnel structures should be carried out atintervals of 2 years. General Inspections of M&Eequipment and a functional check of all emergency andessential systems should be carried out at intervals ofone year. No General Inspection is necessary when aPrincipal Inspection is being carried out.

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Chapter 4Inspection and Servicing Categories

Principal Inspection

4.9 Principal Inspections are defined in BD53(DMRB 3.1.6) and comprise a close and detailedexamination of all accessible parts of the tunnel.Principal Inspections of tunnel structures should becarried out at intervals not exceeding 6 years. PrincipalInspections of M&E equipment and an emergency drillof functions should be carried out at intervals notexceeding 3 years. With the agreement of theOverseeing Organisation these intervals may, inexceptional cases, be extended upwards to a limit of 10years and 5 years respectively. It should be noted thatperiodic inspection and testing of electrical installationsshould also be in accordance with BS 7671, normally atintervals not exceeding five years, and less for certainitems. The TOA should consider the co-ordination ofBS 7671 inspection and testing with PrincipalInspections.

Special Inspections

4.10 Special Inspections are defined in BD53 (DMRB3.1.6) and comprise a close examination of a particulararea or defect of special concern.

May 20034/2


EANING

Chapter 5Tunnel Structure Cleaning

5. TUNNEL STRUCTURE CL

General

5.1 This Chapter provides an overview of thecleaning requirements for the tunnel structure. OtherChapters give cleaning advice for specific items thatshould also be considered when planning tunnel-cleaning operations.

Purpose

5.2 Cleaning of the tunnel structure (including anycladding systems) is principally necessary to maintainthe required level of light reflectance from the tunnelwalls. Maintaining the required reflectance enhancessafety and reduces the energy consumption of thelighting system. Cleaning of the structure may alsoreduce the risk of surface structure and fire damagethrough the removal of corrosive, toxic and flammabledeposits and may offer other operational benefits, forexample to ease inspection and maintenance operations.Additionally maintaining the tunnel structure in a cleancondition creates a favourable and comfortingimpression for the road user.

Frequency

5.3 Surfaces which are required to have a highreflectance (normally the lower, lightly coloured, partof the tunnel walls, especially at the portals) should becleaned sufficiently frequently to ensure that therequired luminance is achieved at all times without theneed for excessive lighting provision. The exactfrequency of cleaning required is tunnel specific andmay depend on a number of factors such as season ofyear, highway gradient, highway geometry, traffic speedand traffic composition. Weather also influencescleaning requirements, for example, a tunnel canbecome very dirty within 24 hours if approach roads aresalted. It may also be influenced by other factors suchas any leakage through and staining of the tunnelstructure.

5.4 The optimum cleaning frequency for a particulartunnel structure should be established by recorded trials(note that different cleaning frequencies may be testedin different parts of a tunnel in order to determine theoptimum frequency). As an indication, it may be helpfulto note that cleaning four times per year is typical forsome tunnels on UK trunk roads.

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5.5 Other parts of the tunnel where high reflectanceis not required (notably the tunnel crown) may becleaned if excessive build up of deposits is observedduring routine inspections. Such deposits may beconsidered excessive if there is a significant risk ofdetritus falling onto the carriageway or if there isconsidered to be a fire hazard, for example if dustbuilds up or if oil is present. Additionally, cleaning ofthese areas may be appropriate if their condition is suchthat personnel or equipment are at risk of significantsoiling during other maintenance works - leading toinefficient maintenance.

5.6 Cleaning requirements for specific items ofequipment may be scheduled separately to generalstructure cleaning and should be described within thespecific maintenance requirements for those items.

Scheduling

5.7 Individual tunnel cleaning operations shouldnormally be scheduled immediately before any other in-tunnel maintenance operations. As such, tunnel cleaningshould usually form the first major activity during amaintenance closure of the tunnel.

5.8 Cleaning should not be carried out if freezingconditions are likely to occur in the tunnel. It should benoted ventilation in damp conditions could causetemperatures to fall below ambient due to latent heatlosses and allowances should be made for thisphenomenon.

Traffic Management and Precautions

5.9 Because of the processes involved, tunnelcleaning will normally take place during a tunnelclosure. Additionally it may be judged prudent toexclude other maintenance personnel from the area inwhich cleaning operations are taking place. This isbecause of the possible hazards arising from lowvisibility and high noise around a jet washing operationand also to avoid unnecessary exposure to anydetergents or other chemicals used in the cleaningprocess.

5.10 Consideration may need to be given to protectingCO, visibility and other sensors, emergency distributionpanels etc from the effects of spray and run-off and tothe isolation of fans.

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Chapter 5Tunnel Structure Cleaning

Processes

5.11 The optimum cleaning process for a tunnelstructure may vary to some extent between tunnelsaccording to the nature of the deposits which should beremoved from the structure. It may also depend on thenature of the structure itself, the lining and fixingmaterials, and in particular, any surface finishes whichhave been used. For example, some types of paint usedin tunnels have been found to be vulnerable to damageby high pressure water jetting. Advice should be soughtfrom the manufacturers of paints and claddings onappropriate cleaning techniques.

5.12 In general, the optimum process will normallyinvolve a combination of pressure washing withdetergents and brushing using vehicle mounted systems.A typical cycle may include a first pass in which avehicle mounted spray bar is used to apply a detergentsolution under pressure to the lining. A second pass,using vehicle mounted rotating brushes may be used toscrub the lining and a third pass with water underpressure to rinse the lining.

Materials

5.13 Optimum choice of detergent may be site specificdue to the differing nature of the deposits to beremoved. COSHH and other relevant regulations shouldbe considered during the selection of materials.Consideration should also be given to any corrosive orother long-term detrimental effect that the cleaningprocess and materials may have on tunnel linings,fittings and equipment. Additionally, detergent choicesare commonly contractor specific and confidential forcommercial reasons.

5.14 It is therefore likely that optimum results may beachieved with a performance specification for tunnelcleaning rather than precise specification of thedetergents and methods to be used.

5.15 Consideration should be given to environmentalissues during selection of detergents or other materialsto be used in tunnel cleaning. Appropriate consentsshould be obtained before any discharges to sewers.

5.16 Consideration should also be given to the healthand safety of the workforce and wherever possiblematerials which present a risk to the workforce shouldbe avoided.

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ANCE

Chapter 6Structure Maintenance

6. STRUCTURE MAINTEN

General

6.1 This Chapter describes routine maintenance,inspection, testing and repairs as applicable to roadtunnel structures.

Tunnel Lining

Description of Typical Structure and AccessArrangements

6.2 The purpose of the tunnel lining is to support thesurrounding ground, exclude ground water and providesupport for any cladding and equipment. The structurallining typically is composed of concrete, that may bereinforced or unreinforced, in situ, sprayed, segmental,or cut and cover tunnels constructed with diaphragm orpiled walls. Items such as steel arches and groundanchors may be built in. Other forms of constructioninclude cast iron or composite steel and concretesegments.

6.3 Access by platform is necessary to the upperparts of tunnel walls and the roof.

Asbestos

6.4 In some tunnels, particularly those withsegmental linings constructed before about 1970,asbestos may have been used in the caulking ropebetween segments. Asbestos cement was sometimesused to form precast air ducting formers. In even oldertunnels, asbestos may have been used for fireproofing.Small concentrations of asbestos dust from vehiclebrake linings etc has been found in dust layers trappedin false ceiling and cladding areas. All these sources ofasbestos may degrade with time, permitting fibres tobecome airborne. This is particularly serious if fibresare present in the ventilation airways and ducts, wherehigher air velocities may disturb fibres more readily.

6.5 Both specialist removal and encapsulation havebeen used to treat asbestos found in older tunnels.Where the presence of asbestos is thought to be apossibility, the advice of the Overseeing Organisationshould be sought without delay. Health and SafetyExecutive, Guidance Note EH40: OccupationalExposure Limits (updated annually) gives guidance.

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Cleaning

6.6 Cleaning of the structural lining should be inaccordance with the guidance given in Chapter 5.

Inspection

6.7 Except at Principal Inspections, inspection willnormally only be possible for exposed parts of thelining. Such areas should be visually inspected as partof the normal structural inspection regime described inChapter 4 and BD53 (DMRB 3.1.6).

6.8 A surface inspection, by an Engineer, should bemade during every scheduled tunnel closure, to identifyany obvious defects with the structural lining. Suchdefects might include collision damage, staining, waterseepage, ice or stalactite formation, joint sealant failure,spalling or cracking. Particular attention should be paidto any defects which have become apparent since theprevious inspection and which do not have an obviouscause.

Routine Maintenance

6.9 Routine maintenance does not include the repairor renewal of structural elements. Such work should beidentified during the regular inspection process, andshould be included in a planned structural maintenanceprogramme.

6.10 Typical routine maintenance requirements, forwhich the maintenance interval should be 12 months,are given below. Additional requirements for complexcomponents should be specified in the tunneldocumentation.

i. remove any remaining graffiti (for best resultsgraffiti should be removed as soon as possible);

ii. clean and rod through any ground water drainagesystem. However, if there is a risk of anunplanned build up of water pressure against thestructural lining, drainage cleaning should bemore frequent;

iii. remove debris from movement joint seals;

iv. repair gap sealant to movement joints;

v. clear any debris from bearing shelves.

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Testing

6.11 Testing is not normally required except wheninstrumentation for long-term structural monitoring hasbeen installed. Such instrumentation should bemonitored in accordance with the requirements of thetunnel documentation. Other testing work, such asultrasonic or ground radar inspection may occasionallybe required but is beyond the scope of this Advice Note.

Tunnel Cladding


6.12 Cladding will normally consist of a panellingsystem and supporting framework of ribs or rails that isattached to the structural lining.

6.13 The purpose of cladding is to provide a smoothsurface for light reflectivity, reduced ventilation flowfriction, and easy cleaning where this is not achieved bythe structural lining. Cladding is also used to improvethe appearance of the tunnel to the user and preventwater leakage appearing on the intrados or damagingoperational equipment and supply cables.

6.14 Access by platform is necessary to the upperparts of tunnel walls and the roof.

Cleaning

6.15 Cladding should be regularly washed to maintainthe required level of luminance within the tunnel duringoperation. The required frequency of washing will besite specific and dependent on operational conditionsand should be determined during the early operationallife of the tunnel as described in Chapter 5.

Inspection

6.16 A surface inspection by an Engineer should bemade during every scheduled tunnel closure to identifyareas of impact damage or other deterioration.

6.17 During every scheduled tunnel closure, thevisible parts of the cladding drainage system should beinspected to identify any blockages, leakages orexcessive accumulation of debris.

6.18 At least once per year, a representative sample ofany exposed fixings should be checked to ensure theirintegrity.

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.19 At the time of every Principal Inspection, a fullyepresentative sample of panel mounting systemlements should be inspected.

outine Maintenance

.20 Any requirements for routine maintenance andepair should be specified in the tunnel documentation.

ortal Structures

escription of Typical Structure and Accessrrangements

.21 Most immersed tube and bored tunnels haveome form of portal structure, usually of a cut-and-over nature, which is distinct from the internal tunneltructure.

.22 Other elements associated with the portal may being-walls, retaining walls, fascias and parapets.ccess by platform may be necessary to the upper partsf portal walls and the roof, however additional accessay be available to carry out inspection to the outside

f the structure whilst the tunnel is operational.

.23 The portal structures may include darkerurrounds, extended fascias and vegetation to assistdaptation of drivers’ eyes to the tunnel interior. Theortal structures may also include daylight screens.

leaning

.24 Cleaning will normally only be necessary on thenside of the portal structure and will normally beimilar to the cleaning applied to the internal tunnelection.

.25 Where the effectiveness of daylight screensepends on cleaning, this should be carried out atntervals determined by experience.

nspection

.26 Inspection procedures should follow those fortructural linings as described above.

.27 Louvres in screens usually have slender ribonstruction and are vulnerable to corrosion and otherorms of surface deterioration.

outine Maintenance

6.28 Routine maintenance does not cover the repair orrenewal of structural elements.

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6.29 Reference should be made to the routinemaintenance requirements for Retaining Walls andBridge Substructures in the TRMM Volume 2.Additional requirements for complex componentsshould be specified in the tunnel documentation.

Testing

6.30 Testing is not normally required.

Structural Concrete

6.31 Concrete structures including tunnel linings,portal structures, suspended road deck slabs and theirsub structures should be inspected and maintained asdescribed in the Design Manual for Roads and Bridges.

6.32 Particular reference should be made to BA35(DMRB 3.3.2) and BD27 (DMRB 2.3.2). However,both documents are under review and in particular thespecification for repairs and related materials has beensuperseded by updated documents used on a schemespecific basis. Improved specifications are available.They will be published as separate documents.

6.33 The inspection of tunnel structures shouldgenerally be carried out in accordance with the BridgeInspection Guide (HMSO 1983). This is currently beingupdated and expanded and will be reissued in the formof a Bridge Inspection Manual, split into six separatevolumes. Volume 1 covering ‘General Procedures’ andVolume 2 dealing with ‘Concrete Bridges and ConcreteElements’ are likely to be most relevant to tunnels.

6.34 These documents describe typical defects to befound in concrete structures and deteriorationmechanisms. They also provide information on thescope and nature of appropriate inspection regimes andtesting requirements.

6.35 Impregnation of concrete by a hydrophobicmaterial inhibits the ingress of water and chloride ions.Advice on the criteria and specification forimpregnation of concrete using a hydrophobic materialsuch as silane is given in BD43 (DMRB 2.4.2) andBA33 (DMRB 2.4.2).

6.36 Advice on painting of concrete is given inBE8/75 (DMRB 2.4.2). This advises that painting isgenerally not recommended, as it presents maintenanceliabilities, may become poor in appearance and causesdifficulties in inspecting any underlying defects in theconcrete substrate. However, where there are specialconsiderations such as on the approach walls and withintunnels, there may be overriding engineering reasons to

May 2003

utilise coatings. Specialist advice will be required whenspecifying and selecting coatings, particularly in termsof reflectance properties and as regards avoiding dirtretention.

6.37 Consideration should be given to developing amanagement strategy for all tunnel structures,embracing inspection, testing, structural assessmentbased on whole life principles, identification of defectsand the determination of the cause of the deteriorationand remedial measures where required.

Waterproofing and Surfacing Deck Slabs

6.38 The need to minimise disruption to traffic mayhave a significant effect on the maintenance of deckslabs in tunnels. Major concrete repairs and the re-waterproofing of existing structures may requireovernight lane closures. If time constraints are severe, itmay be necessary to install preformed replacement deckslabs which have been waterproofed and overlaid with alayer of surfacing (eg Dartford East and West Tunnels).The removal of the existing deck, the positioning ofnew slabs, overlaid with the wearing course and theexpansion joints and bearings may be carried out duringovernight lane closures.

