Appendix-8 Painting Specification

7/25/2019 Appendix-8 Painting Specification

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PROJECT : Kudgi Super Thermal Power Pro ject Stage I ( 3X800 MW )

Doc. Name Painting Specification

Doc. No. Appendix-8 Issue A Page 1 of 12

Corrosion Protection / Painting / Color coated sheets

General

(a) All equipments, pipes, etc. shall be painted as per the requirements specified in the relevant

section of the specification.

(b) All Steel structures (except those embedded in Concrete) shall be provided with Painting as

given below which is designed for a minimum maintenance free life of Ten (10) years (expected

life, long range Ten (10) to Twenty (20) years, as per BS: 5493.

(c) All Paints shall be of high build constitution.

(d) All Painting shall be done as per approved Painting scheme of the Vendors / Manufacturers,

which shall be submitted by the Bidder and as approved by the Employer. Painting scheme shall

also include Item codification / Description of all Coats of Paints for manufacturers, from whom the

Paint is intended to be procured.

Painting of Steel Surfaces embedded in Concrete.

(a) For the portion of Steel surfaces embedded in Concrete, the surface shall be prepared by

Manual Cleaning and provided with Primer Coat of Chlorinated Rubber based Zinc Phosphate

Primer of Minimum 50 Micron Dry Film Thickness (DFT).

(b) All threaded and other surfaces of foundation bolts and its materials, insulation pins, Anchor

channels, sleeves, etc. shall be coated with temporary rust preventive fluid and during execution of

civil works, the dried film of coating shall be removed using organic solvents.

Painting of Steel Surfaces (other than those embedded in Concrete)

(a) All Steel surfaces shall be provided with self curing Inorganic Zinc Silicate Primer Coat (Solid by

Volume Minimum 60%) of Minimum 75 Micron Dry Film Thickness (DFT) applied over blast

cleaned surface to near white metal conforming to Sa 2 finish of Swedish standard SIS-05-5900.

The Primer Coat shall be applied in Shop immediately after blast cleaning by Airless spray

technique.

(b.) Primer Coat shall be followed with the application of Intermediate Coat of Polyamide Cured

pigmented Titanium Dioxide (TiO2) or Micaceous Iron Oxide (MIO) Epoxy based Paint (Solid by

Volume Minimum 60%) of Minimum 75 Micron DFT. This Coat shall be applied in Shop after an

interval of Minimum overnight (from the application of Primer Coat) by Airless spray technique.

(c) Intermediate Coat shall be followed with the application of Finish Coat of Polyamide Cured

colour pigmented Epoxy based Paint (Solid by Volume Minimum 60%) of Minimum 75 Micron DFT.

This Coat shall be applied after an interval of Minimum overnight and maximum indefinite (from the

application of Intermediate Coat) either before Erection by Airless spray technique or after Erection

by brush and / or spray. Colour and shade of the Coat shall be as approved by the Employer. The


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Finish Coat thickness of 75 Micron can be built up either in Single application at Shop or in two

applications one at Shop and the other at Site.

(d) Finish Coat shall be followed with the application of Final Finish Coat of Polyurethane based

colour pigmented Paint (Solid by Volume Minimum 40%) of Minimum 25 Micron DFT. This Coat

shall be applied within Seven (7) days (from the completion of Finish Coat), after Erection by brush

and / or spray. Colour and shade of the Coat shall be as approved by the Employer.

Touch-up Painting on damaged areas

(a) For Coatings damaged up to metal surface

Surface preparation shall be carried out by Manual Cleaning. Minimum 6 inches adjoining area with

existing Coating shall be roughened by Wire brushing, emery paper rubbing etc., for best adhesion

of patch Primer. Primer Coat of self-priming Epoxy Touch-up Primer applied by brush immediately

after the surface preparation. (Minimum DFT 100 Microns). Over this Primer Coat, Intermediate

Coat, Finish Coat and Final Finish Coat shall be applied as covered above by brush with

Intermediate Coat applied within maximum seven (7) days of application of touch up Primer.

(b) For Coatings damaged upto Intermediate Coatings (i.e. where Primer Coat is intact). Damaged

area including Minimum 6 inches adjoining area with existing Coating should be roughened by wire

brushing, emery paper rubbing etc., for best adhesion of patch Primer without damaging the Primer

Coat. Touch-up Primer, Intermediate, Finish and Final Finish Coats shall be applied as specified

above for Coatings damaged up to metal surface.

