Annexure-III Chimney Spec[1]

8/11/2019 Annexure-III Chimney Spec[1].

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SPECIFICATION FOR CIVIL, STRUCTURAL &ARCHITECTURAL WORKS GMR ENERGY LIMITED

FOR MAIN POWER BLOCK AREA

Doc. No. K8V07-GEL-SPC-008Project

1200-1320 MW THERMAL POWER PLANTCHHATTISGARH, INDIA

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Anx-III Date: 25-11-2008 Page 1 of 31

CHIMNEY

1.00.00 SCOPE OF WORK

1.01.00 The scope of work covered in this specification in general, comprises thedesign construction & commissioning of 275 m high twin flue RCC Chimneyrequired for 1200 1320 MW power plant of GMR Energy Limited at RaipurDistrict, Chhattisgarh, India.

1.02.00 The scope of work shall consist of but not be limited to the following:

a) Preparation of design basis report, design and constructiondrawings and obtaining approval.

b) All excavation works in all types of soils/rocks including dewateringas necessary.

c) Providing and laying of grounding mat

d) Construction of pile/raft foundation

e) Backfilling around the foundation

f) RCC shell

g) Internal platforms with flue restraint bearing and top internal platformwith support bearing & External platforms

h) Hopper

i) Steel Flues, stainless steel flues of suitable height above chimneyroof slab.

j) RCC corbels at intervals

k) Chimney cap

l) Companion flange and brackets including inserts on the shell for the

flue duct connection.

m) Access, maintenance and clean out doors

n) Staircase, ladders and hand railings


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o) Insulation material.

p) Platforms, inserts & miscellaneous bolts and anchors required forinstrumentation of chimney.

q) Lightning protection and grounding systems.

r) Arrangement for maintenance on outer face of chimney at top.

s) All painting work including for aviation, day warning painting as peraviation requirements.

t) Aviation night warning lights, lighting system inclusive of allaccessories and cabling work from power supply point.

u) Installation of lights at all external platforms.

v) Providing and installation of rack and pinion elevator of 400 kgcapacity with (G+27) landing platform.

w) Providing expansion compensators to steel flues.

1.03.00 Some other tall structures i.e. Cooling Towers and chimneys are located inclose vicinity of the Chimney. The aerodynamic interference effect due tothese shall be studied and incorporated in the design of the Chimney. Windtunnel model study for determining the aerodynamic interference isincluded in the bidders scope. The study shall be done by a specialistagency in this field acceptable to owner.

1.04.00 The works covered in this specification shall include furnishing of allmaterials, labour, tools, plant and equipments, transportation, fabrication,supervision, construction as per drawings including embedment of bolts,inserts, leaving holes, pockets, grooves, chamfers as shown therein and allincidental items not shown or specified but reasonably implied of necessaryfor satisfactorily completion of the project as a whole.

1.05.00 It is not the intent to specify completely herein all details of design andconstruction of the works covered under this specification. All works shallbe done as per specification and approved for construction drawings and ina manner acceptable to Engineer; who shall have the power to reject anywork or material which in his judgement is not in full accordance therewith.

In case of any conflict regarding the interpretation of the intent or meaningof the specifications or drawings, Engineer shall interpret such intent ormeaning, which will be final and binding on the contractor.

1.06.00 Contractor shall rectify and make good all defective work during the defectsliability period of 12 months from the date of commissioning.


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1.07.00 Attending meetings at Owner/Consultants office at Mumbai or any otherplace as fixed by Engineer as and when required for review, discussions,co-ordination etc.

1.08.00 Making all necessary arrangements for access to the storage yard from thenearest approach road and further to the actual site of work includingdewatering as necessary, and maintenance of same in order to facilitatetransportation of machinery and equipment such as cranes etc assessingthe suitability of already existing access roads.

1.09.00 All other works not specifically mentioned above but indicated in thedrawings, which are necessary for the satisfactory completion of the workas a whole.

1.10.00 Necessary grooves, holes etc. shall be provided in the structure for erectionof the elevator.

2.00.00 GENERAL

2.01.00 General parameters of the Chimney

1 Total height or the chimney above : 275 mgrade level

2 Multi flue R C C Wind shield (shell)enclosing two flues, one for each500MW Boiler

3. No. of Boilers : Two4. Volume of Gas per Boiler : 790 m3/sec5. Mass flow of Gas : 2332 T/h6. Density of gases : 0.82 kg/m3

7. Temperature of flue gases : 134 C8. Inlet-duct Centre line elevation : During Detail Engg.9. Duct opening Dimensions : During Detail Engg.10. Internal diameter of flue : 6300 mm11. Maximum ambient temperature :12. Minimum ambient temperature :13. Each flue of the chimney shall be

Connected to one of 500 MW steamGenerator boiler.

14. Top of Foundation level : 2 m below

grade level (min)15. Allowable Soil Bearing capacity : Ref: Soil Report

(NETT)16. Minimum top internal shell diameter : 16 m17. Minimum bottom internal shell : Bidder to decide.

diameter


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18. Flue gas pressure at Chimney entry : During Detail Engg.level

2.02.00 The Chimney shall be 275 m high RCC Chimney comprising of two nos

acid and heat resistant steel flue encased by windshield of reinforcedconcrete shell. The flue ducts shall be entering from diagonally oppositeends.

2.03.00 Five numbers of external platforms excluding Hood Platform, with minimumclear width of the platforms as 1.0 M shall be provided at an interval ofapprox. 40.0 M. These platforms shall be spaced approximately equallybetween the Hood platforms and ground level.

2.04.00 All internal platforms, supporting liners, shall be supported on R.C.C. shellof the chimney. Access doors at grade level and external platform levelsshall be provided for access into the shell at finished grade level and foraccess to external platforms. The clean out doors shall also be provided inthe steel liners.

3.00.00 CODES AND STANDARDS

a) IS:456-2000 : Code of practice for plain andReinforced Concrete

b) IS:4998 (Part 1-1992) : Design Criteria for ReinforcedConcrete Chimney

(Read in-conjunction with IS 4998-1975.)

c) IS:875 (Part 3-1987) : Code of Practice for Wind Load

d) IS:1893 (Part-1 & Part-4) : Criteria for Earthquake ResistantDesign of Structures.

e) IS:432 (Part-I) : Mild steel and Medium steel Bars.

f) IS:1786 : Cold twisted steel bars for ConcreteReinforcement

g) IS:800 : Use of Structural steel in generalBuilding Construction

h) ACI Standards

i) Reference may also be made to ACI: 307 Specification for designand construction of R.C. Chimney if some items are not covered inIndia Codes.