6.39 Deck slabs should normally be waterproofed andsurfaced in accordance with BD47 (DMRB 2.3.4) andBA47 (DMRB 2.3.5).

6.40 When replacement slabs are waterproofed, thedeck waterproofing system or an alternative registeredwaterproofing system should be applied to the end facesto prevent damage, should the expansion joints leak.

6.41 When existing slabs are to be re-waterproofed,sufficient time should be made available to prepare theslabs and complete the installation satisfactorily.

6.42 As much as possible of the old surfacing andwaterproofing system should be removed carefully toprevent damage to the slab. Any material, whichremains on the deck, should be checked to ensure that itis compatible with the new system.

6.43 Testing for chloride damage should be carried outwhere the old waterproofing system has leaked and nearleaking expansion or any other joints to identify the riskof reinforcement corrosion.

6.44 Existing deck slabs may not have an MCHW, U4finish. In such cases, either a surface finish, which issuitable for the waterproofing system, or a

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waterproofing system, which is suitable for the surfacefinish, should be provided.

6.45 Spray or liquid applied systems may be appliedto any sound, void free surface. However, the thicknessof the membrane should be monitored and the effect ofirregularities in the surface on sub-surface drainageshould be assessed. If the thickness of the membrane athigh points is much greater than 2 mm, its flexure underwheel loading may impair the performance of thesurfacing. If water infiltrates the surfacing andaccumulates on the membrane at low points, hydrostaticpressures generated by wheel loading may weaken thesurfacing and its bond to the membrane.

6.46 Spray or liquid applied systems are the mostsuitable for phased construction as there are norestrictions on the width of the installation. Also, sprayapplied systems may be installed more rapidly overlarge areas. However, time must be allowed for curing.

6.47 Noxious fumes may build up in tunnels whenspray or liquid applied systems are being applied andare curing. Therefore, health and safety measures willbe required to prevent asphyxiation and fire hazards.Particular attention should be paid to confined spaces,such as under-deck slabs. Whereas, the build-up offumes may be controlled by ventilation in short tunnels,unnecessary access by site staff and road users shouldbe prevented during application and curing in longtunnels. Any ventilation used during application shouldminimise the local dispersal of the sprayed materials.

6.48 The lowest areas of deck slabs should bewaterproofed first. The installation of the waterproofingsystem should be completed as quickly as possible toprevent contamination of the different layers, butsufficient time should be allowed for materials to cure.Particular care is needed to prevent defects whenmaking overlaps during phased construction. Leakdetection equipment may be used to locate pinholes anddefects at joints or overlaps. Care in detailing joints isrequired and advice from manufacturers of the materialsshould be sought.

6.49 The bituminous mixture directly overlaying thewaterproofing system should be laid and rolled at atemperature which is high enough to achieve a goodbond (eg by activating the tack coat) and to achievesatisfactory compaction, but not so high as to damagethe waterproofing system. The minimum and maximumtemperatures should be obtained from the supplier ofthe waterproofing system and the tack coat supplier.Allowance should be made for the enhanced coolingeffect of any mechanical or natural ventilation.

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6.50 The surfacing in tunnels may be less than the 120mm minimum specified in BD47 (DMRB 2.3.4). Seealso BD78 (DMRB 2.2.9). As the surfacing thickness isreduced, the forces generated by trafficking at theinterface between the surfacing and the waterproofingsystems increase. In such cases proven alternativesshould be considered subject to approval by theOverseeing Organisation.

6.51 The contact area between the mixture directlyoverlaying the waterproofing system and thewaterproofing system itself should be high in order tomaximise the initial bond strength and minimise itsdeterioration in service. Problems are most likely tooccur if the red sand asphalt protection layer that isspecified for bridge decks in BD47 (DMRB 2.3.4) iseither poorly compacted, or omitted so that the mixtureoverlaying the waterproofing system contains largeaggregates and reduces the contact area. In extremecases, mastic asphalt should directly overlay thewaterproofing system, but note that mastic asphaltcomplying with BS 1447: 1988 is unacceptable as thewaterproofing system.

6.52 Generally, the amount of water entering thesurfacing in tunnels will be low if surface water isprevented from flowing along the deck slabs. If this isnot the case, cracks and defects in the wearing courseshould be sealed and adequate falls should be providedto prevent water accumulating on the surfacing. Sub-surface drainage should be provided at low pointswhere water may accumulate within the surfacing at theinterface with the waterproofing system.

6.53 The wearing course should be designedaccording to Clauses 942 or 943 of the Specification forHighways Works (MCHW1). Although surfacing intunnels is not exposed to solar radiation, increasedrutting may occur in tunnels with narrow lanes.

Expansion joints

6.54 Expansion joints with Departmental Registrationshould be installed in accordance with BD33 (DMRB2.3.6) and BA26 (DMRB 2.3.7) to accommodatemovements and rotations at deck ends and provide anacceptable running surface. The number of expansionjoints should be kept to a minimum, to reduce problemsof leakage.

6.55 Measures should be taken to prevent any leakagefrom expansion joints from reaching vulnerable parts ofthe structure by applying protective coatings, andinstalling drainage channels below joints. The need for

May 2003



this will depend on the provision of surface and sub-surface water drainage systems within the tunnel.

6.56 The service lives of expansion joints varyaccording to their type. Further details on the varioustypes available and their advantages and disadvantagesare given in TRL Application Guide 29 (Barnard andCuninghame, 1997). To determine the type mostsuitable for each application, the whole-life cost ofdifferent types should be estimated taking into accounttraffic delay costs.

6.57 Health and safety measures should be taken toprevent the build up of noxious fumes when joints areinstalled.

Expansion Joints and Covers in Immersed TubeTunnels


6.58 Immersed tube tunnels comprise opposing portalstructures linked by immersed preformed tunnelelements. A short closure joint is used to make the finalconnection between the last element to be positionedand the corresponding portal structure or between thetwo last tunnel elements placed.

6.59 Reinforced concrete tunnel elements are oftenmade up of two or more segments, but can be of asingle monolithic unit. Segment jointing systems vary,but usually a continuous loop, grout-injected, water-baris cast into the segments across the match cast joint.This joint is inaccessible and is protected by a dust and/or fire resistant seal (eg fire rope) formed at the internaljoint surface.

6.60 Typically, continuous loop Gina and Omegarubber seals are used at the element joint. The Gina sealforms the initial watertight joint between successiveelements and at the connection to the portal structure.The Omega seal provides a second inner watertightseal, which is mounted once the immersion joint hasbeen dewatered. Both the Gina and Omega seals aredesigned to operate under hydrostatic pressure and toaccommodate thermal movement. A fire resistant steelplate or reinforced concrete infill panel is used toprovide fire protection to the element joint. Concretepanels are provided with fireproof/dust seals and jointfiller material. Some tunnels are fitted with drainagechannels or pipework at the joints to enable inspectionfor leakage and to allow leakage water to be drained.

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6.61 All of the jointing systems are essentially non-replaceable and maintenance free. However, the fireresistant joint covers, fire ropes and/or other forms ofjoint protection may require routine inspection andmaintenance, where they are accessible, ie where notcovered over by ballast concrete, road surfacing etc.

6.62 Access by platform may be necessary to joints inthe upper parts of tunnel walls and roof.

Maintenance

6.63 As the jointing systems are designed to be non-replaceable the dust and fire protection systems arevital to their preservation. There should be no routineneed to remove joint covers, fire ropes etc. Nor do thecovers require specific cleaning or inspections.However, for example, annual service of the jointcovers may include testing of 25% of the screws fortightness and replacement of damaged fixings. Ifdrainage or leakage facilities are provided, inspectionshould be carried out on an annual basis which willrequire removal of the joint cover plates.

Brickwork

Inspection and Testing

6.64 Periodic inspection is necessary to provide anearly indication of problems that may arise. The intervalof the inspection should be based on the current state,condition and the severity of the defect and theprobability and consequences of the defect leading tofailure.

6.65 Much of the data required can be obtained bymeans of visual inspection at touching distance. Othermethods may require a specialist and may include:acoustic emission; radar; hammer tapping; ultrasonicpulse; sonic pulse; thermography; borescope andendoscope; vibration monitoring. It may also benecessary to remove and test sections to determine thestrength. Further information is given in TRL Report204 (Page J, 1996).

6.66 General inspection and loading tests used forarch bridges which may also apply to brickwork intunnels, are given in BD21 (DMRB 3.4.3) and BA16(DMRB 3.4.4).

Repairs

6.67 There are a number of techniques that can beused to repair deteriorating brickwork structures.Further information can be obtained from TRL Report

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204 (Page, 1996) although not all techniques will beappropriate for use in tunnels.

6.68 Repair techniques involving the use of retrofittedor near-surface reinforcement are available forconsideration (Sumon, 1998). Although further researchis required to investigate fully their merits andlimitations, the results seem generally promising andtheir use may be appropriate.

6.69 Local mesh repairs can be carried out to preventsmall areas of loose bricks falling out. This should beconsidered only as a temporary measure untilpermanent work can be undertaken.

6.70 Other short-term improvement measures includethe improvement of drainage to the surrounding fill.This involves the drilling of weep holes through thebrickwork. However, the excess water should be routedto a controlled drainage area and not to another part ofthe tunnel. Special measures may be required if solidsare brought into the tunnel with the drainage water.

Drainage Sump Structures

6.71 One or more sumps will be provided for apumped drainage system where tunnel constructiondoes not facilitate gravity drainage.

6.72 Sumps are normally constructed from reinforcedconcrete and may be located beneath or preferablybeside the carriageway, both within the tunnel and atthe tunnel portals.

6.73 Traffic management may be required for accessdepending on the location of the sump. Since the sumpsare often confined spaces, an access procedure, whichcomplies with the Confined Spaces Regulations, 1997,is necessary.

6.74 Maintenance of pumps, associated equipment andpipework is described in Chapter 9.

Cleaning

6.75 Accumulation of silt and other material in thesumps should be removed at intervals established byexperience. Factors such as the weather (winter saltingon approach roads) and the effectiveness of gully trapsinfluence the rate of accumulation. Specialarrangements may be required after a spillage.

Inspection

6.76 Inspection will normally only be possible forexposed parts of the structure. Such areas should be

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visually inspected as part of the normal structuralinspection regime described in Chapter 4 and BD53(DMRB 3.1.6).

6.77 A surface inspection should be made, duringevery scheduled pumping equipment maintenanceoperation, to identify any accumulation of silt andobvious defects to the sump lining. Such defects mightinclude joint sealant failure, spalling or cracking.

6.78 During Principal Inspections, the sump should beemptied to enable close examination of submergedelements.

Pavement Maintenance

6.79 Reference should be made to the TRMM Volume1 for requirements for pavement maintenance.Assessment includes, as appropriate:

i. High Speed Road Monitor (HRM) surveys;

ii. CHART Surveys on flexible and bituminouspavements;

iii. Visual Condition Surveys (VCS) on concretesurfaced pavements;

iv. Deflectograph Surveys on flexible carriageways,including those with lean concrete roadbases;

v. SCRIM Surveys.

6.80 Inspections, surveys and any maintenance workshould be co-ordinated as fully as possible with othermaintenance activities in the tunnel and adjacent roadnetwork.

Routine Highway Maintenance (Tunnel andApproaches)

General

6.81 Routine highway maintenance of the tunnelcarriageway and its approaches covers such items as:minor carriageway repairs, footways and cycle tracks,covers and gratings, kerbs, highway drainage, gullies,safety fences and barriers, road studs, road markings,and road traffic signs and signals.

6.82 Reference should be made to TRMM Volume 2for guidance on routine maintenance of highway items.The requirements should be followed where applicableexcept as described in the following sections.

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Cleaning

6.83 Gullies should be emptied at intervals establishedby experience. The frequency should be sufficient toensure that solids do not enter the drainage system. Itshould be realised that some tunnels have very shallowgullies. Where the drainage is by pumping, the regularcleaning of the traps is essential to protect the pumpingequipment.

6.84 Portal cross drains require checking and cleaningat intervals determined by experience and theavailability of access.

6.85 General sweeping, cleansing and litter clearingshould be co-ordinated as fully as possible with wallwashing.

6.86 Silt and other solids arising from emptying andcleansing operations pose a potential threat of pollutionand should be disposed of in an appropriate manner,preferably to licensed tips.

Inspection

6.87 Intervals for detailed inspection should be inaccordance with those in the TRMM Volume 2, Table1.1.2 and the Routine Maintenance ManagementSystem (RMMS) User Manual, Tables 3.2.1, 3.2.2 and3.2.3 (Highways Agency, 1996) except where shown inTable 6.1.

6.88 The need for shorter (or longer) intervals shouldbe established by experience, but should not exceed theintervals shown in the TRMM and the RoutineMaintenance Management System (RMMS) UserManual. Shorter inspection intervals than on the generalhighway are considered necessary for some itemsbecause of the particular safety and operationalrequirements of tunnels, including the need toco-ordinate maintenance work with tunnel closures.

6.89 The RMMS User Manual gives guidance onitems to be inspected and defects to be noted, howeversome may not be applicable within a tunnel.

6.90 Inspections should be co-ordinated as fully aspossible with other maintenance activities in the tunneland adjacent road network. For example, considerationshould be given to carrying out inspections beforetunnel closures so that any necessary repairs can becarried out effectively during the closures.

6.91 The running surfaces in tunnels should receiveparticular attention during inspections to check for:

May 2003

i. rutting, which on gradients can prevent fuel spillsentering the gullies and create a fire risk;

ii. lane centre oil drop accumulation, particularly ontunnels with lane control. This creates a skiddinghazard but can be removed by pressure washing;

iii. areas where leakage drips or runs onto thecarriageway. This may give rise to deposits ofleachates, or ice formation in cold weather, whichmay locally reduce skidding resistance.

6.92 Separate drains may be provided to collectground water from behind the tunnel lining or anycladding.

Slope and Ground Stability Adjacent to Portals


6.93 Some tunnels have natural or cutting slopes in thearea adjacent to or above the tunnel portal. Anyinstability of these slopes may pose a threat to the roaduser and to the integrity of the portal zone of the tunnel.

6.94 Stabilisation measures that might be incorporatedin the slopes and ground adjacent to the portals includesurface or sub-surface drainage, ground anchors,soil-nailing or other forms of reinforced soil, cribwalling and planting of vegetation.

