Method Statement for Painting works
The purpose of this method statement is to define the blast cleaning and painting application Method of with the associated inspection and documentation requirements.
This method statement covers the minimum requirements for painting activities including surface preparation, application, materials, inspection of painting. For components such as piping, pipe fittings etc.
REFERENCES
DEFINITION & ABBREVIATIONS
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ROLES AND RESPONSIBILITIES
Quality Control Inspector (QC)
QC shall ensure through monitoring and surveillance that all painting works are executed in accordance with the project specifications and are inspected accordingly. QC shall also ensure through surveillance that storage conditions for paint material are being maintained as per manufacturers recommend actions by the respective in charge personnel. QC shall also be responsible for reporting non conformances if any and in consultation with QC engineer shall raise a NCR if required.
Blaster
Only Skilled Blaster shall be used and before commencing any painting or coating work, the skill of all blasting personnel shall be verified. For the blasters, a representative 2 m2 steel sample shall be used for the actual surface cleaning.
Painter
Only Skilled Painter shall be used and before commencing any painting or coating work, the skill of all Painting personnel shall be verified. For the painters, a suitable test area (approximately 1 m2 ) shall be painted with an agreed paint system. The test area shall be fully coated with all coating system using the tools and equipment's to be used for the actual coating work. The painted area shall be maintained for the duration of the project as a reference.
Painting Supervisor
The painting supervisor shall be responsible for ensuring preparation of surfaces to be coated correctly application of paint in accordance with the project specifications and the paint manufacturer recommendations. Furthermore the painting supervisor shall complete the painting forms as indicated in the attached forms and ensure that they are endorsed by the responsible party/QCI at the appropriate stages of process paint inspection activities.
Store Keeper
Storekeeper shall be responsible for ensuring that all paint materials are stored safely and all manufacturers recommendations are followed. Expired paint material shall not be allowed to be kept in the stores premises. A wall mounted with theromometer shall be available in the stores premises to constantly monitor & ensure that temperature and humidity conditions are acceptable as per manufacturer’s standards.
EQUIPMENTS & INSTRUMENTS
Following Equipments shall be used with valid 3rd Party calibration certificatates :
Following Instruments shall be used :
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SAFETY MEASURES
PPEs: Suitable PPEs should be worn including Blasting Hood, Cartridge Mask , Painting Gloves, Blasting Gloves, Safety Shoes, Safety Gaugles and Safety Helmet.
All works shall be carried out in accordance with MSDS manufacturer’s recommendations and project safety requirements.
Protective clothing such as goggles and aprons should be worn during solvent cleaning operations. Hands should be cleaned with a waterless hand cleaner after exposure to solvents.
Clothing or protective equipment that is wet with solvents or paint should be promptly removed and laundered before re use.
Rags and other waste material soiled with paints thinners or solvents shall be kept in tightly closed metal containers while on the jobsite and not in use. Waste materials outside plant site shall be disposed in a legal manner.
Caution should be used while selecting abrasives since some contain trace quantities of undesirable materials. A non-toxic or low toxicity abrasive should be used.
Risk Assessment or START card shall be made before starting the activity.
Material Safety Data Sheet (MSDS) or sufficient HSE data of the chemicals or materials to be used shall always be available at site for workers to follow.
MSDS safety measures or manufacturer’s safety measures shall always be followed during execution of the activity.
Suitable Fire Extinguisher shall be provided in all equipment's wherever required.
Care shall be taken to protect adjacent equipment, piping, structures, instruments, nameplates, etc. from spillage and spatter during field painting by use of adequate temporary covers. If surfaces are accidentally spattered or sprayed, the paint shall be immediately and thorougly removed for stainless steel surfaces.
The solvent used shall not contain chloride
MATERIAL SELECTION AND PAINT SYSTEM
Material Selection and Paint System shall be as per Specification which as below:
Example : Painting System Summary
Only paint and painting materials approved by company shall be used.
These materials shall be delivered to the job site in sealed and labeled containers.
The label of each can of paint shall include batch number, expiry date, shelf life and color code.