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4.00.00 MATERIALS TO BE USED

Chimney foundation shall be in concrete grade M-25 with minimum cement

content of 365 kg/m

3

. Chimney shell shall be of min. concrete grade M-25with minimum cement content of 400 Kg/m3. The cement shall be 43 gradeOPC. Reinforcement shall be Fe-415 steel. Only one grade of concreteshall be used throughout the height of the shell.

5.00.00 LOADING ON THE STRUCTURE AND THEIR COMBINATION

5.01.00 Dead Load

All permanent loads due to the weight of chimney shell, internal platformsand linings supported on them, flue ducts, staircases, other accessories,etc.

5.02.00 Imposed Loads

i) Imposed load on service platform around Chimney shell, shall betaken as 500 kg/m2. Design live load during construction/ erectionshall be considered as 1000 kg/m2.

ii) Imposed loads from duct joining the Chimney shall be considered.

5.03.00 Wind Load

5.03.01 The wind loading shall conform to IS:875 (Part-3) : 1987. Dynamicanalysis shall be carried out and stability ensured under such condition.The details shall be as per Cl. 6.0 of this design basis.

Wind parameters shall be considered for calculating design wind speed andpressure shall be as follows :

Basic wind speed = 39 m/s (Up to 10m above normal ground level)

K1 = 1.06 as per IS: 875 Table-1

K3 = 1.0

K2 = (Table 2. Category-2. Class-C)

The final design will be checked and verified, as per wind tunnel test, by areputed institute and if needed, modifications to be carried out at no extracost.

5.04.00 Seismic/ Earthquake Load


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Earthquake forces acting on the Chimney and analysis for the same shallbe carried out as per IS:1893 (Part 1 & 4) using the Response SpectrumMethod and 5% damping shall be considered for the analysis. The

importance factor of 1.75 shall be used. The analysis shall be furnished fora combination of five modes (minimum).

5.05.00 Thermal Effect

Due to the effect of temperature gradient, vertical and circumferentialstresses are developed. These stresses induced in the concrete shall notexceed values given in IS:4998.

Flue Gas Data (To be confirmed by BTG SUPPLIER)

Flue gas temperature at inlet =134C

Acid dew point of the gas =137C Exit gas velocity at top of the Chimney = 25 m/s

The temperature gradient T across the shell thickness will be calculatedas per IS: 4998 (Part-I) 1975 but subject to a minimum of 30C.Temperature stresses will be calculated according to the procedures givenin ACI-307 and IS:4998 (Part-1) 1975.

Vertical and circumferential reinforcement shall be provided for temperaturestresses.

5.06.00 Local Loads

The effect of following local loads is considered :

a) Local moment produced by corbels (if any).

b) Local moment due to platforms.

c) Local moment due to occurrence of ovalling.

d) Local moment produced by thermal gradient.

5.07.00 Load Combination

Various load combinations for calculation of stresses shall be as under:

a) Dead load + Wind load


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b) Dead load + Earthquake forces.

c) Dead load + Temperature effect.

d) Dead load + Wind load + Temperature effect.

e) Dead load + Earthquake force + Temperature effect.f) Circumferential stresses due to temperature effect.

g) Circumferential tensile stresses due to wind inducing ring moment.

h) Circumferential compressive stress due to wind induced ring momentcombined with temperature

In Load combinations (a) to (f) above, dead load considered shall be with orwithout the weight of lining, whichever condition is more critical, shall beadopted for design. Across wind loads shall be combined with co-existingalong wind loads. The combined design moment at any section shall betaken as SRSS of the moments due to across wind loads and co-existingalong wind loads.

6.00.00 PERMISSIBLE STRESSES FOR CHIMNEY SHELL

The stresses in steel reinforcement and concrete shall not exceed the limitsas prescribed in clause 7.0 of IS 4998 (Part I)-1975 for variouscombinations of loads. Except for case of dead load + wind load themaximum permissible stress in concrete in this case shall not exceed 0.32FC where FC= Characteristic compressive strength of concrete in kg/cm

2

7.00.00 ANALYSIS

7.01.00 Free Vibration Characteristics of Shaft

Calculation of Natural Frequencies and mode shapes shall be carried out.For this purpose the chimney shaft shall be idealized as a vertical cantileverwith lumped masses at different nodes. The nodes shall be provided ateach platform level.

Minimum 5 mode shapes shall be considered.

7.02.00 Wind Analysis

7.02.01 Along Wind or Static Analysis


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The basic wind speed Vbat Raipur, Chattisgarh according to IS 875 (Part-3) 1987 is 39 m/sec. The terrain category is 2 with K1 = 1.06, K2 as pertable 2 of IS-875 (Part-3) 1987 for class C structure and K3=1.0

The gust factor will be calculated according to the method given in IS-4998 (Part 1) 1992. Dynamic modulus of Elasticity of concrete asrecommended in IS: 4998 (Part-1) 1992 will be used for calculating thenatural frequencies of the chimney.

Cdwill be taken as 0.8 for the concrete shell in general. It will be increasedas per table-1of IS: 4998 over the portion covered with strakes, if required.

Along wind response of chimney shall be calculated both by gust factormethod in A-5.1 and simplified method in A-4.1 of IS: 4998 part-1, 1992.For design, higher of the along wind loads shall be used.

7.02.02 Across Wind

The across wind response of the Chimney will be evaluated as per themethod given in Section A-4 as well as A-5 of IS: 4998 (Part-I)-1992. CLwill be taken as 0.16 and S=0.2. Higher of the two moments shall beconsidered for design of the Chimney.

7.02.03 Ring Moments Due to Wind.

The circumferential ring moment due to wind will be calculated inaccordance with clause 5.4 of IS:4998 (Part-1) 1992. The wind inducedstresses in concrete and steel shall be calculated in accordance with cl noD-2.2.7, D-2.2.8 and D-2.2.9 of IS 4998 (part 1) 1975.

7.03.00 Seismic Analysis

The Seismic Analysis will be carried out using the response SpectrumMethod according to IS:1893 taking the first 5 modes of vibration intoaccount. Raipur, Chhattisgarh is in Zone II of IS 1893. The importancefactor of 1.75 and 5% damping shall be considered for the analysis.

8.00.00 COMPONENT DESIGN CRITERIA

8.01.00 Shell and Foundation

The design conditions for the concrete shell shall be as follows:


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1. The concrete shell shall be designed for natural phenomena andloads and loads combinations as specified in clause 4.07. Workingstress method shall be used for design of shell. The modular ratio

shall be calculated as per Annexure B of IS 456-2000.