Inspection

6.95 A visual or walkover survey of any slopes, whichhave the potential to threaten the tunnel, should beconducted by a competent person at intervals, typicallyof one year, to check for any indications of instability.Normally, the inspection should be conducted in theSpring and, where possible, the inspection should beundertaken by the same individual in successive years,as this will increase the likelihood of changes beingrecognised. Guidance given in HA48 (DMRB 4.1.3)should be followed as appropriate. The collection ofphotographic records of slope condition may also aididentification of changes at future surveys.

6.96 Where evidence of instability or potentialinstability is noted, it may be appropriate to increase themonitoring frequency, or if the risk of slope failureaffecting the tunnel is significant, remedial slopeprotection works should be initiated.

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Routine Maintenance

6.97 Any remedial actions identified as necessary inthe inspection should be undertaken at the earliestopportunity. Typical routine maintenance requirements,for which the maintenance interval should be 12months, are clearing debris from rock traps, drainageditches and filter drains, and repairing rock fences.

Testing

6.98 Periodic monitoring of any instrumentation in theslope (for example piezometers or instrumented rockanchors) should be undertaken as appropriate.

Anchors and Mechanical Supporting Systems


6.99 Anchors, plus fail-safe chains, are used to fixitems, such as jet fans, monitoring equipment and signsto the structure. Mechanical supporting systems areused to support cladding, lighting and cabling systemsand also require fixing to the structure. Failures may befrom corrosion, local structural deterioration, vehiclestrike or vibration. Access, via a platform, will benecessary to inspect and maintain many of these fixingand supporting systems.

Cleaning

6.100 No specific cleaning is required beyond thegeneral cleaning of the structure.

Inspection

6.101 Visual inspection from an elevated level shouldbe carried out at intervals typically of 3 months orduring each tunnel closure, whichever is sooner. Forexample, luminaires are often formed of dissimilarmetal to their supporting system and should be checkedfor galvanic corrosion and other structural deficiencies.

6.102 A detailed inspection of all fixings andsupporting systems should be carried out, from anelevated level where necessary, at intervals typically ofone year, or whenever access is available, whichever issooner.

Testing

6.103 Fixings into the structure should be selected tosurvive their design life without requiring routinestructural integrity testing. Mechanical supporting

sspets

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i

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ystems and fixings should be periodically tested forupport strength and fixation with the structure,articularly where failure represents a safety risk. Forxample, at intervals typically of one year the followingests should be carried out on one-fifth of all items,uch that all items are tested every 5 years:

. torque testing of all screws and fastenings;

i. testing of anchors and their fixity to the structure.This should be done in accordance withmanufacturer’s recommendations, taking care notto exceed the elastic limit of the anchor orsupporting structure;

ii. isolation checks on points vulnerable tobimetallic corrosion;

v. testing of electrical earths.

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Table 6.1 Intervals for Detailed Inspection

Item Suggested intervals (may be varied, but not to exceedthe intervals in RMMS)

Minor Carriageway Repairs 3 months

Footways and Cycle Tracks 3 months

Covers, Gratings, Frames and Boxes 3 months

Kerbs, Edgings and Pre-formed Channels 3 months

Highway Drainage – General Varies

Piped Drainage System At Principal Inspections

Gullies, Catchpits and Interceptors 3 months, co-ordinate with wall cleansing

Motorway Communication Installations Co-ordinate with other communication installations

Embankments and Cuttings See Chapter 6 for slope and ground stability adjacent toportals

Safety Fences and Barriers 1 year

Road Studs 6 months

Road Markings 6 months

Road Traffic Signs Signs lamp failure – as lighting see Chapter 8

Road Traffic Signals – applies to lane control signals Variable message signs – see Chapter 11

Road Lighting See Chapter 8

Cross passage doors 6 months

Outbuildings 12 months

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Chapter 7Ventilation System

7. VENTILATION SYSTEM

General

7.1 This Chapter provides general guidance onmaintenance of ventilation equipment.

Fans for Longitudinal Ventilation

Description of Typical Equipment and AccessArrangements

7.2 BD78 (DMRB 2.2.9) provides descriptions ofvarious forms of ventilation. Forced ventilation, in itsbasic and most common form, is achieved by the use ofjet fans mounted in the tunnel outside of the trafficspace (see Figure 7.1).

7.3 Impeller diameters for jet fans vary notionallyfrom 600 to 1500mm. Fan motor speeds and powerratings vary notionally from 3000 to 750rpm and 5 to60kW respectively, with the larger slow speed fansbeing more efficient and less noisy. Acoustic silencersare fitted to either end of the fans. Most fans aredesigned to ventilate (thrust) in either directionaccording to the selected rotational direction of themotor. Fans are usually fixed in groups (or pods) to thetunnel lining with anti-vibration mountings.

7.4 Jet fans are usually accessed for maintenanceusing hydraulic plant. A full-bore closure is normallyrequired. Specialist, possibly bespoke, handlingequipment and tools are normally needed to install andremove fans. Most procedures will require theapplication of a ‘Permit to Work’ system. Individualfans should be electrically isolated and isolators locked-off using safety padlocks, and warning notices shouldbe posted, where appropriate, before any work iscommenced.

Cleaning

7.5 Typically, the impeller blades and the inside andoutside of the silencers should be cleaned at intervals of3 months.

Inspection

7.6 A visual inspection should be carried out atintervals typically of 3 months.

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7.7 Routine observation through the PlantMonitoring and Control System will highlightequipment failures and may give an indication of thehealth of the fan, for example through changes inwinding temperature and load current readings.

7.8 The bearing life of jet fans tends to be unrelatedto hours run and is, therefore, difficult to predict. Thismay be the result of fans freewheeling with trafficinduced air movement and/or out of tolerance vibrationloads from dirty or unevenly corroded impellers.Vibration monitoring provides an indication of themechanical condition of the fan, including bearings.

Service

7.9 Typically, a service at intervals of 6 monthsshould include the greasing and lubrication of parts.

7.10 At intervals of approximately 5 years, fansshould be removed to the factory for a completeoverhaul including stripping and repainting, and thereplacement of all anti-vibration mountings.

7.11 The maintenance requirements for DOL (directon line) and Star Delta starters are similar to thoserequired for typical electrical distribution and controlequipment, see Chapter 13.

Testing

7.12 At intervals typically of 3 months, the fansshould be run in both directions and checked for unduenoise and vibration. Motor, impeller and blademountings, casing and silencer joint fixings andelectrical terminals should be checked to ensure theyare in good order and tightened or replaced asnecessary. Anti-vibration mounts, safety chain andmovement proximity switches should be similarlychecked and the movement detection system checkedfor functionality.

7.13 At intervals, typically of 12 months, the mainmounting arrangements should be checked andmeasurements made of run and starting current,vibration and insulation resistance. Blade clearanceshould be checked and adjusted if necessary.Measurement of insulation resistance is not essentialbut is a useful diagnostic tool, which may revealdeterioration due to overheating or contamination.

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Fans for Transverse, Semi-transverse and HybridSystems


7.14 BD78 (DMRB 2.2.9) provides descriptions forthe various forms of ventilation.

7.15 Semi-transverse and fully-transverse ventilationsystems require the use of axial, or centrifugal, fansmounted outside the traffic space. The same may betrue for longitudinally ventilated, but the use of jet fansis more common.

7.16 In most case, these fans will be mounted inconnection with supply or extract shafts andaccommodated in a ventilation building accessible by aservice road. Duty and standby arrangements enablefans to be maintained without tunnel closures. Mostmaintenance procedures will require the application ofa ‘Permit to Work’ system.

7.17 In some cases, the airflow direction may bechanged by either reversing the direction of impellerrotation or by reversing the blade pitch angle. Therotational speed of the fans may be varied throughfrequency inversion or a multiple pole motor with stepcontrol. Alternatively, changing the blade pitch anglemay vary the airflow rate.

Cleaning

7.18 Axial etc flow fans should be cleaned at intervalstypically of 3 months.

Inspection

7.19 A visual inspection for damage or deteriorationof axial etc fans and fire dampers should be carried outat intervals typically of 3 months. Where expansionbellows are employed, these should be inspected forsigns of deterioration and for loss of fixity.

Service

7.20 At intervals of approximately 5 years, fansshould be removed to the factory for a completeoverhaul including stripping and repainting. Intervalswill be determined by operational history.

Testing

7.21 At intervals typically of 3 months, the fansshould be run and checked for undue noise andvibration.

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7.22 At intervals typically of 12 months, the bolts inmountings and impellers should be checked andtightened if necessary, the terminals should be checkedand measurements made of run and starting current,vibration, electrical continuity and insulation resistance(also see earlier comment on insulation resistance).Blade clearance should be checked and adjusted ifnecessary.

Fan Handling Equipment

7.23 Jet fans are supported in a cradle system mountedon a trolley. An integral hydraulics scissor liftmechanism provides manoeuvrability when mounting/demounting the fan. A platform lift or other mechanismis required to raise and lower the fan in its cradle asnecessary.

7.24 For some tunnels, duty and standby axial etc fansare permanently fixed, with the nominated standby fanisolated from the air stream by motorised dampers.Such fans may be orientated either horizontally orvertically. In some cases the fans are connected to theductwork using flexible bellows. Lifting equipment isneeded to remove the fans in accordance withinstallation specific safe working procedures.

7.25 Other tunnels have a duty and standby axial fanspair mounted on guided trolley arrangement such thatthe standby fan is displaced from the shaft and therebyexposed for maintenance if needed. Such equipment isof a bespoke design and motorised to enable automaticor manual swapping over of fans as needed.

7.26 Handling equipment is subject to certificationunder statutory law.

7.27 Inspection, maintenance and functional testing ofhandling equipment should be carried out in accordancewith the manufacturer’s recommendations.Maintenance of such equipment introduces safety issuesrequiring system isolation and, in some cases, tunnelclosures. Most procedures will require the applicationof a ‘Permit to Work’ system.

Ductwork and Dampers

7.28 Point extraction of air with a ducted anddistributed supply is common for semi-transversesystems. Fully transverse ventilation requires bothdistributed supply and extraction. Mostly, the ductworkis formed by the tunnel structure, such as the use of aninvert void beneath the road deck in a bored tunnel, forwhich reference should be made to Chapter 6.

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7.29 Fabricated ductwork is often used to connect thefans with the structure, for example the top of aventilation shaft (see Figure 7.2). Although uncommon,ductwork may also be used for forming a distributedextraction system suspended above the traffic space. Inany event, most procedures will require the applicationof a ‘Permit to Work’ system.

7.30 The airflow through the distributed ventilationslots should have been adjusted to achieve an evenlydistributed and balanced flow as part of thecommissioning process. Mechanisms for this are oftenrudimentary, such as baffle plates that partially chokethe air supply slot. Alternatively, adjustable dampersmay have been installed providing for ease and finenessof adjustment. Once set, the flow balance is unlikely tochange significantly.

7.31 Fire dampers may be used to assist in the controlof the fire smoke removal under different modes ofemergency operation and to isolate fans not in serviceenabling maintenance operations to take place.

Cleaning

7.32 The main ventilation ducts, dampers, filters andgrilles require cleaning, particularly the registers inexhaust slots which can become severely restricted bydirt. Intervals should be determined by operationalexperience.

Inspection

7.33 Where dampers are installed, it is normal tocheck their operation (including the fail-safe mode) andlubricate them every 6 months.

Testing

7.34 Supply/extract ductwork systems should betested every 3 years for even flow distribution to/fromthe traffic space. At the same time, flow rates into therespective distributed duct system should be tested.

7.35 The air-tightness of the ductwork system shouldbe regularly tested and maintained as necessary,particularly where the extraction system passes throughpotentially occupied spaces.

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Figure 7.2: Fixed Axial Fans over Supply/Extract Shaft

Figure 7.1: Jet Fans providing Longitudinal Ventilation

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Figure 7.3: Axial Fans on Motorised Duty/Standby Trolley over Supply Shaft

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Chapter 8Lighting Systems

8. LIGHTING SYSTEMS

General

8.1 This Chapter provides general guidance on themaintenance of lighting equipment.

8.2 BD78 (DMRB 2.2.9) includes a section on thedesign of tunnel lighting. “Base lighting” distributedthroughout the tunnel. Brighter “boost lighting” isafforded to the threshold and transitions zones tofacilitate driver eye adjustment on entering and leavingthe tunnel during hours of daylight. Lighting levels areautomatically controlled according to exterior lightlevels.

Base Lighting Luminaires


8.3 Tunnel luminaires are typically fixed to the soffitor to the upper regions of the walls. Maintenance of theluminaires requires an access platform and often aclosure of the bore, as illustrated in Figure 8.1.

8.4 The base lighting luminaires are most commonlyequipped with fluorescent lamps. Switching is normallyprovided to achieve the required changes inillumination levels. Dimming technology is advancingas a viable and improved alternative to traditionalswitching.

8.5 The maintenance of the base lighting luminairesshould be taken to include the luminaires themselves,any dimming system and the immediate supports to theluminaires.

8.6 End-access luminaires have removable end capsthat provide access for maintenance and relamping. Theluminaire must first be lowered, by approximately 200mm, by means of an integral bracket arrangement. It isnot normally necessary to lower the luminaires forroutine cleaning, which can be limited to the outsidesurfaces only.

8.7 Entry to front-access luminaires for maintenanceand re-lamping is by a hinged glass front cover and isgenerally much easier than for the end-accessluminaires.

May 2003

Cleaning

8.8 Typically, the luminaires should be cleaned bywashing and brushing at intervals that depend on therate of dirt accumulation. In most cases, cleaning maymost practically be achieved by the use of manuallabour on a travelling access platform. The cleaninginterval for a particular tunnel should be established byexperience and trials – leaving short sections of lightinguncleaned and assessing the accumulation of dirt.

8.9 The optimum cleaning interval may commonlybe more than the interval between wall washing, butshould not normally exceed the interval required for thehigh pollution category in the TRMM Volume 2, Table1.19.1, namely 12 months for an IP Rating of less than54, and at bulk lamp change for IP 54 or greater.

8.10 Dust from cleaning should be treated as a healthand safety hazard.

Inspection

8.11 Inspections from carriageway level should becarried out when all luminaires are on (normally duringthe day) at intervals of 14 days to detect lamp failures,and an assessment made of the need for repairs, beforethe next scheduled tunnel closure or relamping.Recording of lighting circuit running currents gives anearly indication of lamp failure. In tunnels, it isnormally acceptable for a small proportion of lamps tobe inoperative.

8.12 The use of manual labour on a travelling accessplatform facilitates the immediate identification andrepair of minor defects in the systems, during cleaning.

Relamping

8.13 The intervals for bulk lamp changes provided inthe TRMM Volume 2, Table 1.19.2 should be used forinitial guidance. Information on hours run should beavailable from modern SCADA systems. Trials may becarried out to optimise the intervals, by leaving shortsections of lighting unchanged. It is normally possibleto predict incipient failure because the lights tend toslowly dim rather than suddenly fail.