Painting of Welded areas / Painting of areas exposed after removal of temporary supports / Touch-

up Painting on damaged areas of Employers Structures, where inter-connection, Welding /

modification etc. has been carried out by the Contractor.

(a) Clean the surface to remove flux spatters and loose rust, loose Coatings in the adjoining areas

of Weld seams by wire brush and emery paper.

(b) Painting procedure to be followed as mentioned above for Touch-up Painting on damaged

areas.

Dry film thickness of each coat shall be checked and measured as per the procedure specified in

paint application standard no. 2 by SSPC: The Society for Protective Coating. The thickness as

measured shall not be less than the minimum thickness specified for the coat of paint under

relevant clauses of technical specification.

Coating for Mild Steel parts in contact with Water.

(a) All mild Steel parts coming in contact with water or water vapour shall be hot dip galvanised.

The Minimum Coating of Zinc shall be 610 Gms / Sq. M. for galvanized Structures and shall comply

with IS : 4759 and other relevant Codes. Galvanising shall be checked and tested in accordance

with IS : 2629.


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GratingsAll gratings shall be blast cleaned to Sa 2 finish of Swedish standard SIS-05-5900 or cleaned by

acid pickling and shall be hot dip galvanised at the rate of 610 Gms / Sq. M.

Hand Railings and Ladders

All handrails and ladders shall be galvanised at the rate of 610 Gms / Sq. as per IS : 4736.

Sea Worthiness

All Steel Sections and fabricated Structures, which are required to be transported on sea, shall be

provided with anti corrosive Paint before shipment to take care of sea worthiness.

Hand Railing

Minimum 1000 mm high hand railing shall be provided around all Openings, projections / balconies,

walkways, platforms, Steel Stairs, etc., All handrails and ladder Pipes shall be 32 mm nominal bore

MS Pipes (medium class).

Handrails shall have top and middle rails at a height of 1000 mm and 500 mm and the vertical post

spacing shall not exceed 1.50 M, with provision of kick Plates (100 mm high and 6 mm thick).

Grating

All gratings shall be Electro-forged type. Minimum thickness of the grating shall be 40 mm for in

door installation and 32 mm for outdoor installation.

The Opening size shall not be more than 30 mm X 100 mm. The Minimum thickness of the main

bearing bar shall be 5 mm.

Cutting of gratings shall not be carried out at Site. Any cutting of gratings required to provide

passage for Columns / Pipes / Cables / Ducts etc shall be done by the Contractor in Shop and cut

edges of Grating shall be suitably reinforced with binding strips.

Fire Exits

All fire exits shall be Painted with P O Red / signal Red colour shade, which shall not be used

anywhere except to indicate the emergency or safety measures. Fire safety norms shall befollowed as per National Building Code and requirements of various statutory bodies shall be

followed for providing Fire Exits, Escape Stairs and Fire Fighting Equipment.

Opening

Details / Data of all Openings required by the Contractor in Floors / Walls / Cladding / Roof to be

provided by the Employer shall be given by the Contractor, who shall also furnish all Foundation

Loads to be considered by the Employer for the Design of Foundations to support the Contractor's


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Structures / Equipment. Accordingly, the same shall be listed in Engineering Information Flow

Schedule to be furnished by the Contractor.

If the details / data of all Openings required by the Contractor in Floors / Walls / Cladding / Roof are

not furnished by the Contractor, as per the Engineering Information Flow Schedule then all such

required Openings shall be created by the Contractor himself, at a later date in Floors / Walls /

Cladding / Roof by using special tools, as required. In this case edge protection to the Openings

shall also be provided by the Contractor using Anchor Fasteners.

For routing of Pipes / Cables / Ducts, Employer shall only provide suitable passage / Opening in

Floors / Walls / Cladding. Any Pipe sleeves or embedments required by the Contractor in these

passages / Openings shall be provided by the Contractor himself. These passage / Openings shall

be suitably sealed by the Contractor after completion of Erection works.

Grouting

Non-shrink cementitious flowable grout shall be used for Grouting of pockets and underpinning

work below Base Plate of columns. Nominal thickness of grout shall be 50 mm. Nonshrink cum

plasticizer admixture shall be added in the grout. Crushing Strength of the grout shall generally be

one grade higher than that of the base Concrete. Minimum grade of grout shall be M30.

