963L&T Hyderabadwp

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Release Date:17-Dec-08 Ref: RV/963L&Twp/Rev01

Standard Working ProcedureIntergard 251/Interchar 963/Interthane 990 –System L&T,ICICI IT Park Project,Hyderabad

STEELWORK PREPARATION

To provide a surface which will ensure optimum fire protection performance, preparation is required to remove surfaces which have a sharp edge. These include, but are not limited to, plate edges, weld spatter, plate laminations, weld undercuts, or gas cut surfaces.

SURFACE PREPARATION:

• Oil or grease, salts, dirts, chalk marks and similar contaminants shall be removed as far as possible, prior to surface preparation, using an appropriate method in accordance with ISO 12944-4.

• Sharp Edges, weld spatter, cavities and deformations are to be removed in accordance with ISO 8501-3, table-3

• Assess the steel surface for Rust grades as per ISO 8501-1

• Surface shall be cleaned by abrasive blast cleaning (ISO 12944-4 Cl.6.2.3.1.2) in accordance with ISO 8504-2 (Cl. 5.1.2)

• Surface cleanliness shall be as per Sa2.5 in accordance with ISO 8501-1

• Surface profile shall be 50-60 microns as per ISO 8503-4

Compressed Air

• Air used for blasting must be clean, oil free and dry. Moisture and Oil separators have to be used to ensure the same.

• The pressure should be at least 7kg per cm2 (100lbs per inch2) at the nozzle.

Abrasive

• Abrasive used for blasting should be dry and free from dirt, oil, grease or contamination and have content of water soluble matter not exceeding 0.05%.

• The abrasive must be capable of producing the standard of cleanliness and surface profile specified. (Sa2.5 and profile of 50-60 microns)

• Abrasives like copper slag should not be recycled more than once, and should not be contaminated with soil.

• Abrasive like sand should not be recycled.

Cleaning

• Before initial blast inspection, the bulk of the spent abrasive should be removed. Any substandard areas should be identified and repaired. All marking paint, chalk etc., must be removed after rectification.

• Fabrication repair (if any) should be carried out before application of the primer. Following inspection of the blast profile and standard, remaining traces of abrasive and dust should be removed from all areas.

PAINT APPLICATION

Weather Conditions

• Surfaces to be coated must have a temperature at least 3ºC (5ºF) above the dew point, immediately following blasting and priming, intermediate and topcoat application, and must also remain in this condition during curing of the coatings.

• As a guide, relative humidity levels of 25-80% give optimum painting conditions, although some applications may be carried out up to 85% relative humidity.




STRIPE COATING

• Primer and finish painting can be carried out on steel temperature up to 45 C.

Interchar 963 may be applied at steel temperatures between+5ºC and 30+ºC.

• Painting should not be carried out during windy conditions. • The area where Interchar 963 need to be applied must be protected from

condensation and water during application and drying.

General Site Requirements

Prior to any work being carried out there are a number of conditions which must be met.

a) Cleanliness

Any contaminants which may come in contact with the steel (even before surface preparation comments) can compromise the performance protective coating system, and as such all effort must be made to keep the working area clean. It is good working practice to establish a clean area where painting is being done. Cleanliness must be maintained throughout all stages of the application.

b) Weather Shelters

Weather shelters should be made available to cover application equipment during mixing and application of material.

c) Paint Storage Facility All paints should be stored ideally between 10ºC (50ºF) and 30ºC (86ºF) and facilities may be needed to store the materials in the correct temperature range prior to mixing and application.

d) Disposal of empty cans. All surplus materials and empty containers should be disposed of in accordance with

appropriate regional regulations/legislation.

• Stripe coating is an essential part of good working practice, and stripe coats are highlighted in the detailed product specification sheets.

• Stripe coats are applied to areas where it is difficult to get the required coverage, including but not limited to:-

Plate edges

Welds

Difficult access areas

Stripe coats are normally applied to a specified film thickness range via a combination of

narrow angle airless spray and brush methods. Over coating intervals for the stripe coats

should be strictly adhered to as per the individual product data sheet.




PAINT SPEC PRIMER COAT

INTERMEDIATE COAT

Intergard 251 • Application : By Airless Spray.

• Mixing Ratio: 4:1 by volume (Base : Hardener)

Mix the base using a power agitator Add C/A slowly during mixing and mix well for 5

minutes. Ensure complete mixing of Base and C/A.

• Tip size : 0.38 – 0.53mm (15-21 thou).

• Output fluid Pressure at spray tip : Not less than 155 kg/cm2 (2,200 p.s.i.)

• Thinner GTA220 (Use only when required).

• Check WFT during application using comb gauge. For 50 µ dft the WFT shall be 79 µ

• Ref. Chart 1 for drying time, Check DFT and record.

(For complete details of the product please refer the product data sheet)

Interchar 963

• Application : By Airless Spray, 1:68 airless machine would be ideal. For air driven

airless spray pumps the following modifications to the normal set up are

recommended.