8.14 During re-lamping, gear-tray equipment shouldbe inspected and tested. The sealing gaskets and clipsshould be replaced, if necessary.

8/1



8.15 Although manufacturers may recommendreplacement at 12 monthly intervals, use of‘tri-phosphor’ tubes for base lighting has been found toincrease this period to 24 months.

Service

8.16 The maintenance requirements for lightingcontrol equipment are similar to those required fortypical electrical distribution and control equipment,see Chapter 13.

Testing

8.17 Tunnel lighting systems are normally designed toaccommodate deterioration in performance of lampswithin their lifetime, together with an allowance forloss of reflectance off tunnel surfaces between cleaning.Therefore, measurement of illuminance would notnormally be recommended unless excessivedeterioration in performance is suspected. If operationalchecks or maintenance records suggest that low or highvoltage may be a cause of malfunctioning of one ormore luminaires, then voltages should be monitoredover a period of time to check whether they are withinthe manufacturer’s guidelines.

Boost Lighting Luminaires


8.18 The boost lighting luminaires provide additionallighting in the entrance and exit zones during daylightand are generally installed in the approximate ratio ofone booster for every two base lighting luminaires.

8.19 Some tunnels may still use low-pressure sodium(SOX) lamps for boost lighting. Newer installationstend to use the higher intensity high-pressure sodium(SON) lamps that are more compact and give a longerlamp life. Typically, switching of groups of luminairesvaries boost lighting levels. Dimming technology forSON lamps is advancing and is expected to improveenergy usage and prolong lamp life.

8.20 Maintenance of the luminaires requires an accessplatform and closure of the bore.

Cleaning

8.21 Boost lighting luminaires should be cleaned atthe same intervals as base lighting luminaires.

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Inspection

8.22 See base lighting luminaires for inspectionprocedures.

Relamping

8.23 The intervals for bulk lamp changes provided inthe TRMM Volume 2, Table 1.19.2 should be used forinitial guidance.

8.24 In the case of the boost lighting, normalexperience is that they run for only around 1000 hours/year and relatively few lamps fail in the intervalsbetween planned maintenance. Also, leaving a fewlamps that fail until the next scheduled maintenancewould not normally impair the overall lightingrequirement. It may, therefore, be appropriate togenerally replace on a breakdown-repair basis only.Thus, the relatively few failures would be replacedduring planned maintenance closures.

8.25 There may be tunnels where “hours run” metersfrom a SCADA system would indicate when lampchange is required. However, lamp life is affected byboth hours run and frequency of switching, whichdepends on the weather, tunnel orientation, and time ofyear. It is therefore difficult to predict, except byexperience, when a luminaire is approaching the end ofits life.

Service

8.26 At intervals typically of 12 months any failedcomponents should be repaired or replaced inaccordance with the manufacturer’s instructions.

Testing

8.27 An operational check, to confirm the variousstages of boost lighting switch on and off, isrecommended typically at intervals of 12 months.

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M


Figure 8. 1: Cleaning the Luminaires

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Chapter 9Drainage Equipment

9. DRAINAGE EQUIPMENT

General

9.1 This Chapter provides general guidance on themaintenance of drainage equipment, such as pipes,pumps and valves. Reference should also be made toChapter 6 for maintenance of sumps and to Chapter 10for maintenance of fire protection systems in sumps.

Pumps, Valves and Pipes


9.2 Pumping systems include: cable chamber pumps,sump pumps, draw-pit pumps, interceptor chamberpumps and the valves and piping which links the systemtogether. Some maintenance operations may requiretraffic management arrangements, depending on thelocations in which access is required.

9.3 Most procedures will require the application of a‘Permit to Work’ system. Since the sumps are normallyconfined spaces then an access procedure, whichcomplies with the Confined Spaces Regulations 1997,is necessary. Removal of pumps commonly requires theuse of a crane or similar lifting equipment.

9.4 Pump duty cycling is usually provided by anelectro-mechanical relay. Sump level monitoringequipment may comprise float switches, or,capacitance, ultrasonic or radio frequency probes.

Inspection

9.5 At intervals typically of 3 months, visualinspection for damage, corrosion, oil levels andcondition, connections and earths should be carried out.

Service

9.6 At intervals typically of 12 months, sump pumpsshould be removed from the sump for limited internalinspection and overhaul. In tunnels where conditionsare particularly onerous, more frequent servicing maybe necessary.

9.7 At intervals typically of 5 years, in accordancewith the manufacturer’s recommendations, sump pumpsshould be removed to the manufacturer’s workshop fora full service and rebuild.

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May 2003

.8 Sump level monitoring equipment should beleaned, checked and lubricated in accordance withanufacturer’s recommendations.

.9 The maintenance requirements for controlquipment and DOL and Star Delta starters are similaro those required for typical electrical distribution andontrol equipment, see Chapter 13.

esting

.10 All aspects of pump operation, including levelontrol, should be tested typically at intervals of 3onths.

.11 Valve operation should be tested at intervalsypically of 3 months, although, to avoid seizure, someanufacturers recommend more frequent operation.

9/1


NT

Chapter 10Fire Safety Equipment

10. FIRE SAFETY EQUIPME

General

10.1 This Chapter provides general guidance onmaintenance of fire safety equipment including cross-bore doors, fire extinguishers, fire hydrants and hoses,fire mains, fire and gas detectors and automatic fireextinguishers or foam flooding systems.

Cross-Bore Doors


10.2 These include doors, door opening mechanisms,emergency exit signs, alarms and beacons associatedwith cross-bore access. A bore closure is required formost operations associated with such equipment.Additionally, if cross-bore doors are operated during asingle bore closure, particular care must be taken toprevent maintenance personnel or materials entering thelive carriageway. Door opening may be detected byautomatic alarms and signalling equipment, thereforeprocedures should be in place for their safe cancellingduring maintenance work.

Cleaning

10.3 All exposed parts should be subjected to thenormal tunnel wall washing processes.

Inspection

10.4 The doors should be inspected and operatedduring every scheduled closure, to identify damage,corrosion or other defects.

Service

10.5 Servicing should include periodic cleaning andlubrication of hinges, handles, bolts and closingmechanisms and remedial painting of doors. If doormechanisms are found to be stiff, due to corrosion anddirt ingress, then replacement with stainless steel partsmay provide a possible solution. The seals ofemergency exit signs should be checked and replaced ifdefective. Lamps, providing illumination for signs,should be replaced at intervals typically of 12 months.

May 2003

Testing

10.6 During every scheduled maintenance closure atest should be carried out to check that alarms andbeacons are visible and audible, to the required level.The doors themselves should open under a reasonablepressure and swing freely through their intended angle.

Fire Extinguishers


10.7 Fire extinguishers are normally housed bothwithin the tunnel service building and in the tunnelemergency panels (See Figure 10.1). The distributionand number of fire extinguishers throughout the tunnelis a function of the tunnel length and geometry. Tosafely remove and replace extinguishers in the tunnel asingle bore closure is normally required.

Cleaning

10.8 The extinguisher should be cleaned as part of theservicing to ensure dials and instructions remainreadable.

Inspection

10.9 The services of a specialised contractor arenormally required. Typically, the distribution, numberand type of extinguishers should be checked at intervalsof 3 months, noting if any have been used or need to berefilled or replaced. If the TOA is aware that anyextinguishers have been used, then they should bereplaced without delay.

Service

10.10 The services of a specialised contractor arenormally required. The typical requirement is servicingat intervals of 12 months, in accordance with therelevant British Standards.

10/1



Fire Hydrants and Hoses


10.11 Figure 10.2 illustrates a fire hydrant and hose reelhoused in a tunnel panel. The distribution and numberof hoses and hydrants throughout the tunnel is afunction of the tunnel length and geometry. A singlebore closure is normally required to safely access firehydrants and hoses in the tunnel.

Cleaning

10.12 Typically, cleaning of the hydrants and hoses isnot required.

Inspection

10.13 A periodic check to see if any hoses are leakingshould be carried out during tunnel closures. Evidenceof significant leakage from fire hydrants or hose pointsshould be investigated at the earliest opportunity.

Service

10.14 Typically no servicing operations are requiredwhich are distinct from routine testing. Periodicreplacement of hoses may be required.

Testing

10.15 Operation of the hydrants, hoses and couplers toverify the delivered pressure should be carried out atintervals typically of 3 months. This may be undertakenby the fire service or by tunnel maintenance staffdepending on local circumstances. The systematic useof fire hoses and hydrants in tunnel cleaning may be anappropriate means of testing the equipment.

10.16 Testing should include: the flushing of hydrantsand operation of the valve to ensure the requiredpressure is achieved with a blanking cap in place; andthe required flow is achieved with the blanking capremoved. This testing, together with any testing ofalarms associated with the hydrants, should be carriedout at intervals typically of 3 months.

Fire Mains


10.17 At least one fire main will be carried within thetunnel. The fire main may be a dedicated service for the

10/2

tunnel or may be a mains water supply also servingthird parties. Various hydrants and isolators may also bedistributed at points along the tunnel. A single boreclosure is normally required to safely access valves inthe tunnel.

10.18 Major maintenance of the fire main, valves andhydrants which require draining of all or significantparts of the system should only be carried out during atunnel closure.

Cleaning

10.19 No cleaning is required other than that needed topermit servicing operations.

Inspection

10.20 Typically at intervals of 3 months, valves shouldbe inspected for signs of leakage. At intervals, typicallyof one year, the main should be inspected for leaks andcracks.

Service and Testing

10.21 Valves should be greased and fully operated tocheck for seizure, or any other problems, at intervalstypically of 3 months. The whole unit should beoverhauled at intervals typically of 5 years: this work isnormally carried out by a contractor and not by the fireservice.

10.22 The operation of pumps, trace heating, pressureswitches etc associated with the fire main should betested at intervals typically of 3 months. Insulation forfrost protection should be inspected and made good asnecessary at intervals typically of 12 months, prior tothe cold weather season.

10.23 Where the fire main also supplies to third parties,testing may cause fine sediment to become disturbed.Water supply companies should be consulted todetermine if flushing would affect supplies to thirdparties. Water mains supply pressure should be testedfor adequacy every 12 months or at times of known lowpressure supply.

10.24 The expansion chamber should be pumped out atintervals typically of one year, when any leaks or cracksshould be repaired, as necessary.

10.25 If it is considered that sections of the fire mainmay need to be replaced or repaired, then a CCTVinspection should be undertaken to determine the extentof any remedial work.

May 2003



Fire Protection (and Gas Detection) Systems


10.26 Selected rooms in tunnel service buildings,enclosed sumps and other hazardous areas are affordedfire protection (see BS 5839: Part 1: 1988) and, whereappropriate, gas detection. Plant room automatic fireextinguishing systems and enclosed-sump foamflooding systems are controlled and monitored throughtheir respective fire control panels. Condition-status andalarms are relayed to the tunnel SCADA system, asappropriate.

10.27 Figure 10.1 shows a typical tunnel panelcontaining nitrogen foam and sump gas-detectionequipment.

10.28 Automatic gas-discharge fire-extinguisher andextraction systems are normally installed in roomswithin the tunnel service buildings that containoperational safety-related equipment, typically the highand low-voltage electrical switchgear, battery, computerand communications equipment rooms. Older systemsmay still use Halon gas, now prohibited from newinstallations. Installations that are more recent may usecarbon dioxide (CO2). The most recent systems usesynthetic gases mixed with nitrogen/argon that, unlikeCO2, are breathable in the concentrations concerned.

10.29 Gas detection systems are sited in locationswhere measurements of gas may be required: eg cablechambers, sumps and draw-pits, tunnel servicebuildings and control and switch rooms. Different gasesmay be measured, typically oxygen and hydrocarbons.The systems trigger events to contain the situation oncea set percentage of the lower explosive limit (LEL) hasbeen passed. Typically pumps are inhibited whenconcentrations reach 30% LEL and then a nitrogenfoam flooding system is initiated. In service buildings,when 20% LEL is reached, alarms and automatic fireextinguishers are triggered and at 30% LEL the gasextraction fan is inhibited.

10.30 A nitrogen-foam flooding system comprises anumber of nitrogen gas cylinders, a foam generating set,a control system and a number of foam-generatornozzles. The foam-generator nozzles are installedwithin the sump and are connected by pipework to thefoam-generating set, normally located in a tunnel panel.A bore closure may be required to safely access thefoam generating set.

May 2003

10.31 Care should be taken to ensure that wholesystems are tested periodically, where for exampleservicing and testing of parts of the system arescheduled at different times or undertaken by differentcontractors.

Maintenance of foam flooding systems

10.32 Maintenance should be in accordance with themanufacturer’s recommendations. Typically at intervalsof 3 months, the panels should be cleaned to ensurereadability and checked to ensure they are clear ofalarms. Checks should also be made for signs ofdeterioration of flexible pipework, and signs ofcorrosion, damage or overheating of all connectors andearths. Nitrogen cylinder pressure should be determinedand all cylinders checked for security.

10.33 A test fire should be carried out together with apurging of foam, in accordance with the manufacturer’srecommendations, at intervals typically of 12 months.Care must be taken to ensure that no one is within oradjacent to the sump when this test is conducted.

Maintenance of gas detectors

10.34 This should be in accordance with themanufacturer’s recommendations. The services of aspecialised contractor are normally required. Typically,the operation of the systems should be tested, electricalconnections checked and the sensors re-calibrated atintervals of 3 months: sensors should be replaced atintervals, typically of 12 months.

Maintenance of automatic fire extinguishers

10.35 Inspection of the automatic gas discharge andextraction system should be carried out at intervalstypically of 3 months. Specialised servicing of thesystem, in accordance with the manufacturer’srecommendations, should be carried out at the sametime, together with testing which may require thecontrol system to be manually overridden.

Maintenance of fire detection systems

10.36 This should be in accordance with themanufacturer’s recommendations.

10.37 Testing and maintenance of the fire alarm anddetection system should be carried out in accordancewith BS 5839: Part 1. This requires daily checks ofpanels and log books and selective system andequipment testing at weekly, 3-monthly, yearly and5-yearly intervals.

10/3


10/4


Figure 10.2: Tunnel Fire Fighting Equipment

Figure 10.1: Tunnel Emergency Panel

May 2003



Figure 10.3: Sump Gas Detection and Nitrogen Foam Flooding System

May 2003 10/5


TRAFFIC CONTROLS

Chapter 11Communication and Traffic Controls Equipment

11. COMMUNICATION ANDEQUIPMENT

General

11.1 This Chapter provides general guidance onmaintenance of any communication cables, telephones,radio systems, closed circuit televisions and variablemessage signs that are not included in the RMC orNMC contracts, see Chapter 2. Reference should alsobe made to Chapter 7 for maintenance of mechanicalsupporting systems.