2. The concrete shell shall support all platforms, which in turn providesupport for two independent liners. The beams supporting theplatform shall be made to rest on the shell by making a pocket in theshell. Below steel beam and above concrete surface electrometricbearing pads are to be provided. Individual pads for separate floorsare to be design against temperature load and horizontal shear dueto seismic loads.

3. The permissible stress in concrete and reinforcement shall belimited to as specified in clause 6.0. The stress in concrete at thejunction of shell and foundation will be limited to 0.32 Fc. Where Fc isthe characteristic compressive strength of weaker concrete betweenshell and foundation.

4. The thickness of RCC shell shall be provided as required by stresscalculations, however, the thickness of shell has also to bedetermined in the basis of wind tunnel model studies and anyincrease in the thickness of shell or quantities required to be madeas per report shall be followed without any extra cost.

5. The maximum deflection at the top of the chimney for both staticand dynamic cases shall not be more than H/500 where H is thetotal height of the windshield above top of the pile cap.

6. The dynamic modulus of elasticity of concrete for various concretegrades shall be taken as lower values in the range of valuesspecified in IS:4998 (part I) 1992.

7. The static modulus of elasticity of concrete shall be taken as under:

5000ck

F Fck for instantaneous loadings. Where Fck is the

characteristic compressive strength of concrete as per clause 6.2.3of IS:456-2000.

8. Minimum thickness of the shell shall not be less than 250 mm.

9. Reinforcement in the shell shall be provided as per IS : 4998 (Part I) 1975. However, the maximum spacing of reinforcement shallnot be more than 250 mm both ways in the shell and 300 mm forfoundation raft.



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Minimum 0.12% reinforcement shall be provided on either face andon either side of foundation.

While providing vertical reinforcement steel in the shell, the totalnumber of vertical bars shall be continued till such height whenalternative bars can be discontinued. However, reduction of bardiameter along the height is permissible. At any section of the shellvertical bars shall be uniformly spaced. Non-uniform spacing ofvertical bars is not acceptable.

One third of the vertical bars can only be lapped at one section.

10. Opening in the shell shall be provided for duct work, access doors,ash channel and ventilation system etc. The maximum width ofopening shall be limited to an angle of not more than 30osubtendedat the center of the concrete shell.

The total plan area of the opening at a particular section shall not bemore than 15% of plan area of concrete shell at that location. Theopening size for the purpose of stress calculations shall be taken as1.1times the actual width of opening. The extra reinforcementaround opening shall satisfy the requirements given in the followingdocuments and the highest shall be provided.

a) IS 4998 (Part I)

b) ACI 307

c) Reinforced concrete chimney and tower by M.G Pinfold.The value of K1 as given in the book by M.G. Pinfold onpage no. 186 shall be taken as 0.11.

Minimum half the number of extra horizontal bars in shell around theopening to continue for complete circle all round for both faces andboth sides.

11. Embedments to support the staircase shall be provided in the shell.

12. Expansion anchors shall be used to attach conduit, lighting and

protection equipment, lighting fixtures and other lightweightappurtenances.

13. Staircase and elevator enclosures shall be provided keepingprovision of an elevator electrically operated and of rack and piniontype.


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8.02.00 Liners

8.02.01 The bidders scope includes the design, supply, fabrication, installation and

testing of the steel flues with insulation and expansion compensatorsincluding spares as required. The bidders scope includes the design,preparation of detailed fabrication drawings for the steel flues fabricationand installation. It shall be the bidders responsibility to test the supports,restraint points, stiffeners, expansion joints and insulated steel flues againstvibrations and specified temperature variations. On no account will a leakyflue be permitted.

8.02.02 The lining material/stiffeners shall be fabricated from mild steel having anultimate tensile strength of not less than 410 N/Sq.mm. and conforming tothe requirement of IS:2062 (Grade-A). The minimum thickness of the linershall be 8 mm. A minimum corrosion allowance of 2 mm. shall be allowedfor arriving at the desired thickness. All steel shall be of tested quality only.

8.02.03 The portion of liner with stainless steel shall be provided with a grade ofsteel conforming with the requirements of AISI type 316 L or equivalent andthe minimum thickness of the stainless steel liner shall be 6 mm.

8.02.04 The individual cans of the liners shall be jointed together by butt weldinginternally all round for full strength, after connecting the flanged portion ofthe cans with high tensile treaded fasteners conforming to IS:1367.

8.02.05 The bidder shall test all welds in the presence of the OWNER to meet thefollowing requirements:

i) The bidder shall test at random at least 10% of the butt welds byradiographic/ultrasonic testing methods.

ii) At least 10% of the fillet welds shall be tested at random by dyepenetration tests.

iii) 10% of the root welds for butt-welding shall be tested at random bydye penetration tests.

8.02.06 All tests shall be conducted in the presence of the ENGINEER INCHARGE. If any test fails, the weld shall be cut out, remade and retestedto the ENGINEERs satisfaction.

8.02.07 Bidder shall ensure that deviations shall not exceed the specified tolerance

spelt out herein below for fabrication and erection of steel flues. Thepermissible deviations from the true form are as under :

8.02.08 Internal diameter shall not differ from the true or design diameter by morethan 20 mm. in the horizontal plane.


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8.02.09 Horizontal centre of any section shall not deviate more than 12 mm. fromthe shell vertical centre line in any 15 m. height and never more than 1500of height plus 12 mm. at any level considered.

8.02.10 Locally, the variation of the bent plates from true circular form (flat spots)should not exceed the plate thickness. All measurement/checking shall bedone by a segmental circular template having the design radius and achord length of 0.15 times the design radius.

8.02.11 At welded horizontal seams any form of packing or welding shall notexceed 4 mm. when measured with a straight edge template, long enoughto make contact with the straight portion of shell on either side of thepeaked area. Where deviations at such areas as flat spots and peakedseams exceed tolerances, stiffeners may be provided only on prior approvalof the ENGINEER.

8.02.12 Flue liners will not be painted.

8.03.00 Insulation for steel flue liner

8.03.01 The flue shall be semi-rigid insulated externally with mineral wool madefrom rock slag or fibrous glass bonded by a suitable resin binderconforming to IS: 8183 or equivalent with a maximum coefficient of thermalconductivity of 0.062 W/m deg. C at a mean temperature of 150 deg. C.