• All filters should be removed from the pump,lines and gun.A coarse filter(1/2-1mm)can

be fitted over the wet end to prevent contamination from external sources from

entering the spray machine and causing blockages.

• Use the minimum length of 9mm bore fluid line.A 2 metre 6.5mm bore whip end with a

swivel connection to the spray gun makes the fluid lines much easier to handle and

more manoeuvrable.

• Mixing Ratio: Not applicable.(Single Component)

Mix the using a power agitator for 5 minutes. Ensure complete mixing.

• Tip size : 048 – 0.59 mm (19-23 thou)


• Check WFT during application using comb gauge

• For 100 microns dft the WFT shall be 133 microns

(For correct film thickness for various areas,refer Hp/A calculation chart provided.

• Ref. Chart 3 for drying time, Check DFT and record





• Thinning:Thinning of Interchar 963 is not normally required.

• Dry film thickness up to 750 Microns:Apply one coat of Interchar 963 as

required,up to a maximum wet film thickness of 1000 microns which will dry back to

750 microns.

If thicker coats are applied,drying and the handling time will be impaired.

Alternatively,if

the coating is built up in thinner coats,the overall drying time will be

reduced.Overcoating times for Interchar 963 with itself is coated on the technical data

sheet for the typical dry film thickness of 750 Microns.Shorter intervals may be

possible for thinner coats.

• Dry film thickness greater than750 Microns:Where the required dry film thickness

is greater than 750 Microns the coatings should be built up in two or more applications

up to a maximum wet film thickness of 1000 Microns per coat.Drying times will be

optimised if successive coats are of similar thickness.

• Overspray:Where dry overspray falls on primed surfaces before they have been

coated it will affect the adhesion of Interchar 963 and should be dusted off before

proceeding.Where it falls on areas previously coated with Interchar 963,it may give a

rough appearance to the surface.Sometimes this can be dusted off but abrasion may

be required to satisfy the specification for cosmetic appearance.

Overspray can be minimised by work planning and good spray technique.Steel work

should be arranged to allow good access for spraying al surfaces.The sprayer should

be close enough to the work surface at all times to minimise airborne overspray

without leading to excessive ripples or other texture in the coating caused by the

pressure of the spray.

• Brush application:Application of Interchar 963 by brush is an accepted method but is

generally recommended for small areas,repairs etc.

Between 250-400 Microns wet film thickness can be achieved per coat.For typical dry

film thickness required for 1 hour fire protection multi coats will be required.

The appearance of brush applied Interchar 963 will be different to that of the spray

applied coating.

• Work Stoppages. Thoroughly flush all equipment with International GTA007 cleaner.All unused material

should be stored in tightly closedcontainers.Partially filled containers may show

surface skinning and/or a viscosity increase of the material after storage.




FINISH COAT

• Clean up: Clean all equipment immediately after use with International GTA007 cleaner.It is

good working practice to periodically flush out spray equipment during the course of

the working day.Frequency of cleaning will depend up on amount

sprayed,temperature and elapsed time,including any delays.

Interthane 990

• Application : By Airless Spray

• Mixing Ratio: 6 : 1 by volume (Base : Hardner)

Mix the base using a power agitator Add C/A slowly during mixing and mix well for 5

minutes. Ensure complete mixing of Base and C/A. If 20 litres complete mixing is not

possible then proper measuring jars should be employed to ensure accuracy.

• Tip size : 0.33 – 0.45 mm (13-18 thou)


• Thinner GTA733 (Use only when required)

• Check WFT during application using comb gauge

• For 50 µ dft the WFT shall be 88 µ

• Ref. Chart 2 for drying time, Check DFT and record


INSPECTION

Film thickness control and measurement:

• The dry film thickness of Interchar 963 to be applied to individual steel sections will

vary depending on the section size and its intended configuration as well as the

number of sides to be coated,and for beams,the type of decking being supported.To

ensure efficient working the applicator should be in possession of a full list of the

specified dry film thickness and number of sides to be coated,etc and should mark the

sections accordingly.

Any method of marking must not interfere with the application or adhesion of the

coatings.

Wet Film Thickness:

• During the application of Interchar 963 frequent checks should be made on the




coating using a wet film comb to ensure that the specified thickness is achieved.Wet

film thickness readings are a guide to the applicator to enable application technique to

be monitored.They should be taken as frequently as necessary to enable a “feel” for

the coating,and the number of spray gun passes required,to be established.

On second and subsequent coats,wet film readings may be inaccurate due to the

gauge sinking in to the previous coat.

Measurement of Dry Flm Thickness:

• After sufficient drying time a survey of the dry film thickness should be carried out

using a suitable calibrated gauge.An electromagnetic induction instrument with a

statistical function to store readings and give an average is most useful.

Where dry film readings include a primer and /or top coat an allowance must be made

for these coatings and subtracted from the total reading.

The following is the recommended procedure for measuring dry film thickness.

Readings should be taken on every steel section as follows”

I Sections

Webs :One reading per metre length on each face.

Outer Flanges :One reading per metre length on each face.