However, for Equipment Foundations, high Strength (Minimum Characteristic CompressiveStrength of 60 N / mm2 at 28 days) ready mixed non-shrink, Chloride free, Cement based, free

flowing, non-metallic grout as recommended by Equipment manufacturer shall be used. The ready

mix grout shall be of reputed make as approved by the Employer.

The surface to be grouted shall be properly cleaned by using compressed air. Contractor shall

provide the required shim plates.

Color coated and other sheeting w ork

For floor/roof decking, troughed permanently colour coated metal decking sheet, shall conform to

any one of the following

(i) of steel with zinc coated to class Z275 with minimum bare metal thickness ( i.e. excluding the

thickness of coating and painting) of 0.8mm of grade G250 as per AS1397 / grade SS255 as per

ASTM A653M / grade S250GD as per EN 10326.

(ii) of steel with zinc coated to class Z275 with minimum bare metal thickness ( i.e. excluding the

thickness of coating and painting) of 0.6mm of grade G350 as per AS1397 / grade SS340 class 4

as per ASTM A653M / grade S350GD as per EN 10326 / grade G550 as per AS1397 / grade

SS550 as per ASTM A653M / grade S550GD as per EN 10326.


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For roofing & side cladding, troughed permanently colour coated sheets (internal or external)

shall conform to any one of the following

(i) of steel with zinc coated to class Z275 with minimum bare metal thickness (i.e. excluding the

thickness of coating and painting) of 0.6mm of grade G250 as per AS1397 / grade SS255 as per

ASTM A653M / grade S250GD as per EN 10326.

(ii) of steel with aluminium-zinc alloy coated to class AZ150 with minimum bare metal thickness (i.e.

excluding the thickness of coating and painting) of 0.5mm of grade G350 as per AS1397 / grade

SS340 class 4 as per ASTM A792M / grade S350GD as per EN 10326.

(iii) of steel with aluminium-zinc alloy coated to class AZ150 with minimum bare metal thickness

(i.e. excluding the thickness of coating and painting) of 0.4mm of grade G550 as per AS1397 /

grade SS550 as per ASTM A792M / grade S550GD as per EN 10326.

Steel shall be colour coated with total coating thickness of 35 microns (nominal) dry film thickness

(DFT) comprising of Silicon Modified Polyester paint (SMP with silicon content of 30% to 50%) or

Polyester paint, of 20 microns (nominal) SMP or polyester paint on one side (exposed side) over 5

micron (nominal) primer coat and 5 micron (nominal) SMP or Polyester paint over 5 micron

(nominal) primer coat on other side,(SMP and Polyester paint shall conform to Product type 4 of

AS/ANZ 2728. Coated surface shall be provided with a protected guard film (polyethylene) of about

40 microns to avoid any damage to the coating during handling.

Sheet shall be of approved profile, sectional properties, colour and shade.

Chemical composition of troughed permanently colour coated metal decking sheets and metal

sheet for roofing and side cladding, shall conform to the provisions of the same reference code to

which the mechanical properties conform to. Mechanical properties shall be confirmed by relevant

tests.

Tolerance on minimum BMT (bare metal thickness) shall be (-)0.00mm and (+)0.06mm.

Plain permanently colour coated steel metal sheets for ridge and hips, flashings, trimmings, closure

for vertical and horizontal joints, capping etc shall confirm to the same requirements as those of

troughed permanently colour coated metal sheet for roofing and side cladding.

For metal decking the sectional modulus and moment of inertia of troughed profile per meter width

shall be so as to limit the deflection of sheets to span/250 for two span condition. The sectional

modulus and moment of inertia of troughed profile shall be computed as per the provisions of

IS:801 for satisfying the deflection and strength requirements.


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For metal roofing and side cladding, the sectional modulus and moment of inertia of troughed

profile per metre width shall be such that the deflection of sheets is limited to span/250 for two span

condition. The sectional modulus and moment of inertia of troughed profile shall be computed as

per the provisions of IS: 801 for satisfying the deflection and strength requirements. No increase in

allowable stress is permissible under wind load condition.

Maximum spacing of the fasteners shall be 390 mm c/c along the length of purlins / runners.

However exact spacing shall be as per the design done by the bidder for the fasteners considering

the wind load, self load and other associated loads. Minimum diameter of the fastener shall be 5.5

mm and atleast 3 nos. of fasteners shall be used per sheet.

Sealant used for cladding shall be butyl based, two parts poly sulphide or equivalent approved,

non-staining material and shall be flexible enough not to interface with fit of the sheets.