8.03.02 Two layers of insulation material each of a minimum thickness of 25mmshall be provided and all joints shall be staggered. The material shall havea minimum density of 80 kg/cum. for resin bonded glass wool insulation and100 Kg./cum. for resin bonded rock wool insulation.

8.03.03 Insulation for the exposed portion of flue at the top shall consist of 6 layersof insulation material each of a minimum thickness of 25 mm. and all jointsshall be staggered. The material shall have a minimum density of 200Kg/m3. This shall be protected by means of a stainless steel cladding,flashing and hood of grade 316 L stainless steel.

8.03.04 The bidder shall ensure that the insulation can safely withstand maximumflue gas temperature without deterioration or break down, slag wool shall beavoided, and the material shall be free from shots and other impuritieswhich may cause corrosion. The insulation should be able to withstandvibrations and should not settle down in any case, such as during transport,

storage, erection and operation and also due to its own weight. It shall notbe affected by existing flue gas acids in case of exposure.

8.03.05 The insulation shall be tightly secured to the exterior surface of the liner byimpaling them on studs welded to the surface at 450 mm c/c bothhorizontally and vertically. The studs shall be plated and be of a minimum


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thickness of 10 gauge. The studs shall extend a minimum of 25 mm.beyond the thickness of insulation and 63 mm. circular or square metalplate speed washers of standard thickness shall be placed on the extendedportion of the studs to hold the impaled insulation material well in place.

Further, a 20 gauge galvanized wire mesh with a 25 mm hexagonal patternconforming to IS:3150 shall be wrapped around. Where the wire mesh isjointed a minimum 150 mm overlap shall be provided. The mesh shall bebound and tied in place with a 16 gauge GI wire at 300 mm centres. Anyform of lacing the mesh fibres together will not be permitted.

8.03.06 The bidder at his own cost shall test the insulation material to satisfy thespecific requirements and properties as outlined in this specification IS :8183. The test shall be carried out in accordance with IS :3144.

8.03.07 The design of the steel flue shall be as per the requirement of Taskcommittee report on steel chimney liners, ASCE, New York 1975 and theinsulation shall be adequate to ensure the temperature rise in the annularspace is less than 20 deg. C above outside air temperature.

8.04.00 Expansion joints

8.04.01 The suspended portion of the steel liner shall be connected to the bottomsupported portion of the liner by an Expansion Joint shall be able tocompensate for the large thermal movements of the steel flue, be gas tight,acid resistant, heat resistant and provide an adequate insulating medium toavoid excessive overheating in the access void. The material used for thefabrication of the expansion joints shall be suitable for the flue gasconditions.

8.04.02 The expansion joints shall be made of flexible fibre. They should be tightand impermeable and should withstand the maximum serviceabletemperatures of the flue gas.

8.04.03 The bidder shall also supply spare expansion joints to suit the requirementsof this specifications, complete with instructions for storage, fitting,instructions, spare accessories, tools for installation etc. to replacefaulty/used expansion joints at a later date. The spares should withstand astorage period of not less than 10 years.

8.04.04 The bidder shall procure the units from any specialist manufacturerfabricating the type of expansion compensator. The recommended

specialist manufacturer of such expansion compensators is SCANDURALTS., P.O.BOX-18, CLECHEATION, WEST YORKSHIRE,BD 193 UJ,ENGLAND. Installation of the expansion compensators shall be strictly asper the manufacturers instructions. The manual shall indicate thesequence of installation procedure and shall be strictly adhered to onceapproved.


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8.05.00 General requirements for steel liner

8.05.01 Liner Hood/Cap for Steel Flue Chimney

The liner hood shall be designed and fabricated from 6 mm. thick stainlesssteel sheets of grade 316L. The hood shall completely cover the annulararea packed with insulation material between the stainless steel flue andcladding. This will prevent exposure of insulation to the surrounding fluegas environment. Special care should be taken to provide sufficient overlapof the stainless steel flashing cladding over the shield plate attached to thechimney roof cap. All sections of the cladding/flashing and shield plateshall be anchored in place with stainless steel bolts/nuts. Slotted holesshall be provided to make allowances for differentialexpansions/movements.

8.06.00 Interior Platforms

8.06.01 The interior platforms shall be provided at intermediate levels. Distancebetween two platforms shall not be more than 40 M. The platforms for thesteel flue chimney include a grillage of M.S. beams provided for supportingthe roof slab, supporting the flue cans, restraint platforms for flues and foraccess within the shell. Except for the roof slab, all the platforms shall beprovided with M.S. grating. The platforms shall be designed for self weightvertical/horizontal liner loads and a live load of 50 kN/m2.

8.06.02 The members of the beams grillage shall be assembled by high precisionbolted connections only. The member dimensions shall be made to suitwith the as built conditions within the wind shield. The beam grillage shallbe painted as per the requirements of IS:1477 with 2 coats of zinc rich redoxide primer and 3 coats of synthetic enamel paint of approved shade.

8.06.03 The grating shall be fabricated from M.S. flats comprising of 25 x 5 thickbearing bars spaced at 25 mm c/c and 12 x 5 thick space bar. The gratingshall be hot dip galvanized and shall be procured by the contractor.

8.06.04 The Hand railing shall be of medium quality 32 mm NB GI pipe conformingto IS 1161 in 3 rows with railing post of 40 mm NB GI pipe spaced atapproximately 1300 centre to centre. Hand railings shall be provided for allplatforms.

8.06.05 Handrails shall be provided with kick plates along the platform edges.Hand rails shall be provided at all staircase ladder access points.

8.07.00 Deleted

8.08.00 Soot Hopper


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8.08.01 Soot hopper shall be of MS and lined with acid-resistant brick work of min75 mm thick in acid-resistant mortar. Only shaped acid-resistant bricksshall be used. Laying and joining shall conform to the requirements laiddown for acid-resistant brick lining. In addition to the above an insulation

layer of minimum thickness 50 mm shall be provided on the external face ofthe hopper and suitably covered with aluminum foil of minimum thickness of1 mm.

8.08.02 The acid resistant bricks shall conform to Class I of IS:4806 and the mortarfor this brick work shall conform to IS:4832 Part-I : Silica type withpotassium silicate liquid binder. Curing of mortar joints with 25% dilute HCLshall be done for a minimum of three days and as per MANUFACTURERsrecommendation after which exposed face shall be thoroughly cleaned.

8.08.03 At the bottom of the hopper, a flanged pipe of specified diameter and lengthshall be welded. Inside of this pipe sleeve shall be coated with sodiumsilicate.