11.2 In England, maintenance of the NMCS is detailedin the Highways Agency’s Motorway Communications(MC) series of document which take precedence overtunnel documentation. Key documents are listed in theReference Chapter.

Communication Cables


11.3 Communications cables in the tunnel bore, tunnelservice buildings, sumps and drawpits are coveredwithin this Chapter.

Cleaning

11.4 Typically, no cleaning of the cabling is required.Inspections should be carried out on all accessiblecables at intervals typically of 3 months noting anysigns of damage, corrosion or similar defects. Typicallyno routine servicing is required

Telephone Systems


11.5 The provision of telephone systems varies fromone tunnel to another, and historically has beendetermined largely by the requirements of the tunneloperator and the local police and fire service.

11.6 Up to three separate systems may be provided,fulfilling the following functions:

i. an emergency telephone system, to enable thepublic to summon assistance in the event of anincident;

May 2003

ii. a smoke control telephone system, to enable thefire service to communicate between one end ofthe tunnel and the other;

iii. an internal telephone system, for use bymaintenance staff.

Cleaning

11.7 The telephone set should be cleaned at the sameinterval as testing, but is currently carried out monthlyfor the National Network (ref MCH 1743).

Inspection

11.8 Visual inspection for defects and correct numberlabelling should be carried out at the same interval astesting.

Service

11.9 Generally, the telephone systems require noservicing.

Testing

11.10 Typically testing of all aspects of operation of theemergency telephones should be carried out at intervalsof one week, and of other telephones at intervals of 3months. Battery supplies to the telephones should betested at intervals of one year.

Radio-Relay Systems


11.11 A typical tunnel radio-relay system comprises aleaky feeder antenna through each bore of the tunnel,linked to a number of transceivers in a tunnel servicebuilding. For optimum signal quality, the transceiversare normally linked to the appropriate users’ remotebase stations by landlines, so that the tunnel systembehaves as an additional transmitter/receiver on thelocal area communications network.

11.12 In cases where a landline connection from thetunnel service building is not feasible, an externalantenna may be located near the tunnel to receive

11/1



transmissions ‘off-air’ and rebroadcast them inside thetunnel.

Service

11.13 Generally, radio relay systems require noservicing.

Testing

11.14 An on-air test of all channels for acceptablespeech quality should be carried out typically atintervals of one week.

11.15 At typically yearly intervals, the systemfrequency accuracy, transmitted power levels, receiversensitivity and selectivity, and transmitter output andaudio levels to and from the control centre should betested.

Closed Circuit Television Cameras

11.16 Traffic surveillance CCTV cameras are normallylocated on the approaches to and within the tunnel.Cameras may also be used for security surveillance ofother areas such as service building and maintenanceaccess roads. Video images from these cameras areusually accessible in at least one location through amultiplexing system serving an array of monitors withvideo recording provisions.

Cleaning

11.17 Cleaning of the lenses is important to maintainvisibility. The interval will depend on the rate ofsoiling, which will be determined by local traffic andweather conditions.

Inspection and testing

11.18 The equipment is used daily and so any problemsor malfunctions of cameras will be immediatelyapparent. Operation of the pan, tilt and zoommechanisms should be tested at intervals, typically ofone week.

Service

11.19 Servicing of camera and pan, tilt and zoommechanisms and motors depends on the type ofequipment, but typically should be carried out atintervals of 6 months. This may involve removal of thecamera assembly to a workshop. Security of supportsshould be checked, and testing of the CCTV camerafunctions should form part of the servicing programme.

11/2

VMS System


11.20 A typical Variable Message Sign (VMS) systemwill include internally illuminated tunnel signs,internally illuminated post mounted and gantry signs,and a number of different types of rotating prism signs.Each of these different signs has different maintenancerequirements.

11.21 Depending on its location, maintenance orinspection of the VMS may require traffic management.

11.22 There may be a distinction in requirements formaintenance of signs for information and those thathave legal status. The advice in this Chapter is based onthe assumption that all VMSs have legal status.

Cleaning

11.23 Cleaning should be carried out typically atintervals of 3 months depending on the rate of soiling,but should not exceed the one year interval required inthe TRMM Volume 2. Internal cleaning should becarried out at intervals, typically of one year.

Inspection

11.24 A visual inspection of operation and for defectsshould be carried out at an interval that does not exceedthe one month interval required in the TRMM Volume2, Table 1.18.1.

11.25 An internal inspection of the VMSs should becarried out at intervals typically of 3 months.

Service

11.26 The VMS lamps should be replaced within the6-monthly intervals stipulated in TRMM Volume 2 oron reaching 2000 hours of accumulated service life,whichever is shorter.

11.27 Electrical and mechanical components should beserviced at the intervals required in the TRMM Volume2 or in accordance with the manufacturer’srecommendations, whichever is shorter.

Testing

11.28 Testing of all aspects of sign operation should becarried out at intervals not exceeding those required inthe TRMM Volume 2, Table 1.18.1.

May 2003



Traffic Induction Loops


11.29 Traffic Induction Loops comprise a number ofturns of loop cable installed in slots cut into the wearingcourse of the carriageway to form inductive coils whichdetect the presence of a vehicle by its metallic content.

11.30 They are usually fitted on a per lane basis acrossall lanes at a number of sites along a tunnel. Dependingon the loop type they can detect either vehicle presenceor presence and speed. They are linked by loop feedercable to loop detectors mounted in the tunnelmaintenance cabinets.

Cleaning

11.31 The loops require no cleaning.

11.32 The feeder cables should be treated ascommunications cables (see above).

11.33 The loop detectors should be cleaned at the samefrequency as the other equipment within themaintenance cabinets, typically every 12 months.

Inspection

11.34 The loops should be visually inspected wheneverthe carriageway wearing course is inspected, typicallyevery 3 months.

11.35 The feeder cables should be treated ascommunication cables.

11.36 The loop detectors should be inspected whencleaned.

Service

11.37 The loops, associated cables and detectorstypically contain no serviceable components. Service isby replacement on failure.

Testing

11.38 The impedance of the loops should be measuredat least every six months in order to check for hiddendamage to the loop cable.

May 2003

Traffic Computer


11.39 The traffic computer control function typically:

i. looks at vehicle flow, taken from loop detectors,CCTV image analysis etc;

ii. considers environmental factors, such aspollution levels;

iii. sets signs to control vehicle movementsaccordingly.

11.40 The traffic computer may also control tidal flowtraffic signals and maintenance signing for closures.

11.41 A traffic computer does not normally exist as aseparate entity. The traffic control function is usuallyundertaken by the environmental control computer (seesection 12 - Plant Monitoring).

Cleaning and Inspection

11.42 A visual inspection of computers to ensurecooling systems are uninhibited, cleaning filters etc, asnecessary, is required at intervals, typically of 3 months.

11.43 A visual inspection of computer connectionsshould be made at intervals, typically of 3 months.Where appropriate, connection integrity should bechecked.

Service

11.44 Backup copies of software should be stored off-site. Data files, such as system logs, should be copiedon a regular basis. At intervals, typically of 3 months,back up copies of software should be taken.

Testing

11.45 At intervals, typically of 12 months, thefollowing should be tested:

i. power supplies and earthing connections to PLCsshould be tested in accordance with therequirements of BS 7671;

ii. all aspects of computer system operation andresponse;

iii. computer hard discs for bad sector level, capacityand fragmentation.

11/3



Peripheral Units


11.46 Various peripheral units may be interfaced to thetraffic control system, typically these will be additionalinput devices, such as overheight detectors, interfacesto fire systems etc or output devices, such as lanecontrol signals or traffic signals.

Cleaning

11.47 Input devices exposed to the tunnel environmentshould be cleaned at intervals, typically of 3 months.

11.48 Input devices from other systems should becleaned when their host system is cleaned.

11.49 Output devices, ie those presenting visualinfromation to the driver should be cleaned typicallyevery 3 months.

Inspection

11.50 A visual inspection of operation should be carriedout at an interval that does not exceed one month.

Service

11.51 All peripheral equipment should be serviced inaccordance with the manufacture’s requirements and atintervals typically of every 6 months.

Testing

11.52 All peripheral equipment should be tested forcorrect operation typically at intervals of every 3months.

May 200311/4


ND CONTROL ORL SYSTEM

Chapter 12Plant Monitoring and Control or Environmental Control System

12. PLANT MONITORING AENVIRONMENTAL CONTRO

General

12.1 This Chapter provides guidance for maintenanceof the plant monitoring system and maintenance ofcontrol provisions for tunnel lighting and ventilationsuch as carbon monoxide sensors, visibility sensors, airspeed monitors and photometers. Reference should alsobe made to Chapter 6 for maintenance of mechanicalsupporting systems.

Plant Monitoring


12.2 The Environmental Control System (ECS)provides signals to control the tunnel lighting andtunnel ventilation systems. The ECS may also provide ameans of communicating measurements of gas andpollution levels, luminance levels and the status oftunnel systems to a remote location. It is also usual forthe ECS to handle alarms, status information andremote control signals for other tunnel plant,particularly electrical switchgear and emergency andfire protection systems.

12.3 A variety of designs of ECSs may be encounteredin tunnels. Newer designs use a Supervisory Controland Data Acquisition (SCADA) system based on acentral computer with distributed Programmable LogicControllers (PLCs) at each out-station servingequipment. All control and other information is passedalong a common data transmission network. PLCs filterout and direct relevant commands to connectedequipment and relay status information back to theSCADA system. Maintenance procedures depend on theparticular type of system installed.

12.4 The SCADA system itself is often self-diagnosticand does not require planned maintenance.

Cleaning and Inspection

12.5 A visual inspection of computers to ensurecooling systems are uninhibited, cleaning filters etc, asnecessary, is required at intervals, typically of 3 months.

12.6 A visual inspection of computer and PLCconnections should be made at intervals, typically of 3

May 2003

months. Where appropriate, connection integrity shouldbe checked.

Service

12.7 Backup copies of software should be stored off-site. Data files, such as system logs, should be copiedon a regular basis. At intervals, typically of 3 months,back up copies of software should be taken.

Testing

12.8 At intervals, typically of 12 months, thefollowing should be tested:

i. power supplies and earthing connections to PLCsshould be tested in accordance with therequirements of BS 7671;

ii. all aspects of computer system operation andresponse;

iii. computer hard disks for bad sector level, capacityand fragmentation;

iv. local PLC memory batteries.

Carbon Monoxide and Visibility Monitors


12.9 The carbon monoxide and visibility sensors arenormally located at a high level in the tunnel. Aplatform and a bore closure will normally be required toaccess the sensors. Maintenance requirements arespecific to each manufacturer and product.

Cleaning

12.10 Typically, cleaning of the sensors should becarried out at intervals of 3 months.

Inspection

12.11 The equipment is used constantly and so anymalfunctions should become apparent through the ECS.Modern equipment is often fail-safe.

12/1



Service

12.12 The services of a specialist contractor arerequired. Typically servicing and calibration of thesensors are required at intervals of 3 months. It may befound that intervals for calibration may be increased to12 months but the manufacturer’s guidance should besought.

Testing

12.13 Typically at intervals of 3 months, testing ofalarms, alignment and the displays at the ECS terminal,etc should be carried out.

Air Speed Monitor


12.14 Air speed monitoring equipment is normallylocated at a high level in the tunnel. A platform andbore closure will normally be required to access thesensor. Maintenance requirements are specific to eachmanufacturer and product.

Inspection

12.15 The equipment is used constantly so anymalfunctions should become apparent through the ECS.

Service

12.16 The services of a specialist contractor arerequired. Typically servicing is required at intervals of 6months and calibration of the airflow sensor is requiredat intervals of one year. Cleaning and testing normallyforms part of the servicing.

Photometers


12.17 External photometers are generally mounted onpoles (see Figure 12.1) in the verge and central reserveto monitor external light levels. Maintenance may bepossible without a tunnel closure. If works are carriedout during daylight hours, it should be borne in mindthat automatic control levels for the tunnel lighting maybe affected. Photometers may also be mounted insidethe tunnel to compare internal and external lightinglevels.

12/2

Cleaning

12.18 The photometer windows require cleaning,typically at intervals of 3 months, but the interval willdepend on the rate of soiling which will be determinedby local weather and traffic conditions.

Inspection

12.19 The equipment is used constantly and so anymalfunctions should become apparent through the ECS.

12.20 Typically, visual inspection of all connections,electrical earths and the unit itself should be madewhenever the unit is cleaned.

Service

12.21 Washer bottles require refilling with water,cleanser and antifreeze, typically at intervals of 3months. The correct operation and calibration of thephotometer and operation of the wiper and washershould be checked at the same time.

May 2003


M


Figure 12.1: Pole Mounted Photometers

ay 2003 12/3


Chapter 13Electrical Power

13. ELECTRICAL POWER

General

13.1 This Chapter provides general guidance onmaintenance of power cables, earth and lightningprotection systems, high voltage equipment,transformers, low voltage equipment and distributionand control panels. Reference should also be made toChapter 6 for maintenance of mechanical supportingsystems.

Power Cables


13.2 Power cables in the tunnel bore, tunnel servicebuildings, sumps and draw-pits are covered within thisChapter. Some cable pits may be confined spaces andan access procedure, which complies with the ConfinedSpaces Regulations 1997, should be in place. Boreclosures are normally required to access power cableswithin the tunnel.

13.3 Authorised Persons must carry out maintenanceof these items. Such persons must have receivedspecific training on how to operate and work onelectrical systems. Additional training is required forthose working on high voltage systems. Mostprocedures will require the application of a ‘Permit toWork’ system.

Cleaning

13.4 Individual cleaning of the cables is not required.

Inspection editing

13.5 A visual inspection of accessible cables should becarried out at intervals, typically of 3 months.

Service

13.6 Typically, no routine servicing is required.

Testing

13.7 The complete electrical system must be testedperiodically, typically at 5-year intervals, in accordancewith the requirements of BS 7671.

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arthing and Lightning Protection Systems

escription of Typical Equipment and Accessrrangements

3.8 Earthing points are present in various parts of theunnel system, including within the tunnel bore, sumps,unnel service buildings and lightning protectionystem. Bore closures are normally required to accessarthing points within the tunnel.

3.9 Authorised persons who have received specificraining appropriate to work on tunnel electricalystems must carry out maintenance procedures onhese items.

leaning

3.10 Specific cleaning processes are not normallyequired, unless substances likely to cause corrosion areresent.

nspection

3.11 At intervals, typically of 3 months, accessiblearts of the main earthing system should be visuallyhecked for any signs of loose connections or fixings,amage or corrosion.