Filler blocks as a trough filler shall be used to seal cavities formed between the profiled sheet and

the support or flashing. The filler blocks shall be manufactured from black synthetic rubber or any

other material approved by the Engineer.

For insulation of cladding, mineral wool conforming to IS: 8183 shall be used. The density shall be

32 or 48 kg. /cu. m. for glass or rock wool respectively. The nominal thickness of insulation shall be

50mm. Special coated fasteners shall be used conforming to corrosion resistant class 3 as per

AS3566 and shall be tested to 1000 hours salt spray test.

The dimensional tolerances of profiled sheets for sheet length, sheet cover width, straightness,

squareness, depth of profile, radius and angle of curved sheets, ripple of side lap, etc. shall be as

per Manufacturing tolerances for profiled metal roof and wall cladding & roofing by The Metal

Cladding & Roofing Manufacturers Association Limited, UK.

Sheets shall be laid with a minimum overlap of 15 cm at the ends and side laps shall be of one

trough length subject to a minimum of 50 mm, having a proper water tight arrangement. The

minimum lap of sheets with ridges, hips and valleys shall be 15 cm measured at right angles to the

line of the ridge, hip and valley respectively.

Metal decking sheets shall be laid over the supporting purlins with a minimum bearing of 50 mm

and end projection of 75 mm at lap joints.


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Flashings, cappings, trimming, closure for vertical/horizontal joints, ridge and hips etc. shall be

provided with a minimum lap of 15 cm. The lapping of sheets shall provide the dust free, airtight

enclosure. If required, this may be achieved by using 2-parts polysulphide sealing compound or

butyl tape.

Distorted, blemished or water stained sheets shall not be used. Side and end laps of the sheets

shall be made weather proof by securing them with the fasteners not less than 4.8mm dia with 2.0

mm thick neoprene washer. Maximum spacing of the fasteners should not exceed 500 mm.

Precautions shall be taken during the erection of the sheets to ensure that partially erected sheets

are protected from damage at all times and particularly during inclement weather. Sheets shall be

laid over the supporting purlins with a minimum bearing of 50 mm and end projection of 75 mm at

lap joints.

Steam generator roof (Penthouse)/Canopy/Side cladding shall have single skin troughed profile

permanently colour coated sheets.

Cladding for Boiler elevator enclosure except its machine room shall be with Single skin troughed

profile permanently colour coated sheets.

Side cladding for Mill Bunker building, Transfer points & conveyor galleries (including roof) shall

have single skin troughed profile permanently colour coated sheets. However, roof of Mill bunker

building and transfer points shall be provided with troughed profile permanently colour coated sheet

on outside and plain permanently coated sheet on inside with 50mm thick mineral wool insulation in

between the two sheets.

The polycarbonate sheet to be used for cladding and glazing purpose in conveyor galleries shall

have toughed profile to match with the metal cladding profile. Minimum 2.0mm thick fire retardantand UV resistant polycarbonate clean sheet of GE plastic or equivalent approved make shall be

used. The polycarbonate sheet shall be installed along with the metal cladding so as to have a

watertight lapping arrangement. Suitable detailing shall be made to cater for the thermal expansion.

IS: 14434 to be referred for other details.

Polycarbonate sheet minimum 6mm thick multi (twin) wall fire retardant (Continuous use under

temperature 100C), impact resistant and ultraviolet resistant sheet shall be provided (as glazing)

in transfer houses, pump houses, etc.


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Paints and Painting - GeneralThe Contractor's scope of works includes supply of paints and painting of all equipments and

structures as per the Employer's standard colour coding scheme which shall be furnished to the

Contractor during detail engineering stage. The painting of various components shall comply with

the requirements stipulated in different part of this specification. However, for components where

no specific requirement is stipulated, the painting confirming to the requirements stipulated below

shall be provided.

(a) The surfaces which have surface temperature 95oC or less and which are insulated, shall be

painted with at least two coats of zinc phosphate primer as per IS 12744 & two coats of enamel

paint with total DFT not less than 80 microns.

(b) All surfaces having temperature above 95 oC and which are insulated shall be applied with at

least two coats of high temperature special primer / paint with total DFT not less than 40 microns.

(c) SG membrane walls and other Flue gas swept pressure part surfaces shall be applied with

appropriate primer for protection of surfaces during transit, storage and erection.

(d) Painting specification for all other exposed steel surfaces not covered above shall be same as

that given for corrosion protection of steel structures.