8.09.00 Flue Support Arrangement

8.09.01 The support brackets and bearing assembly shall be welded to the locallythickened portion of the flue and in turn support the flue on the supportplatform. The arrangement shall cater for thermal movements of linerelements in a smooth and easy manner.

8.09.02 The support arrangement shall typically consist of the flue support shoe(which is part of the flue), flue support bracket which is connected to theshoe by a precision bolted connection. The bracket in turn is welded to abearing assembly. The bearing assembly is later bolted to the supportbeams available.

8.09.03 The bearing assembly shall be fabricated from mild steel units with astainless steel sheet bearing plate and load bearing insulation blocks. Thisplate shall be provided with a recess to seat a PTFE film conforming toBS:5400 dimpled on the upper surface and lubricated with silicon grease.

8.09.04 Suitable restraint brackets and stop plates of MS shall be provided to avoidexcessive movement, and keep the different units of the bearing assemblyin position.

8.09.05 The insulation blocks shall be of natural grade fibre reinforced asbestos oran equivalent material which shall primarily consist of the following physical

properties :

i) Minimum compressive stress prior to onset of compression yield ofnot less than 12 N/Sq.mm. An allowable compressive stress of 4N/Sq.mm. shall be considered for sizing of bearing assembly.


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ii) Minimum shear strength of 30 N/Sq.mm. when tested in accordancewith BS:3497-1979.

iii) Thermal conductivity shall not exceed 0.67 W/m deg. C at a meantemperature of 200o C and its coeff. of linear expansion not to

exceed 1.2 x 10E-5 per deg. C.iv) Adhesive used for bonding purposes shall be of material withequivalent high temperature properties as approved by theENGINEER.

8.09.06 At flue restraint platforms, necessary restraint arrangement with loadbearing, insulation blocks and stainless steel bearing plates fixed to theinsulation blocks shall be provided.

8.09.07 Restraint and support brackets shall also be provided for the bottomsupported portion of the flue which rests on the support platform provided atthe base to cater for bearing and restraint requirements.

8.10.00 Louvers for air outlet/inlet openings

8.10.01 Air inlet and outlet louvers shall be provided as per the requirement.

8.11.00 Liner Test Ports for steel liner

8.11.01 Four gas sampling ports fabricated from SST or MS pipes as the case maybe with flanged ends shall be provided for liner at platform levels. Thesampling equipment is not in the scope of this contract. The Contractorshall, however, provide all the necessary fittings required for the port holes.The cost of these provisions shall be included providing a power connectionwith 15.5 Amps/220 V plug sockets near every port hole. The load shall be1000 Watts.

8.11.02 Bidder shall provide for the purpose of instrumentation other than thesampling ports mentioned in clause 8.8.1 above required number of 38 NBconduits including pull wires, junction boxes and pull boxes, all securelytacked/anchored to internal surface of shell and S 316 L plates below eachpipe insert for fixing of measuring instruments.

8.12.00 Stair Case for Chimney

8.12.01 A steel staircase of 900 mm clear width shall be provided internally withinthe shell from the bottom to the top to provide access to all platforms. It

shall be fabricated from MS rolled I or channel section stringers. Treadsshall be of steel grating designed for self-weight and a live load of 500Kg/m2. Treads shall be provided with an approved anti-slip nosing set flushwith the stair tread. Hand railing shall be provided for the stairs for thewhole height. The staircase shall be supported on a steel frame workindependent of shell with all members connected with suitable, bolted


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connections only. The supporting structure shall be painted as per therequirements of IS:1477 with 2 coats of zinc rich red oxide paint and 3coats synthetic enamel paint of approved shade. The steel treads shall behot dip galvanized.

8.13.00 Access door @ roof

8.13.01 One access door of size 750 mm x 1000 mm shall be provided to coveraccess opening at + 270 m floor.

8.14.00 Cleanout Doors/manholes for steel l iner

8.14.01 One pair of doors 650 x 825 mm in the lining shall be provided for cleaningsoot hoppers and for access to inside of the flue. Clean outdoors/manholes shall also be pro vided at intermediate levels.

8.14.02 The doors shall be hinged and provided with a locking device in addition toswivel studs with wing nuts on the remaining three edges at spacing notmore than 500 mm

8.15.00 Foundation

A circular raft/ pile cap foundation, preferably annular, shall be provided.The raft/ pile cap (min M25) shall be designed as rigid member with uniformthickness and no tapering of thickness shall be allowed. Minimumthickness of raft shall neither be less than 0.09 times the diameter of raftor0.3 times the overhang the foundation beyond shell, whichever is greater.Minimum reinforcement shall not be less than 0.12% in each direction.Wind and earthquake shall be treated as normal load and no enhancementof stress is permitted on this account in soil, concrete and steel. Notension will be allowed under the raft/pilecap during earthquake and wind.Working stress method shall be adopted for design of foundation.Foundation will be designed for SRSS of moments of along wind responseand across wind response.

9.00.00 SOIL DATA AND BEARING CAPACITY

All recommendations for final detail geo-technical soil investigation (to becarried out by successful bidder and approved by Owner/Consultants) areto be considered as per soil report and specifications.

10.00.00 GALVANISED STEEL STRAKES

Based on actual parameters, arrived at after detailed analysis and design,aerodynamic studies shall be carried out. The arrangement of thegalvanized steel strakes, if needed, shall be decided, based on thesestudies.


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11.00.00 OUTER PLATFORMS

11.01.00 Nos. of outer platforms to be provided are governed as per the

requirements of aviation obstruction lights which are required to beprovided at various levels so as to meet the requirements of IS: 4998 (latestedition). I.C.A.O regulations and instructions issued by the Director Generalof Civil Aviation.

11.02.00 The minimum clear width of the platforms shall be 1000 mm and a live loadof 500 kg/m2 shall be considered for their design.

11.03.00 At 270 m level platform, on upper surface 20 mm thick acid resistant tilesconforming to IS: 4457 over water proofing shall be provided, using acidresistant mortar. The average thickness of mortar bed shall be 10 mm andit shall be sloping outwards.

11.04.00 Hand railing shall be provided all around external platforms, including hoodplatform using 32 mm G.I. pipes. The spacing of railing posts shall not bemore than 2000 mm centre to centre. The height of hand railing shall not beless than 1250 mm. There shall be three handrails at about 450 mm and850 mm & 1250 mm respectively above platform level.

11.05.00 32 mm dia G.I. drainage spouts shall be provided in platforms for drainageof rain water.