3.12 Visual inspection of the lightning protectionystem should be carried out in accordance with BS651, normally at intervals of one year. Additionalisual inspections should be made following knownightning strikes.

ervice

3.13 Any faults, corrosion or damage should beepaired immediately.

esting

3.14 The services of a specialised contractor areequired. Resistance to earth of the main earthingystem should be tested in accordance with BS 7671,ypically every 5 years, and of the lightning protectionystem in accordance with BS 6651, typically everyear.

13/1



High Voltage System Circuit Breakers andTransformers


13.15 A typical tunnel will receive two separate 11 kVelectrical feeds. Transformers, usually located in theservice building convert this to the low voltage supplynormally distributed within the tunnel. For oldertunnels, this supply is likely to be at a nominal 415volts; more recent tunnels may use the harmonised levelof 400 volts. High voltage circuit breakers are usuallyprovided with power solenoid operating mechanisms.The closing and tripping supply to each switchboard isderived from dedicated tripping and closing batteryunits, located within the respective HV switch rooms.Mechanical interlocks formed through safety keymechanisms are usually provided within each circuitbreaker to prevent incorrect operation.

13.16 Authorised Persons who have received specifictraining to operate and work on high voltage electricalsystems must carry out maintenance procedures onthese items. Such procedures will require theapplication of a ‘Permit to Work’ system.

Cleaning

13.17 Specific cleaning processes are not normallyrequired.

Inspection

13.18 Inspections of the transformers, typically atintervals of 3 months, should include checks on thefollowing:

i. condition of silica gel breather, which should berenewed if discoloured;

ii. oil level;

iii. confirmation of normal operating temperature.

13.19 In addition, typically at 12-month intervals, cableterminations and oil condition should be checked.

13.20 Corrosion and damage to the transformer shouldbe repaired as necessary.

13.21 Typically, the switchgear should be checked foroverheating or any other readily apparent problems atintervals of 3 months, and a full inspection andoperational check should be conducted at intervals of12 months.

13/2

Service

13.22 Typically, the transformer does not needservicing. The switchgear requires servicing andlubrication at intervals, typically of one year.

Testing

13.23 Operation of the switchgear and indicating lampsshould be tested, typically at intervals of 3 months. Thetransformer oil condition should be analysed, typicallyat intervals of one year. Operation of over-temperatureand over-pressure trippings should be checked every 5years.

Low Voltage System Switchboards and CircuitBreakers


13.24 The switchboards and circuit breakers aregenerally housed in the tunnel service buildings.

13.25 Authorised persons who have received specifictraining appropriate to work on tunnel electricalsystems must carry out maintenance procedures onthese items. Most procedures will require ‘Permit toWork’ procedures

Cleaning

13.26 The circuit breakers and switchgear are usuallyhoused in relatively dust free environments and do notnormally require cleaning. Any such cleaning wouldrequire the application of a “Permit to Work”.

Inspection

13.27 At intervals, typically of 3 months, switchboardsshould be cleaned externally and inspected visually forany obvious damage or signs of malfunctioning. Anti-condensation heaters should be checked. Faultyindicator lamps should be replaced and settings andcorrect installation of protective devices checked.Accessible external wiring connections should bechecked visually for signs of loose connections andoverheating, or other deterioration.

13.28 A visual inspection of cable connections fortightness, cable entries, glands and sleeves for fit anddeterioration and for any other visible damage shouldbe carried out at intervals, typically of 6 months.

May 2003



13.29 Low voltage circuit breakers and relays should beinspected at intervals, typically of 6 months, includingthe condition of the contacts and electrical andmechanical interlocks.

13.30 Main circuit breaker tripping mechanisms, arcshields and contacts should be inspected at intervals,typically of one year.

13.31 It should be noted that cubicles are typicallyinterlocked such that power isolation is required beforethey can be opened. Access to the interior of cubicleswill require the application of a “Permit to Work”.

Service

13.32 Typically, the switchboards and circuit breakersdo not require servicing. Any servicing that becomesrequired should be in accordance with the operation andmaintenance manual.

Testing

13.33 A test of all operations of the switchboardsshould be carried out at intervals, typically of one year.In addition, routine testing and servicing of the unit’sbatteries and cabinets should be undertaken.

13.34 In a modern tunnel, sufficient redundancy isnormally built into the switchgear design to enableindividual circuit breakers to be withdrawn one at atime, for maintenance without detriment to theoperation of the tunnel. It is essential to verify that theswitchgear operates correctly, particularly under mainsfailure conditions, although it should be noted thatsimulating incoming supply failure does not necessarilymean switching off the incoming supply. It could, forinstance, mean manually operating or disconnecting therelay that detects power failure. If the above cannot becarried out without disrupting power supplies to thetunnel, then suitable procedures will need to bedeveloped to enable the testing to take place duringplanned closures.

Distribution and Control Panels


13.35 There is considerable variation in the design oftunnel panels and their contents. Typically tunnelscontain electrical distribution, emergency distribution,emergency equipment, smoke control, sump control,lighting control, and ventilation control panels.

May 2003

Depending on their location, a lane or bore closure isnormally required for access.

13.36 Maintenance procedures on these items may needto be carried out by authorised persons who havereceived specific training appropriate to work on tunnelelectrical systems. Most procedures will require ‘Permitto Work’ procedures.

Cleaning and testing of panels

13.37 The operation of panel doors and alarms shouldbe tested at intervals, typically of 3 months or duringroutine tunnel closures, whichever is sooner.

13.38 Panel door hinges should be lubricated, doorlatches and ingress protection seals inspected andpanels vacuum-cleaned internally at intervals, typicallyof one year. External faces of the panel doors should becleaned regularly, usually as part of the tunnel cleaningoperations (see Chapter 5).

Cleaning, Inspection, Service and Testing ofEquipment

13.39 Typical operations that should be carried out onelectrical distribution and control equipment within thepanels include:

i. at intervals, typically of 3 months, switchboardsshould be cleaned externally and inspectedvisually for any obvious damage or signs ofdeterioration or malfunctioning. Anti-condensation heaters should be checked. Faultyindicator lamps should be replaced andconfiguration settings and correct installation ofprotective devices checked. Accessible wiringconnections should be checked visually fortightness, chafing and signs of overheating ordeterioration;

ii. at intervals, typically of 6 months, a moredetailed check of all wiring, connections andterminations should be made for signs ofoverheating or damage, and cable entries, glandsand sleeves for fit and deterioration;

iii. at intervals, typically of one year, all control,switching and protective devices should bechecked for correct operation and anydeterioration of contacting surfaces.

13/3



13.40 Visual inspection of electrical connections couldexpose live conductive parts that cannot be readilyisolated without isolating tunnel primary/essentialpower circuits. Therefore the need, extent andfrequency of such inspections should be determinedthrough risk assessment that considers the potentialrisks to the inspector against the probability and natureof the risks that would be realistically avoided througha regime of visual inspections.

May 200313/4


QUIPMENT

Chapter 14Emergency Power Equipment

14. EMERGENCY POWER E

General

14.1 This Chapter provides general guidance onmaintenance of uninterruptible power supply equipmentand standby generators.

Uninterruptible Power Supply (UPS)


14.2 UPS equipment may be used to provideprotection against power supply failure to a limitednumber of systems within a highway tunnel. UPS unitsmay be sufficient to supply systems for a short period(typically thirty minutes) while any standby generators(where provided) are started, or they may be sufficientto provide several hours’ supply on their own. Theprotected systems may include part of the tunnellighting, pumps, environmental monitoring systems,traffic management equipment and computer controlsystems. UPS units are commonly located in tunnelservice buildings and control room buildings. A numberof UPS units of differing capacity may be used toprovide supplies to different systems within a tunnel.

14.3 Traffic management is not required to accessmost UPS units. Consideration should be given to therisk of a tunnel power failure whilst the UPS is shutdown for maintenance. If possible, UPS maintenancework should be carried out during tunnel closures.Additionally, UPS maintenance should not be carriedout at the same time as work on other power supplysystems.

Maintenance

14.4 This should be in accordance with the operationand maintenance manual. Typically, cleaning andinspection should be carried out at intervals of 3months. Servicing is not normally required. Operationshould typically be tested at intervals of 3 months, anda battery discharge test carried out once a year. NickelCadmium (NiCad) batteries require a shorter discharge

May 2003

testing interval.

Standby Generators


14.5 Standby generator sets are typically dieselengines equipped with battery-fed electric startingsystems, an alternator and diesel tanks containingsufficient fuel for several hours of continuous running.The generator sets supply electrical power to criticalsystems during periods of total mains power supplyfailure.

14.6 Traffic management is not normally required toaccess standby generators. However, it should be notedthat when the generator is disabled for maintenanceactivities there is a risk of a tunnel power failure if themain supply is interrupted. Therefore, it is beneficial ifgenerator maintenance work is carried out during tunnelclosures.

14.7 It is very important that maintenance is notcarried out on this item whilst work is being carried outon the main supply, as this would increase the risk of asupply failure to the tunnel. If a failure of any mainssupply occurs during generator maintenance, this workshould be aborted and the generator restored to servicecondition as quickly as possible.

Cleaning

14.8 Cleaning is required typically at intervals of threemonths and should form part of the servicing.

Inspection

14.9 An inspection of the generator should be carriedout at intervals, typically of 3 months.

Service

14.10 Typically at intervals of 3 months, servicingshould include the checking of fluid levels, belts, starterbatteries, vents, leaks and lubrication where necessary.At intervals, typically of one year, servicing shouldinclude a full lubrication and adjustment service.During servicing, checks for any excessive vibration,alarm operations, lights, building and door damageshould be carried out. Repairs to the building housingthe generator should be made as necessary.

14/1


Chapter 14Emergency Power Equipment

Testing

14.11 Typically, a test run of one hour duration, using aresistive load-bank at 100% generator output rating,should be carried out at intervals of 3 months andinclude the following checks:

i. oil pressure and temperature;

ii. engine speed;

iii. exhaust temperature;

iv. load-bank settings;

v. water temperature;

vi. turbo air pressure;

vii. alternator battery charge current and alternatoroutput (ie voltage, current, power, frequency andpower-factor);

viii. battery charger current and voltage prior tostarting;

ix. operation of control panels, associated lamps andalarms.

14.12 Fuel tanks should be refilled immediately oncompletion of each test run.

May 200314/2


PLANT ROOM

Chapter 15Service Building and Plant Room Maintenance

15. SERVICE BUILDING ANDMAINTENANCE

15.1 This Chapter provides general guidance onmaintenance of service building and plant room fabricand building services. Reference should also be made tothe relevant Chapters for equipment housed in thesebuildings, and to Chapter 10 for maintenance of fireprotection systems. Maintenance procedures andintervals contained in tunnel documentation shouldnormally take priority, but should be reviewed inoperation, see Chapter 3.

Building Fabric


15.2 Tunnel service building structures vary betweentunnels. Full access is normally possible without anytraffic management.

Maintenance

15.3 An inspection of the tunnel-service-buildingfabric should be carried out at intervals, typically of oneyear. Depending on its location, more frequentinspection of the service building roof, perimeter andaerials may be necessary, because of vandalism etcTouching up of paintwork and maintenance of the roofshould be carried out at intervals, typically of one year,if need is identified during the inspection. Cleaning ofthe gutters and weeding should also be carried out atintervals, typically of one year.

Heating, Lighting and Ventilation (HVAC)


15.4 Tunnel-service-building systems vary betweentunnels. Access is possible without traffic management.Systems include air conditioning, automatic heating andlighting.

Maintenance

15.5 All aspects of maintenance should be conductedin accordance with the operation and maintenancemanual.

S

DA

1pmc

M

1Brwr

May 2003

ecurity Systems

escription of Typical Equipment and Accessrrangements

5.6 The security system typically may incorporateroximity, vibration and PIR sensors. Trafficanagement is not normally required for access to

arry out maintenance.

aintenance

5.7 Maintenance should be in accordance withS 4737, where typically a maintenance inspection is

equired at intervals of one year on buildings with a bellarning system, and at intervals of six months where

emote signals connect to a central control system.

15/1


Chapter 16References and Glossary of Terms

SSARY OF TERMS
16. REFERENCES AND GLO
16.1 Legislation

The Confined Spaces Regulations

The Construction (Design & Management) Regulations

The Control of Substances Hazardous to HealthRegulations

The Electricity at Work Regulations

The Framework Directive, EC Directive 89/665/EEC

The Health & Safety at Work etc Act

The Highways Act

The Local Government, Planning and Land Act

The Town and Country Planning (Scotland) Act

The New Roads and Street Works Act

The Roads (Scotland) Act

The Road Traffic Regulations Act

16.2 Safety

Health and Safety Executive, Guidance Note EH40:Occupational Exposure Limits (updated annually)

16.3 Emergency Exercises

BD 53 Inspection And Records For Road Tunnels

The Exercise Planners Guide – Home Office (availableon Home Office web site www.homeoffice.gov.uk)

Technical Bulletin 1/1993 Operational Incidents InTunnels And Underground Structures – Home Office

Fire Services Act 1947

16.4 British Standards – British StandardsInstitution, London

BS 1447: Mastic asphalt (limestone fine aggregate) forroads, footways and pavings in building

BS 2853: Specification for the design and testing ofsteel overhead runway beams

May 2003

BS 4737: Section 4.2: Intruder alarm systems inbuildings Part 4: Codes of practice Section 4.2: Code ofpractice for maintenance and records

BS 5628: Part 2: Structural use of reinforced and pre-stressed masonry

BS 5839: Part 1: Fire detection and alarm systems inbuildings

BS 6651: Code of practice for protection of structuresagainst lightning

BS 7671: – Requirements for Electrical Installations,IEE Wiring Regulations, Sixteenth Edition

BS EN ISO 9002: Quality systems model for qualityassurance in production, installation and servicing

16.5 Design Manual for Roads and Bridges – TheStationery Office, London

BD 21 The assessment of highway bridges andstructures. DMRB 3.4.3

BD 27 Materials for the repair of concrete highwaystructures. DMRB 2.3.2

BD 33 Expansion joints for using in highway bridgedecks. DMRB 2.3.6

BD 43 Criteria and material for the impregnation ofconcrete highway structures. DMRB 2.4.2

BD 47 Waterproofing and surfacing of concrete bridgedecks. DMRB 2.3.4

BD 53 Inspection and records for road tunnels. DMRB3.1.6

BD 62 As built, operational and maintenance recordsfor highway structures. DMRB 3.2.1

BD 63 Inspection of highway structures. DMRB 3.1.4

BD 78 Design of road tunnels. DMRB 2.2.9

BA 16 The assessment of highway bridges andstructures. DMRB 3.4.4

BA 26 Expansion joints for using in highway bridgedecks. DMRB 2.3.7

16/1



BA 33 Impregnation of concrete highway structures.DMRB 2.4.2

BA 35 Inspection and repair of concrete highwaystructures. DMRB 3.3.2

BA 47 Waterproofing and surfacing of concrete bridgedecks. DMRB 2.3.5

BA 63 Inspection of highway structures. DMRB 3.1.5

BE 8 Painting of concrete highway structures. DMRB2.4.2

HA 48 Maintenance of highway earthworks anddrainage. DMRB 4.1.3

16.6 Manual of Contract Documents for HighwayWorks – The Stationery Office, London

Volume 1, Specification for Highway Works. MCHW1,including but not limited to:

Volume 5, Section 7, Part 2. Standard PerformanceSpecifications for Mechanical and ElectricalInstallations in Road Tunnels, Movable Bridges andBridge Access Gantries. MCHW 5.7.2

16.7 Trunk Roads Maintenance Manual – TheStationery Office, London)

TRMM Volume 1: Highways Maintenance Code

TRMM Volume 2: Routine and Winter MaintenanceCode

TRMM Volume 3: Management of Health and Safety

RMMS: User Manual for the Highways Agency’sRoutine Maintenance Management System

16.8 Network Communications DocumentsMotorway Communications (MC) – HighwaysAgency TSS Plans Registry, Temple QuayHouse, 2 The Square, Temple Quay, Bristol,BS1 6HA.