PAINTING FOR ELECTRICAL EQUIPMENTThe painting of all electrical equipment shall be epoxy based with suitable additives. The thickness

of finish coat shall be minimum 50 microns (minimum total DFT shall be 100 microns). However in

case electrostatic process of painting is offered for any electrical equipment, minimum paint

thickness of 50 microns shall be acceptable for finish coat. The Contractor shall furnish the

complete painting details during detailed engineering stage.

SPECIFICATION FOR SURFACE PREPARATION & PAINTING

Surface preparation methods and paint/primer materials shall be of the type specified herein. If the

contractor desires to use any paint/primer materials other than that specified, specific approval

shall be obtained by the contractor in writing from the employer for using the substitute material.

All paints shall be delivered to job site in manufacturers sealed containers. Each container shall be

labelled by the manufacturer with the manuacturers name, type of paint, batch number and colour.

Unless specified otherwise, paint shall not be applied to surfaces of insulation, surfaces of stainless

steel/nickel/ copper/brass/ monel/ aluminum/ hastelloy/lead/ galvanized steel items, valve stem,

pump rods, shafts, gauges, bearing and contact surfaces, lined or clad surfaces.


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All pipelines shall be Colour coded for identification as per the NTPC Colour-coding scheme, which

will be furnished to the contractor during detailed engineering..

SURFACE PREPARATION

All surfaces to be painted shall be thoroughly cleaned of oil, grease and other foreign matter.

Surfaces shall be free of moisture and contamination from chemicals and solvents.

The following surface schemes are envisaged here. Depending upon requirement any one or a

combination of these schemes may be used for surface preparation before application of primer.

SP1 Solvent cleaning

SP2 Application of rust converter (Ruskil or equivalent grade)

SP3 Power tool cleaning

SP4 Shot blasting (shot blasting shall be used as surface preparation method for hot worked pipes

prior to application of primer)

SP4* Shot blast cleaning/ abrasive blast cleaning to SA21/2 (near white metal) 35-50 microns

SP5 Phosphating

SP6 Emery sheet cleaning/Manual wire brush cleaning.

APPLICATION OF PRIMER/PAINT

The paint/primer manuacturers instructions covering thinning, mixing, method of application,

handling and drying time shall be strictly followed and considered as part of this specification. The

Dry film thickness (DFT) of primer/paint shall be as specified herein.

Surfaces prepared as per the surface preparation scheme indicated herein shall be applied with

primer paint within 6 hours after preparation of surfaces.

Where primer coat has been applied in the shop, the primer coat shall be carefully examined,

cleaned and spot primed with one coat of the primer before applying intermediate and finish coats.

When the primer coat has not been applied in the shop, primer coat shall be applied by brushing,

rolling or spraying on the same day as the surface is prepared. Primer coat shall be applied prior to

intermediate and finish coats.


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Steel surfaces that will be concealed by building walls shall be primed and finish painted before the

floor is erected. Tops of structural steel members that will be covered by grating shall be primed

and finish painted before the grating is permanently secured.

Following are the Primer/painting schemes envisaged herein:

PS3 - Zinc Chrome Primer (Alkyd base) by brush/Spray to IS104.

PS3* - Zinc Chrome primer (Alkyd base) by dip coat.

PS4 - Synthetic Enamel (long oil alkyd) to IS2932.

PS5 - Red oxide zinc phosphate to IS-12744.

PS9 - Aluminum paint to IS 2339.

PS9* - Heat resistant Aluminum paint to IS-13183 Gr.-I (for temperature 400 oC - 600 oC) , IS-

13183 Gr.-II (for temperature 200 oC - 400 oC) and IS-13183 Gr.-III (for temperature upto 200 oC)

PS13 - Rust preventive fluid by spray, dip or brush.

PS14 - weldable primer-Deoxaluminate or equivalent.

PS16 - High Build Epoxy CDC mastic `15 .

PS17 - Aliphatic Acrylic Polyurethane CDE134 ,%V=40.0(min.)

PS18 - Epoxy based TiO2 pigmented coat

PS19 - Epoxy based Zinc phosphate primer (92% zinc in dry film (min.), %VS=35.0(min.).

PS20 - Epoxy based finish paint.

All weld edge preparation for site welding shall be applied with one coat of weldable primer.

For internal protection of pipes/tubes, VCI pellets shall be used at both ends after sponge testing

and ends capped. VCI pellets shall not be used for SS components and composite assemblies.


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Documents

Appendix-8 Painting Specification