11.06.00 150 mm dia MS (galvanized) RWDC pipe shall be provided to carryrainwater from Hood platform to discharge point at ground level. Thenumber of down take pipe shall be decided as per design.

12.00.00 ENCLOSURE WALLS

12.01.00 Reinforced concrete walls shall be provided at grade level around staircaseand elevator to make the enclosed space airtight and free from ash anddust for the comfort and safety of personnel who are required to go insidethe chimney for maintenance and inspection purposes.

12.02.00 All materials to be used and design of wall shall be as per relevant I.S.Codes.

13.00.00 ROLL-UP DOOR

13.01.00 A rolling steel chain operated door of size 4.0m x 5.0m shall be installed atthe base of the chimney shell as indicated on the drawings so that a truckcould go inside the chimney in case of emergency. The door shall beinstalled complete with guides hood hardware, weather baffles combination


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end locks and wind locks mechanisms and accessories, as required forproper operation and weather protection. The complete details of rollingshutter shall conform to IS: 6248 (latest edition) Metal Rolling Shutters &Rolling Girds and to these specifications.

13.02.00 The door shall be installed in accordance with the details and themanufacturers directions. When installed, the door shall be free from warptwist, or distortion and shall be lubricated and adjusted to operate freely andsmoothly.

14.00.00 PERSONNEL/ ACCESS DOORS

14.01.00 A steel personnel door of size 1200 x 2100 shall provide access to thechimney at grade level.

14.02.00 Personnel doors of size 1200 x 2100 shall be provided for access to eachairtight enclosures at grade level inside the chimney (i.e. enclosures forstaircase and elevator) and also in chimney shell at external platformslevels so that civil aviation lights mounted on these platforms could beapproached for maintenance and replacement purposes.

14.03.00 The doors shall be hinged and provided with positive locking device. Thehinges required for connecting the door with door frame shall be eitherheavy weight. Butt Hinges conforming to IS: 1341 (latest) Steel ButtHinges & Strap Hinges. The size and number of hinges required for eachdoor shall be decided as per the overall weight of the door and it shall beensured that door shall remain in its perfect position after installation underservice conditions. The minimum size of the hinges shall not be less than150 mm.

15.00.00 INSPECTION/ MAINTENANCE DOORS

15.01.00 Two steel leak proof doors of size 750 x 1000 mm and 750 x 600 mm shallbe provided diametrically opposite in each steel liner at all those levelswhere external platforms are provided.

15.02.00 Proper sealing arrangement using asbestos ropes shall be provided in thedoors so that there is no leakage of flue gases from steel flues into theannular space between liners and shell through these doors.

15.03.00 The doors shall be constructed of two outer sheets not less than 6 mm thick

mild steel reinforced inside with steel stiffeners not more than 600 mmcenters. Hollow space between two plates shall be filled up with insulatingmaterial such as bonded glass wool/ mineral wool. The doors shall behinged and shall be provided with locking device such as swivel studs withwing nuts.


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15.04.00 All surfaces of doors & frames internal as well as external shall be paintedwith one coat of primer and finish painted with two coats of acid and heatresistant paint.

16.00.00 HATCHES

16.01.00 A mild steel hatch shall be provided as an access to the hood of thechimney.

16.02.00 The hatches shall be constructed of two outer sheets not less than 3 mmthick mild steel reinforced inside with steel stiffeners not more than 600 mmcenters. In addition, they shall also be designed to withstand a live load of300 kg/m2.

16.03.00 Hatches shall be painted with one coat of primer and finish painted with twocoats of acid and heat resistant paint on both sides.

16.04.00 Other requirements with regard to design and construction shall be sameas for Personal / access doors.

16.05.00 The hatches shall be flat type and shall be operational upwards. They shallbe provided with locking arrangements from under side for the hatch forhood.

17.00.00 BEARINGS

A fully moulded elastomeric bearing shall be provided to accommodatethermal movements and to provide a suitable distribution of load betweenliner support platform beams and the platforms.

18.00.00 ELEVATOR

It is required to accommodate the elevator and staircase within theR.C.C shell having two flues for two 500 MW units.

The travel of the lift shall be up to the last but one platform which shall beabout +270 m from 0.0 m level.

19.00.00 FLUE OPENINGS AND DUCT WORK

The concrete shell at flue duct entry shall be adequately protected against

high temperature by cast able refractory lining and the gap between theshell and duct shall be properly sealed off by asbestos/or any other suitableseal.


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The openings in the windshield shall be sufficiently reinforced to withstanddesign loads. Similarly the openings in steel flues shall be properlyreinforced for receiving the flue ducts.

The R.C.C. shell shall provide support for duct work from the expansionjoint to the chimney liner.

Exposed ductwork shall be insulated and lagged to protect equipment &prevent injury to personnel. The insulation and wire mesh shall be securedto the lagging by means of pins or prongs welded to the exterior sheet andspaced on intervals not exceeding 450 mm in both the directions. Theinsulation shall be impaled over the pins or prongs, wire mesh applied overthe insulation and the insulation and mesh shall be held in place with speedclips.

20.00.00 CHIMNEY PAINTING

Painting the entire inner surface for full height as well as exposed surface ofinternal platforms and beams, internal / external surface of mini shell, all airtight enclosures with acid and heat resisting black impregnated bitumasticpaint (not less than four coats) to give a paint DFT not less than 150micron.

The entire outside surface of concrete shell shall be painted with alternatebands of signal red and white colour, out of which top 50 m shall be paintedwith acid heat resistant paint and rest of the outside surface shall bepainted with synthetic enamel paint conforming to IS: 5410 in alternatebands of red and white colour.

21.00.00 SPECIFIC CONSTRUCTION REQUIREMENTS

21.01.00 Concrete

21.01.01 Batching of concrete

For controlled concrete, only weigh batching shall be allowed. All concreteingredients, except water, shall be batched by weight, using an approvedmake of weigh batcher. Batching shall be accurate to 1/2 Kg. The batchershall be tested for accuracy of calibration, first before commencement ofwork and at least once a fortnight or as directed by the Engineer thereafter.

Water shall be batched by weight or by volume measures, as approved bythe Engineer.