MCH 1277 Maintenance Instruction – Responders

MCH 1279 Maintenance Instruction – CommunicationEquipment

MCH 1280 Maintenance Instruction – Indicators

MCH 1332 Maintenance Instruction – Cleaning ofOptical Equipment

16/2

MCH 1349 Maintenance and Operational Requirementsfor New Systems and Equipment

MCH 1350 Liaison with Third Parties

MCH 1381 Reporting NMCS Operational Problems

MCH 1386 NMCS1 and NMCS2 TransmissionEquipment and Circuits

MCH 1399 Notification of a Change in EquipmentQuantities for Maintenance

MCH 1419 Maintenance Instruction – Standby BatteryUnit for 2305A for 617 Transmission Station

MCH 1425 Maintenance Instruction – MotorwayCommunications Cable and Equipment

MCH 1433 Standard Cable Repair Procedures usingJointing Kit Type 1000

MCH 1453 Mini Carrier Systems – RMCResponsibilities

MCH 1454 National Motorway CommunicationSystems – Transmission Standards

MCH 1461 Contractor Reports and Availability/Performance Calculations

MCH 1470 Procedures for the Production of SiteRecords for Maintenance

MCH 1499 Mini Carrier Maintenance Handbook

MCH 1523 Approval of Dedicated Maintenance Teamand Changes

MCH 1526 Maintenance Instruction – NMCS2Transponders

MCH 1527 Maintenance Instruction – NMCS2Responders

MCH 1528 Maintenance Instruction – NMCS2 LCC/DBP Maintenance

MCH 1582 Routine Maintenance of Camera Masts,Poles and Mounting Equipment

MCH 1587 Routine Maintenance of Fog DetectorEquipment

MCH 1590 Maintenance Boundaries Relating toTransmission Station Equipment

May 2003



MCH 1598 Requirements for Repair and Reinstatementof Damaged Motorway Communications EquipmentIncluding Cable

MCH 1626 Routine Maintenance of the EnhancedMessage Signs Stand Alone Controller

MCH 1640 Routine Maintenance – Variable MessageSigns Maidstone Control Office Area

MCH 1644 Maintenance Handover Certificate

MCH 1645 Maintenance Instruction for ContractorsSubmitting Invoices to the Department

MCH 1647 Notification of Cable Damage and Repairs

MCH 1649 Procedure for Contractors using the RCCNetwork for Testing NMCS2 Hardware and Software

MCH 1654 Routine Maintenance of Telemetry T100Units

MCH 1675 Contract Termination Requirements andProcedures

MCH 1685 Enhanced Message Signs: ModemEquipment Maintenance Procedures

MCH 1710 NMCS Operational Problem Report Form

MCH 1740 NMCS1 and NMCS2 TransmissionEquipment and Circuits Procedure

MCH 1743 Testing and Cleaning of RoadsideEmergency Telephones

MCH 1760 National Routine Maintenance Procedures

MCH 1784 M25 Controlled Motorway Pilot Scheme.Enforcement and CMI Equipment Special MaintenanceProcedures

MCH 1793 Controlled Motorway Indicators. RoutineMaintenance Instructions

MCH 1825 M25 Controlled Motorway Pilot Scheme.MIDAS Special Maintenance Procedures

MCH 1844 Routine Maintenance of CCTV Equipment

MCH 1852 NOMAD – Definition of Categories, Typesand Variants.

MCF 2331 Service Specification

May 2003

MCG 1022 Testing for Newly Installed MotorwayCommunications and Power Cables

MCG 1099 NMCS Non-Armoured Cables, InstalledCable Testing Procedures

TR 1173 Multi-pair Communications CablePolyethylene Insulated, Polyethylene SheathedArmoured

TR 1238 Power Cable for Motorway CommunicationSystem (Split Concentric, Armoured)

TR 2017 NMCS Armoured Composite Optical FibreCommunications Cable

TR 2067 NMCS RS485 Standard – Electrical andProtocol

Road Traffic Advisor Project. MaintenanceRequirements Specification

Ducted Cable Infrastructure – Routine MaintenanceRequirements

TRH 1239 National Motorways CommunicationsSystem. Installation Drawings

16.9 World Road Association (formerly PermanentInternational Association of Road Congresses(PIARC)) – British National Committee,World Road Association, Room 4/52,St Christopher House, Southwark Street,London, SE1 0TE

Classification of tunnels, Existing Guidelines andExperiences, Recommendations – 1995

Road Safety in Tunnels – 1995

Road Tunnels: Reduction of Operational Cost – 1999

16.10 Other References

Association of County Councils (1989) Highwaymaintenance: a code of good practice. Published by theAssociation of County Councils, London on behalf ofthe Association of County Councils, Association ofDistrict Councils, Association of MetropolitanAuthorities and the Convention of Scottish LocalAuthorities.

Atkinson K (1997). Introduction, in: Highwaymaintenance handbook, edited by Atkinson K. ThomasTelford Publications, London.

16/3



Barnard C P and J R Cuninghame (1997). Practicalguide to the use of bridge expansion joints. TRLApplication Guide 29. Transport Research Laboratory,Crowthorne.

Bird S, J E Potter, D M Hiller and K H Bowers (2000).Value management for tunnel procedures. TRL Report448. Transport Research Laboratory, Crowthorne.

Department of Transport, Bridge Inspection Guide(1983), HMSO, London.

Evans, A, S Bird, K H Bowers, G I Crabb and R HHarse (2000). Value engineering for tunnel equipment.TRL Report 449. Transport Research Laboratory,Crowthorne.

Ford RJ (1998). Operation And Maintenance Of RoadTunnels: Maintenance Engineers Conference:University of Nottingham: September 1998,“Surveyor”.

Ford R J (1999). Reducing Road Tunnel OperatingCosts: Trunk Road Management Annual Conference:University Of Nottingham: September 1999,“Surveyor”.

Ford R J (2000). Operational Risk Management OfRoad Bridges And Tunnels.

Guidance on Risk Assessment at Work: Health andSafety: European Commission, 1996.

Highways Agency (1996). The Value for MoneyManual. The Stationery Office. London.

Highways Agency (1996). User Manual for theHighways Agency’s Routine Maintenance ManagementSystem. The Stationery Office, London.

Highways Agency (1999). Trunk Road MaintenanceManual. The Stationery Office, London.

Management of Safety at Work Regulations of 1992:HSC Approved Code of Practice 1992 (Revised 1999/2000).

Page J (1996). A guide to repair and strengthening ofmasonry arch highway bridges. TRL Report 204.Transport Research Laboratory, Crowthorne.

Risk Priority Number (RPN) Method: Trunk RoadManagement Conference: University of Nottingham:September 2000, “Surveyor”.

16/4

Sumon S K (1998). Repair and strengthening of three-ring-brick masonry arch bridges. Proc FifthInternational Masonry Conference, London, 1998.

Zuman N (1997). Street lighting and illuminated trafficsigns, in: Highway maintenance handbook, edited byAtkinson K. Thomas Telford Publications, London.

16.11 Glossary of Terms

CCTV Closed Circuit Television

CDM Regulations Construction (Design andManagement) Regulations

CHART Computerised HighwaysAssessment of Ratings andTreatments

COSHH Control of Substances Hazardousto Health

DMRB Design Manual for Roads andBridges (Highways Agency)

DO Design Organisation

DOL Direct-on-Line

ECS Environmental Control System

FMEA Failure Modes and Effects on anAsset

HRM High Speed Road Monitor

HV High Voltage

IEE Institution of ElectricalEngineers

LEL Lower Explosion Level

MA/NMMA Maintaining Agent/NewManaging and MaintenanceAgent

MCF Mercury Low PressureFluorescent (lamp)

NiCad Nickel Cadmium

NMC National Maintenance Contractor

NMCS National MotorwayCommunications System

NTS National Transmission System

QA Quality Assurance

PLC Programmable Logic Controller

RMC Regional MaintenanceContractor

May 2003



RMC–MC Regional Maintenance Contracts– Management Consultants

RMMS Routine MaintenanceManagement System (HighwaysAgency)

SCADA Supervisory Control and DataAcquisition

SON-T Tubular High Pressure Sodium(lamp)

SOX Low Pressure Sodium (lamp)

TDSCG Tunnel Design and SafetyConsultation Group

TMC Term Maintenance Contractor

TOA Tunnel Operating Authority

TRMM Trunk Road MaintenanceManual (Highways Agency,1999)

UPS Uninterruptible Power Supply

VCS Visual Condition Surveys

VFMM Value for Money Manual

VMS Variable Message Sign

May 2003 16/5


May 2003 17/1

17. ENQUIRIES

All technical enquiries or comments on this Advice Note should be sent in writing as appropriate to:

Divisional DirectorRoom 913Sunley TowerPiccadilly PlazaManchester Andrew JonesM1 4BE Divisional Director

Chief Road EngineerScottish Executive Development DepartmentVictoria QuayEdinburgh J HOWISONEH6 6QQ Chief Road Engineer

Chief Highway EngineerTransport DirectorateWelsh Assembly GovernmentLlywodraeth Cynulliad CymruCrown Buildings J R REESCardiff Chief Highway EngineerCF10 3NQ Transport Directorate

Assistant Director of EngineeringDepartment for Regional DevelopmentRoads ServiceClarence Court10-18 Adelaide Street D O’HAGANBelfast BT2 8GB Assistant Director of Engineering

Chapter 17Enquiries


FF STRUCTURE AND

Appendix ATypical Staff Structure and Profile

APPENDIX A TYPICAL STAPROFILE

A.1 The Tunnel Manager should be a CharteredEngineer with suitable experience in a seniormanagement position. He has overall responsibility formatters relating to the administration, operation andmaintenance of tunnels and, possibly, parts of theadjacent road network.

A.2 The Deputy Tunnel Manager should be anexperienced Chartered Engineer or IncorporatedEngineer who would take responsibility for alldelegated matters in the absence of the TunnelManager.

A.3 The Chief Electronics, Electrical, Mechanicaland Civil Engineers should be experienced Chartered(or near Chartered) Engineers or IncorporatedEngineers and would undertake such duties that enablecontinuing safe and efficient operation and maintenanceof the tunnel. Some of the engineering functions may becombined, depending upon the complexity of theoperation and the experience of the personnel involved.

A.4 Support Engineers/Technicians provide a ‘firstline’ maintenance and operational support function.They will also provide an out of normal working hoursemergency facility. They should normally be qualifiedto HNC level. Additional duties may includesupervision of contractors, the management of ‘Permitto Work’ systems, assisting and directing maintenancetype improvement works. Civil Engineers for examplewould manage the civil assets in respect of maintenanceinspections, control of any specialist ConsultingEngineers and programming capital infrastructureschemes. Other engineers would carry outcorresponding functions.

A.5 Operations Managers would be available, on ashift basis, to the Control Room on a 24 hour,continuous basis. They perform all relevant dutiesrelating to the operation of the tunnels and, possibly, theadjacent road network. They should have a backgroundof operational experience together with anunderstanding of control and monitoring systems.

A.6 The Administration Manager is responsible forall office functions, including financial control ofincome and expenditure, preparation of documentationrelating to maintenance contracts and other generalduties.

Afopw

May 2003

.7 The Quality Assurance Manager is responsibler all aspects of quality, including the preparation of

lans and procedures. These should be maintainedithin the Quality Assurance Manual for the TOA.

A/1

Volume 3 Section 2

Part 3 BA

72/03NOTIONAL ORGANISATION OF A TUNNEL OPERATING AUTHORITY (TOA)

Some of the engineering functions may be combined, depending upon the extent of the tunnel, the complexity of the operation and the experience of the

s AdministrationManager

QualityAssuranceManager

RMC-MC

RMC)

Liaison

Liaison

A/2

Appendix A

Typical Staff Structure and Profile

May 2003

personnel involved.

Tunnel Manager

Deputy Tunnel Manager

ChiefElectronicsEngineer

ChiefMechanical

Engineer

ChiefElectricalEngineer

ChiefCivil

Engineer

OperationManager

SupportEngineer/

Technician

SupportEngineer/

Technician

SupportEngineer/

Technician

SupportEngineer/

Technician

Term Maintenance Contractor (complete with specialist sub-contractors


ON SAFETY DURINGND INSPECTIONS

Appendix BGuidance on Safety During Maintenance Works and Inspections

APPENDIX B GUIDANCEMAINTENANCE WORKS A

See BD 78 for more details.

Traffic Control

B.1 Special traffic conditions involving lanerestrictions, contra-flows or closures, may be createddepending upon the scale of the work and the layout ofthe tunnel. Equipment already provided for trafficcontrol should be supplemented with additional signing,cones etc PIARC C5 Report (Brussels 1987): - Signingin the Case of Works Inside Tunnels provides furtherguidance.

B.2 Temporary signing is an onerous and dangerousprocess. Police assistance should be sought at laneclosing/opening stages and in enforcing speed limits.

B.3 Protection of the workforce in a closed lane of abore may require vehicle speeds to be physicallyrestricted in the running lanes to say 15 mph. This willhelp limit air velocities and allow maintenance to becarried out safely whilst letting traffic flow through thebore.

B.4 Protection should also be provided from vehicleswhich may try to enter a closed tunnel bore or lane.