Inner flanges :One reading per metre length on each face.

Hollow Sections :Four readings per metre length spread evenly around the section.

No readings should be taken within 25 mm of any edge or web/flange junction.

• Dry film thickness Acceptance criteria:

The average thickness of each section should be equal to ,or greater than,the

specified thickness.

Where any single thickness reading is found to be less than 80% of the specified

thickness,a further three readings should be taken on the same face within a 300 mm

radius of the low reading.If one or more of the additional readings are also less than

80% of the specified thickness,further readings should be taken to establish the extent

of the area of under thickness and the whole area should be brought up to the

specified thickness.

Individual thickness readings of less than 50% of the specified thickness are not




HANDLING

acceptable.

The average measured dry film thickness of any member should not exceed by more

than 10%,the maximum stated thickness for the particular steel shape and orientation

as given in the loading charts.

• Dry Film thickness of Top Coat.

The top coat dry film thickness is difficult to measure due to the variation in thickness

of the underlying coats and its own relatively low thickness.It is however,important that

the top coat is applied at the specified thickness to ensure the longevity of the system

without applying excessive thickness.Judging the thickness of the top coat is also

made more difficult as an uneven surface will require more coating to achieve a

uniform appearance.

As a guide,the number of spray gun passes to achieve the required wet film thickness

can be determined by spraying on to a smooth surface.Monitoring of material usage

will also give an indication of the applied thickness.

• Standard of cosmetic finish.

The cosmetic finish of Interchar 963 will vary depending on the method of

application.Spray application of the coating is generally considered to give a superior

appearance to brush application.

For non-visible areas,for example,the standard of finish achieved may not be of

concern.

Top coats are relatively thin and will tend to highlight rather than hide surface

defects.It is,therefore,important to ensure that the required finish has been achieved

before application of the top coat.

It is essential that steel work coated with Interchar 963 is stored and handled correctly

to minimise damage and the need for site repair.

Chains are frequently the most effective method for handling the coating when it is not

fully hard,and particularly when turning steelwork in the paintshop.The damage can be

quite deep,but localised and limited.

Straps can strip a large area of soft coating.They may make an impression on a firm

coating but should cause such severe damage as chains when the coating has

hardened.Straps may be more suitable for loading out finish coated steel work.




Once hard enough to handle,coated steel work may be removed to a laydown area

with minimal stacking and sufficient air movement to allow drying to continue.

During storage and transportation the coated steel should wherever possible be kept

in cool,shaded areas to minimise softening in high temperatures.

Erectors should use appropriate handling methods to avoid excessive damage.

After erection all transport and erection damage should be repaired in accordance

with repair procedure.

.

Repair Procedure

REPAIR PROCEDURE

Repair of Damaged areas,Erection damage etc.

The repair method will depend on the extent of the damage.Repairs should be carried out

at the earliest opportunity using the appropriate procedure from those given below.

1)Damage which exposes Bare Steel

Wherever damages exposing bare steel is observed,any of the below mentioned procedure to be followed.

Method 1

Remove any oil&grease/dust contamination etc from surface.

Spot blasting to Sa2.5 Standard

Remove unsound and damaged coatings to a neat firm edge.

Apply Intergard 251 at 50µ thickness.Follow overcoating interval.

Reinstate the Interchar 963 within the recommended over coating limits of the

repair primer.

Apply Interchar 963 in multiple applications by brush or knife,as appropriate.If

small amounts of the coating are left on a clean surface for a few minutes,solvent

flash-off will give a more “knifeable” consistency.If a top coat has already been

applied to original system,minimise overlap of fresh Interchar 963 over the top

coat.

Apply top coat as appropriate.




Method 2

Remove any oil&grease/dust contamination etc from surface.

Hand tool/Power tool cleaning to St 2 Standard as per ISO 8501.

Remove unsound and damaged coatings to a neat firm edge.

Feather coating edges by abrading.

Apply Interseal 670HS at 100µ thickness.Follow overcoating interval

Reinstate the Interchar 963 within the recommended over coating limits of the

repair primer.

Apply Interchar 963 in multiple applications by brush or knife,as appropriate.If

small amounts of the coating are left on a clean surface for a few minutes,solvent

flash-off will give a more “knifeable” consistency.If a top coat has already been

applied to original system,minimise overlap of fresh Interchar 963 over the top

coat.

Apply top coat as appropriate.

2)Damage not requiring Primer Repair.

Depending on severity of damage either lightly abrade damaged area to a

feathered edge,or cut out a suitable area of Interchar 963 and feather out the

edges.If cutting out,do not damage the priming system,otherwise repair as per above will be required.

After the appropriate overcoating Interval,apply an approved top coat in

accordance with original specification.

3)Damage to top coat only

Remove loose or unsound coatings to a firm edge and feather the edges.All

surfaces should be clean,dry and free from all contamination.Reinstate top coat

in accordance with original specification.




Chart 1: Drying Times of Intergard 251

Chart 2: Drying Times of Interthane 990

963L&T Hyderabadwp

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