21.01.02 Construction Joints


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In concreting the chimney shell one full ring lift shall be completed in aday's pour. Before the formwork for the following pour starts the horizontalsurface of the Chimney shell shall be chipped, cleaned and washed withwater, and when the formwork is complete, the surface shall be cleaned

and washed again and covered with 1:2 sand cement slurry before freshconcrete is placed. The horizontal construction joints shall be so arrangedand made that they are regular and neat. No vertical joint shall be allowed.No separate payment shall be allowed to the Contractor for forming joints orchipping and cleaning them or cover with slurry prior to concreting. Thenumber of construction joint shall be kept minimum and the spacing shouldnot exceed three (3) meters. The Contractor shall submit to the Engineer,any proposal of providing construction joints to facilitate his work, for thestudy and approval of the Engineer well in advance.

21.02.00 Construction by Slip-Form Method

21.02.01 Slip Form

The RCC shell of the chimney shall be constructed by using slip formtechnique. The slip form shall consist of a central ring and tower system.Normally the slip form shall be of radial beam system having two levels ofbeams, upper and lower level beams, radiating out from the central ringbeams to the slip form yokes equally spaced around the circumference ofthe structural wall.

The lower beams shall be made up of hand able standard unit trussesbolted together to make up the required start diameter. To accommodatethe wall taper the beams are shortened by removing units as the slideproceeds.

The bottom beams shall be further supported by under trussing. A RadialControl gear by which the radius of the concrete shell is controlled shall beattached to the outer ends of the upper and lower beams. This shall beactivated automatically or manually linked to the upward movement. Theslip form shall preferably have at least two working platforms at lower radialbeam level as a main working deck and for access to the hoist cage and atthe upper radial beam level as a control point for the radial and batteradjustments at the yoke positions.

Access to the shutters and to the concrete surface shall be provided by acircular platform under the lower radial beam for the inner surface and by a

three level circular platform supported from the outer yoke post for the outersurface.

A special safety net consisting of man carrying mesh with a smaller meshfor materials shall be provided to envelope both the outer platforms and theinner hung platform.


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Shuttering shall be of standard lap sheets hung from high tensile steel rodwalers, threaded through holes drilled in the yoke posts.

Steel embedment, chases and openings as per approved drawings shall befixed or formed in the shell where steel frames are used for openings, theyshall be rigid, reassembled and fixed in position. For small openingswooden frames may be used.

The spacing of jack rods, shall not be more than 1 m or as approved byEngineer. The jack rods shall be left (no retrieval of jack rods is allowed) inconcrete and they shall not be figures as reinforcement.

Jacks used in Hydraulic Jacking system for slip form shall conform torelevant Indian Standards.

An accurate height measure shall be installed.

The Contractor shall furnish with his bid complete details and literature ofthe slip form he proposes to use for the concreting of the shell.

The Contractor shall be responsible for the safe operation of the slip formand the safety of the labour, supervisory staff, others during the concretingof the shell by providing hand railing around the platforms, lighting (500 to1000 lamps with reflectors shall be provided, fixed on scaffold tubesattached to the yokes, 3m to 4.5 m above the working deck and 4.5m to 6m apart), Intercom arrangement, etc. In case of power failure, batteryoperated emergency lights on working deck shall be provided.

The Contractor shall also provide all arrangements like hoists, winches,chutes etc. required for the transport of the materials to the workingplatforms.

Ambient temperature and the resultant impact on the concrete temperatureat the time of placement shall be taken into account while deciding thespeed of the slip form. If slip forming is to be carried out in summer, (May toSeptember) slip-forming speeds up to 250 mm per hour may be used. Incase lesser values are contemplated, retarders conforming to relevantIndian Standard Codes and approved by the Engineer shall be used.

The Contractor shall ensure, that no dragging of concrete with the upward

movement of the slip form shall occur. Twisting in the horizontal plane ofthe slip form assembly and tilting. In the vertical plane of the slip formassembly shall not be allowed. The Contractor shall be responsible for anysuch occurrences and he shall have to make good for these as per thedirections of the Engineer at no extra cost.


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The minimum compressive strength of concrete immediately below thebottom of the form panel as the slip form proceeds shall under nocircumstances be less than 1.5 kg/ cm2.

The Contractor shall submit to the Consultant / Owner with two monthsafter the award of the work a construction methods statement indicating thefollowing in his statement:

a) Description of equipment for slip forming and for concretingoperation.

b) Structural analysis regarding the adequacy of slip form equipment.

c) Standby arrangements for equipment.

d) Requirement of quantity of materials for each stage of construction.

e) Planned manpower for operation and supervision.

f) Planned rate of slip forming and details of concrete mix.

g) Planned interruptions.

h) Description and frequency of dimensional and verticality checks.

i) Description and frequency of tests for concrete and raw materials.

j) Methods of preparing, transporting, pouring and vibrating andfinishing concrete.

k) Contingency solutions for rectification of probable defects during slipforming.

l) Plan of operation during planned interruptions including retrieval ofjack rods, resetting of from panels etc.

21.02.02 Tolerances:

The permissible tolerances should be as per IS specification

21.02.03 Precision instruments using laser beams (minimum 2 nos.) shall be used

for maintaining the formwork in required axis and for carrying out variouschecks.

21.02.04 Precision instruments like optical plummet to monitor the tilt and twist in thevertical plane and horizontal plane respectively shall also be provided.


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21.02.05 Sufficient anchorage shall be provided for the slip form structures in theinitial stages of work against wind pressure till the jack rods are embeddedenough to take grip.

21.03.00 Chimney Steel and Metal Work

All workmanship shall be of best practice in modern structural shops, andshall conform to the provisions of the IS:800 and other relevant ISSpecifications, unless otherwise specified.

21.04.00 Painting

The metal surfaces, which are to be painted, shall be prepared properly asstated elsewhere in the specification.

All paints shall be of make and shade as instructed and approved by theEngineer. Necessary test certificates, manufacturer's literature and samplesshall be submitted to the Engineer, for his approval, before bulk purchase ismade.

21.05.00 Galvanizing

All steel including threaded bolts, nuts and washers, unless specifiedotherwise in contract, shall be hot dip galvanized in accordance with ISSpecification or American Society for Testing and Material SpecificationASTM 123.

All members to be galvanized shall be cleaned thoroughly, to thesatisfaction of the Engineer, by the process of pickling. Pickling shall becarried out in an acid bath containing sulphuric or hydrochloric acid ofsuitable and adjusted concentration and temperature. Pickling process shallbe completed by rinsing the members thoroughly in warm water.

Galvanizing shall be carried out by hot dip process in a proper anduniformly heated bath and it shall meet all the requirements when tested inaccordance with IS: 2633. The zinc coating shall be of uniform thicknesswith an acceptable minimum value of 610 gms/m2for structural steel. If thegalvanizing of any member is damaged, the Engineer shall be shown of theextent of damage and if so directed, the galvanizing may have to be redonein the similar manner stated above.