B.5 Traffic can produce excessive noise levels. It canalso produce turbulent air conditions which withpositive and negative (suction) pressures and other airspeed hazards can unbalance those on foot or workingat height.

B.6 Projections from vehicles can hit workers orunbalance working platforms etc.

Equipment Settings

B.7 Effect of safety items being temporarily out ofoperation during the maintenance works should beconsidered. Where possible work on equipment shouldbe carried out in workshops away from the tunnel.

B.8 Lighting and ventilation may have to beenhanced to cope with possible higher pollution levelsarising from changed traffic conditions.

May 2003

Access Procedures

B.9 Those entering the tunnel should be aware of therules and procedures for lane and tunnel closures.Instructions should be simple and clear. Entry and exitshould be controlled and details of work which mayaffect the traffic or tunnel services obtained and actedupon.

B.10 Tunnels with mechanical ventilation should bepurged of vehicle pollution prior to entry. Those withnatural ventilation may need time to clear and prior toentry, readings of CO, NO2 etc should be taken usingpersonal gas monitors.

B.11 Intruder Alarm Systems should be switched offon entry and re-activated on exit.

B.12 Fire extinguishing systems in Halon or CO2protected rooms should be “locked off” prior to entryand re-activated on exit.

B/1


ON HEALTH AND

Appendix CGuidance on Health and Safety Legislation

APPENDIX C GUIDANCE SAFETY LEGISLATION

General

C.1 Major health and safety legislation affects thosewho operate and maintain tunnels. The primary one forcompliance by employers and employees is The Healthand Safety at Work etc Act 1974 (HSWA). In NorthernIreland, Health and Safety at Work (NI) Order 1978applies.

C.2 The HSWA is supported by Regulations, Codesof Practice and Guidance Notes issued from time totime which lay down more specific requirements. Thesecan be applicable across all industries eg. the Control ofSubstances Hazardous to Health Regulations or betargeted at particular sectors eg. the Construction(Design and Management) Regulations.

C.3 A breach of a provision of a Regulation is acriminal offence and can lead to prosecution.

C.4 Approved Codes of Practice (ACoPs) approvedby the Health and Safety Commission or Health andSafety Executive Northern Ireland give guidance on thegeneral requirements of Acts and Regulations. An ACoPcan be changed to keep it up to date with currentpractice without changing the law. Failure to complywith an ACoP is not an offence in itself but the onus ison the defendant to prove that he complied in someother acceptable way.

C.5 Guidance Notes are produced by the Health andSafety Commission and the Health and SafetyExecutive and Health and Safety Executive NorthernIreland as opinions on good practice. Whilst they haveno legal force they will be used in determining goodpractice and what is ‘reasonably practicable’ in aparticular industry.

Criminal/Civil Law

C.6 The Acts and Regulations mentioned above arestatute law. Failure of a corporate body or an individualto comply with the provisions of these documents is acriminal offence. Those who transgress these laws runthe risk of prosecution by the HSE or, in the case ofmanslaughter, by the Crown Prosecution Service(Procurator Fiscal in Scotland, Director of PublicProsecutions in Northern Ireland).

May 2003

C.7 Employers also have obligations under commonlaw, which has been established over time, and owe aduty of care to their employees to provide a safe placeof work. Those found guilty of an offence whenprosecuted under common law have also committed acriminal offence.

C.8 By their very nature proceedings under healthand safety legislation often result from accidents whenpeople have been injured or killed. The injured party orhis/her dependants may choose to pursue an actionunder civil law for compensation due to the negligenceof the defendant. Thus a single incident can lead to bothcriminal and civil proceedings in different courts of law.The standard of proof required under criminal law(beyond all reasonable doubt) is usually much higherthan under civil law (balance of probabilities).

Other relevant legislation

C.9 These include:

a) Management of Health and Safety at WorkRegulations;

b) Workplace (Health, Safety and Welfare)Regulations;

c) Construction (Design and Management)Regulations;

d) Confined Spaces Regulations;

e) Control of Substances Hazardous to HealthRegulations;

f) Electricity at Work Regulations;

g) Noise at Work Regulations;

h) Personal Protective Equipment at WorkRegulations;

i) Provision and Use of Work EquipmentRegulations.

C/1


May 2003

APPENDIX D EXAMPLES OF DETAILEDMAINTENANCE SCHEDULES FOR LIGHTING ANDVENTILATION

System: Tunnel Lighting Unit Identifier: Base lighting luminaires (rows 1&6)

Unit Description: The tunnel base lighting comprises two rows of 1 x 58 W dimmable fluorescent luminaireswhich extends for the full length of the tunnel. Base lighting comprises Stages 1,2 & 3 which correspond to30%, 60% and 100% luminaire output, controlled via the ECS. Luminaires are constructed from extrudedaluminium alloy housing, with end caps of cast aluminium. The exterior finish is a paint powder epoxy in black.The unit incorporates removable gear tray and reflector/lamp assembly. Approx weight 22 kg. One in every 12luminaires is fed from UPS Supply.

Number of Units: 1221 Maintenance Freq: 12 Months Manual Ref: Volume 4

Drawing Ref: C3/1-33 Location of Equipment: Westbound bore

Maintenance Tasks:

a) Externally clean all the luminaires.b) Relamp/replace or repair any failed luminaires - refer to manufacturer’s maintenance instructions.c) Check luminaire flexible connections from junction box. Ensure that IP65 sealing standard is maintained.

Repair/replace components as necessary.

Items Completed (Tick for Yes): a b c

Special Requirements:

Permits Required YES NO Traffic Management YES NORequired

Type of Permit: Any Special Handling/Lifting Requirements to1] Permit to Access 4] LV Permit to Test Carry out Task:2] LV Permit to Work 5] HV Permit to Test Cranes Fork Lifts3] HV Permit to Work 6] HV/LV Permit to Work Scissors Lifts Fan Cradles

or, Test (Hazardous Areas)Signature:Date:

Appendix DExamples of Detailed Maintenance Schedules for Lighting and Ventilation

D/1


May 2003

System: Tunnel Lighting Unit Identifier: Base lighting luminaires (rows 1&6)




Maintenance Tasks:


Repair/replace components as necessary.d) Relamp all row 1 and 6 luminaires.

Items Completed (Tick for Yes): a b c d





D/2



May 2003

System: Tunnel Lighting Unit Identifier: Boost lighting luminaires (rows 2, 3, 4& 5)

Unit Description: The tunnel boost lighting comprises rows 2, 3, 4 and 5 which is made up of both fluorescentand SON-T luminaires. They make up stages 4, 5, 6, 7 and 8 which are controlled via the portal photometers, theluminaires being switched on at preset lighting thresholds via the ECS. The SON-T lamps are made up of:150 W, 250 W and 400 W units (all double) and the fluorescent 2 x 50 W units. Luminaires are constructed fromextruded aluminium alloy housing, with end caps of cast aluminium. The exterior finish is a paint powder epoxyin black. The unit incorporates removable gear tray and reflector/lamp assembly. Each unit weighs approx 25 kg.

Number of Units: 574 in total Maintenance Freq: 12 Months Manual Ref: Volume 4


Maintenance Tasks:


Repair/replace components as necessary.







D/3


May 2003

System: Tunnel Lighting Unit Identifier: Boost lighting luminaires (rows 2, 3, 4& 5)




Maintenance Tasks:

a) Relamp/replace or repair any failed luminaires - refer to manufacturer’s maintenance instructions.b) Check luminaire flexible connections from junction box. Ensure that IP65 sealing standard is maintained.

Repair/replace components as necessary.c) Change SON-T lamps as per the site instructions of TNG staff.






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May 2003

System: Tunnel Ventilation Unit Identifier: Ventilation Fans

Unit Description: 600 mm diameter reversible jet fan unit manufactured by Company A and comprises a centralfan unit with acoustic silencers mounted at each end. The fan is driven by a 12 kW motor at 2900 rpm. The unitsare suspended from the tunnel ceiling on mounting frames with anti-vibration mountings to isolate any fanvibrations. The fan impeller consists of a central hub onto which is mounted six cast aluminium blades. Fans aremounted in 9 rows of 4 longitudinally along the tunnel.



Maintenance Tasks:

a) Visually check each fan for any obvious damage/defect.b) Clean dirt build up from impeller blades.c) Clean interiors of silencers and dust the exteriors.d) Run fans in both directions and check for signs of any undue vibration/noise.e) Ensure the fan mountings are in good order and correctly tightened.f) Check fan terminal-box connections for tightness.

Items Completed (Tick for Yes): a b c d e f






D/5


May 2003


Unit Description: 600 mm diameter reversible jet fan unit manufactured by Company A and comprises a centralfan unit with acoustic silencers mounted at each end. The fan is driven by a 12 kW motor at 2900 rpm. The unitsare suspended from the tunnel ceiling on mounting frames with anti-vibration mountings to isolate any fanvibrations. The fan impeller consists of a central hub onto which is mounted six cast aluminium blades. Fans aremounted in 9 rows of 4 longitudinally along the tunnel.



Maintenance Tasks:

a) Visually check each fan for any obvious damage/defect.b) Clean dirt build up from impeller blades.c) Clean interiors of silencers and dust the exteriors.d) Run fans in both directions and check for signs of any undue vibration/noise.e) Ensure the fan mountings are in good order and correctly tightened.f) Check fan terminal-box connections for tightness.g) Check fan blade clearances and, if necessary, adjust by means of stay rods holding the motor.h) Check security and condition of anti-vibration mountings.I) Check tightness of main support beam bolts holding tunnel fan mounting brackets to tunnel roof.j) Measure and record fan starting and running currents in each direction.k) Take vibration readings for each fan as defined by the relevant British Standard.l) Carry out insulation resistance tests of each fan circuit.

Items Completed (Tick for Yes): a b c d ef g h i jk l





D/6



May 2003


Unit Description: 600 mm diameter reversible jet fan unit manufactured by Company A and comprises a centralfan unit with acoustic silencers mounted at each end. The fan is driven by a 12 kW motor at 2900 rpm. The unitsare suspended from the tunnel ceiling on mounting frames with anti-vibration mountings to isolate any fanvibrations. The fan impeller consists of a central hub onto which is mounted six cast-aluminium blades. Fans aremounted in 9 rows of 4 longitudinally along the tunnel.

Number of Units: 36 Maintenance Freq: 5 Years Manual Ref: Volume 6


Maintenance Tasks:

a) Carry out complete overhaul of jet fan unit as per manufacturer’s instructions to include the following:Inspect and test motor plus replacement of motor bearingsReplacement of perforated acoustic housing sheet with stainless steel perforated sheetBead blast impeller and carry out NDT with dye penetrantDegrease all painted surfaces, spot prime any damaged areas and paint to conform with originalspecification

b) Replace all anti-vibration mountings with new units.

Items Completed (Tick for Yes): a b






D/7

Volume 3 Section 2

Part 3 BA

72/03

May 2003

APPEN

DIX

ETY

PICA

L TUN

NEL C

LOSU

RE

SCH

ED

UL

E

The Table illustrates the typical cyclic nature of maintenance works and how they could be programmed to minimise tunnel closures.

Strategic Maintenance Plan

Task Name Year 1 Year 2 Year 3

J F M A M J J A S O N D J F M A M J J A S O N D J F M A M

Eastbound 3 Monthly Routine Maintenance



Eastbound 12 Monthly Luminaire Clean

Eastbound 2 Yearly Routine Maintenance

Eastbound 5 Yearly Routine Maintenance

Westbound 3 Monthly Routine Maintenance



Westbound 12 Monthly Luminaire Clean

Westbound 2 Yearly Routine Maintenance

Westbound 5 Yearly Routine Maintenance

Split Annual Routine Maintenance (Phase I)

Split Annual Routine Maintenance (Phase II)

Split Annual Routine Maintenance (Phase III)

Split Annual Routine Maintenance (Phase IV)

Split Annual Routine Maintenance (Phase V)

External Equipment 5 Yearly Routine Maintenance

Service Buildings 5 Yearly Routine Maintenance

Appendix E

Typical Tunnel Closure Schedule

E/1


N EMERGENCY

Appendix FGuidance on Emergency Exercises

APPENDIX F GUIDANCE OEXERCISES

Introduction

F.1 During the planning and design of a road tunnelpotential incidents and emergencies should be identifiedand related to the tunnel layout and to standards ofequipping communications, traffic information andcontrol systems. Formal risk assessments should becarried out and recorded for each of the identified riskscenarios. Having identified, defined and ranked thescenarios, appropriate response strategies should bedeveloped to deal with them and incorporated into theTunnel Operator’s Manual and the Operational Manualsof the Police and the Emergency Services.

F.2 It is important to test the effectiveness of suchresponse strategies in a realistic exercise before thetunnel is opened to traffic and amend them based onlessons learnt from the exercise. It is good practice forthe future tunnel operator to be fully involved with theexercise.

F.3 The same procedures are applicable when a roadtunnel is refurbished, modified or when there is anychange in the organisations operating the road tunnel orattending emergencies.

F.4 Regular emergency exercises should be carriedout throughout the operational life of the tunnel toensure the continued effectiveness of the plannedresponse strategies. It is common practice in the policeand the emergency services for personnel to be rotatedbetween postings. Regular emergency exercises helpthe new staff to become familiar with the responsestrategies and the road tunnel and to meet colleaguesfrom the other services and develop good relationshipsin a non-critical setting.

Requirement

F.5 The requirement is defined in BD 53 (DMRB3.1.6).

Frequency of Exercises

F.6 Exercises should be undertaken:

a) before a new tunnel is opened to traffic;

b) when a tunnel is modified or refurbished;

May 2003

c) as part of the Principal Mechanical & Electricalinspection, which is normally carried out every 3years.

Objectives

F.7 An emergency exercise has the followingobjectives:

a) to demonstrate the adequacy of response by theemergency services;

b) to test the planned response strategies in theTunnel Operator’s Manual and the OperationalManuals of the Police and the EmergencyServices;

c) to test emergency services’ procedures andeffectiveness of their training methods in dealingwith large-scale accidents/incidents in the tunnelhaving regard to inter-service liaison;

d) to test and familiarise all parties with the varioustunnel services including power supplies,lighting, ventilation, environmental control,communications, fire fighting, security andtraffic surveillance and management;

e) to provide practical combined training for theparticipants representing the three principalemergency services and the tunnel operatingauthority;

f) to demonstrate the correct operation of all safetyand emergency equipment for the road tunnel;

g) to test the validity of any assumptions made.

Further guidance

F.8 Generic guidance to design and carry outemergency exercises is available in “The ExercisePlanners Guide” published by the Home Office. Alsoavailable on the website: www.homeoffice.gov.uk.

F.9 Further guidance specific to road tunnels can beobtained from: [email protected].

F/1