21.06.00 Erection

Erection of structural members and C.I. Chimney caps shall be done as perrequirement of IS: 800. The Contractor shall submit to the Engineer aprogramme of erection for his approval. All plant, equipment, tools, tackleand any other accessories required for the erection shall be provided by the


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Contractor. Storing and handling of fabricated materials for erection, settingout of members, providing temporary supports, bracing, fasteners, bolts,nuts etc. shall be the responsibility of the Contractor and shall be taken intoaccount in quoting the rate.

21.07.00 Cast Iron Cap

The Cast Iron cap, fitted at the top of the chimney, shall be of thickness notless than 12 mm. This shall preferably be a single cap covering both theconcrete shell and the lining, with the segments bolted together securelyand properly anchored inside the concrete in such a manner as to form acomplete annular unit, allowing for unequal circumferential and verticalexpansion and contraction of concrete shell and lining and for deflection ofshaft due to wind.

All bolts, nuts, washers, rag bolts and other fasteners as required for fixingcast iron cap shall be of bronze material. Gaps between segments are to befilled with asbestos mill-board or fibre-glass packing. Casting is to beassembled to match with the dimensions specified in drawings, beforedespatch to site. C.I caps to be painted with two coats of Acid ResistingPaints over primer coats as recommended by paint manufacturer.

21.08.00 Insulation and Packing

All packing and insulation material shall be of thickness, diameter and type,shown in the drawing. The packing and insulating material shall be made ofasbestos rope, vermiculite concrete, slag or mineral wool and asbestos mill-boards.

a) Asbestos Rope

The diameter of the rope shall be as per drawing. The material shall beof best quality available in the market and shall be purchased after asample is approved by the Engineer. The rope shall be plain, Grade-I,conforming to IS: 4687-1968. The strand shall be long, well twisted andno torn thread shall stick out. The rope shall be firmly packed so as toprevent gas leakage.

b) Slag or mineral wool

The thickness of packed slag wool shall be as shown in the drawing.The packed density of the wool shall be within the range of 175 to 200Kg./m3 and the co-efficient of thermal conductivity shall be within therange of 0.025 to 0.035 Kilo Calories/hour metre oC at a mean


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Two numbers of vertical down conductors of 50 x 6 mm. galvanized steelflats shall be provided, spaced as shown in drawings. The down conductorsshall start from the top encircling band, leading to the ground. Galvanized

steel 50 x 6 mm. flat bands shall be provided below each balcony.Encircling band, below each balcony, shall be electrically connected toeach down conductor. The connections of the galvanized steel downconductors to the copper air terminals shall be brazed and connection tothe nearest grounding grid at the bottom shall be arc welded. Connectionbetween any two galvanized steel flats/bands shall be made by arc welding.

The galvanized steel flat encircling bands shall be supported at an intervalof maximum 600 mm. and the vertical down conductors shall be supportedat an interval of approx. 2500 mm. The fasteners shall be of same grade ofmaterial as the conductors and have to be galvanized. The conductor shallbe laid straight and sharp bends shall be avoided as far as practicable. Asuitable bolted test piece shall be provided at each down conductor at aconvenient height near the bottom of the chimney.

At All supports, the portion embedded inside the chimney shell concreteshall not touch the reinforcement bars and shall be duly insulated fromthem.

21.09.04 Bonding

All exposed metallic parts of the chimney shall be bonded to the downconductors. Such parts shall include ladders, balconies, conduits, etc. If themetal has considerable length, it shall be bonded at each end. If themetallic components are composed of electrically discontinuous parts, eachpart shall be bonded to the down conductors. The bond shall have aminimum cross sectional area equal to that of the down conductor.

21.09.05 Joints

The joints in the lightning conductors shall be kept to a minimum and thereshall be no joint in the underground portions of conductors. All joints, exceptthose for the air terminals, shall be done by arc welding process.Overlapping of the conductors at straight joints shall not be less than 150mm. The bolted joint of the test piece shall be covered with thick coating ofbituminous paint after successful testing. The connections between theM.S. down conductors/short piece (of 50 x 6 mm. galvanized steel flat) and

the copper air terminals shall be brass brazed as shown in the drawing(with the help of brass rods, manufactured by Indian Oxygen Limited (Silosor Ruptum 14) or equivalent.

21.10.00 Aviat ion Obstruct ion Lighting System


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conduit knockouts for incoming and outgoing conduits. 4-core PVCinsulated cable with Aluminium Conductor will be used to feed powersupply to the bottom most junction box which shall have suitable doublecompression type cable gland for erection and installation of cables.

21.10.05 Painting and Lead Coating

All welded joints with galvanized steel shall be provided with coldgalvanizing paint. Other accessories necessary for lightning protection aswell as brackets, supports and other items of obstruction lightinginstallations, shall be painted with two coats of Red Oxide priming paint andone coat of Aluminium finishing paint. The Red Oxide paint shall be appliedon the down conductors and bands before installation and the Aluminiumpaint coating shall be applied after the installation is over. The copper airterminals, conductors, fasteners and other accessories upto the topencircling band shall have a continuous lead covering of about 2 mm.thickness, for protection against corrosion due to gases and weather.

21.10.06 Temporary Obstruction Lights

The Contractor shall provide at least two (2) lights located at diametricallyopposite points at the top of the chimney during the period of constructiontill the permanent obstruction lights are installed and energised, to serve astemporary obstruction lighting.

21.11.00 Information to be Submitted

21.11.01 After Award

The following information and data including samples where necessary,shall be submitted by the Contractor, progressively during the execution ofthe Contract.

21.11.02 Design Mix

Design mix as per details of this specification giving proportions ofingredients, sources of aggregates and cement along with accompanyingtest results of trial mixes as per relevant IS Specifications shall be

submitted to the Engineer, for his approval, before it can be used on thework.


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21.11.03 Detail Drawings

Following items shall be provided by the Contractor, which are to beapproved by the Owner.

a) Detail drawings and designs of formwork including scaffolding to beused. If slip form method of construction is adopted, then detaildrawings showing all the arrangements for slip form technique includingmethods for reducing internal diameter and providing required slopes onouter diameter.

b) Detail drawings and bar bending schedules for concrete components.

c) Shop drawings for steel and metal work, including inserts etc.

d) Detail drawings for templates and temporary supports for embedments.

Documents

Annexure-III Chimney Spec[1]