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MATERIAL STORAGE
The paint containers shall be stored in a Air Conditioned Storage that is protected from the elements well ventilated and free from excessive heat, open flame or other sources of ignition.
The date of manufacture shall be clearly marked on each paint container and paints that have exceeded their shelf life shall be discarded. The same shall be monitored on a regular basis in conjunction with the paint manufacturer instructions.
Paints and thinners shall be stored in areas that are well ventilated and as specified by the paint manufacturer.
Coating materials shall be used on first out basis and no coating materials shall be used after expiry of shelf life.
Paints that show signs of leakage or have gelled shall be discarded and any skins that have formed shall be cut and removed prior to application.
Discarded paint, empty paint buckets, thinners or any rags, cloths etc. shall be discarded into containers and hauled off to an approved dumping site.
Each batch of paint or thinner used shall be accompanied by a material certificate from the respective manufacturer. Any paint or thinner arriving on site without material certificate shall not be used until such time certification has been obtained.
MSDS shall be available in storage facility.
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SURFACE PREPARATION
Before any surface preparation is commenced, the surface shall be completely dry and free from burrs, weld spatter, flux, loose scale, dirt, oil, grease and any other foreign matter.
The preferred method of pre-cleaning is with steam (however, should be avoided in the open field). If steam cleaning is not possible, solvent cleaning shall be executed using a suitable solvent in accordance with SSPC-SP1. If so required detergent may be used to remove oil or grease.
After steam cleaning in combination with detergents or solvents the surface shall be flushed/rinsed with fresh water.
Surface preparation shall be in accordance with the minimum preparation grade to ISO 8501-1, NACE or SSPC for each paint system specified in this specification and/or the paint manufacturers recommendation.
Refer to below table for comparison of ISO grades, SSPC grades and NACE grades as below:
After the specified standard has been achieved, all dust, debris and abrasive residues shall be removed from the blasted, hand or power tool cleaned surface and the surface shall be painted before contamination or flash rusting occur.
Blast cleaning shall be executed using one (1) of the following abrasives:
Sand or other potentially silicon-containing materials shall only be used on limited scale, because of safety regulations. Compressed air for blast cleaning shall be free from water and oil.
Blast-cleaned surfaces shall provide a good anchor pattern for primers, but shall not show excessive roughness.
There is any possibility that the surface is wetted before the first coat is applied.
When the available light is less than 550 lux.
Stainless steel, hot-dip galvanized steel and nonferrous metals shall be sweep blasted (light blast cleaning) with a suitable abrasive.
For stainless steel and nonferrous metals, steel wire brushes are not allowed. Nonmetallic wire brushes and/or scrapers shall be used.
Blast cleaning at the jobsite is only allowed after approval of Client.
Note that when hand/power tool cleaning is specified, both methods are acceptable as long as the required specification will be reached, as per the specification.
POWER TOOL CLEANING (SSPC SP3)
Power tool cleaning involves the removal of loose mill scale, rust, foreign material or paint from a surface by use of power operated wire brushes impact tools grinders or sanders or a combination of these tools SSPC SP3 (St 3) and the equivalent Swedish standard s provide a visual reference for comparison.
Prior to power tool cleaning oil grease and salts shall be removed by solvent cleaning care shall be exercised in the use or power tools to prevent excessive roughening of the surface and the formation of ridges and burrs.
Excessive power wire brushing of mill scale produces a burnished slick surface not suitable for coating.
Only power sanders shall be used when power cleaning of zinc rich primed surfaces is required prior to application of top coats. Wire brushing produces a burnished surface detrimental to top coating.
HAND TOOL CLEANING
PAINT MIXING
- Paint shall be mixed thoroughly immediately prior to application mixing ratio set by the paint manufacturer shall be adhered to, recommended mixers are mechanical stirrers paddle mixers and can vibrators or shakers. If mechanical aids are not available mixing by hand is acceptable provided the following procedure is employed.
- For single packaged ready mixed materials remove a portion of liquid from the top of the container and transfer to a clean container. Mix the remaining portion with a clean broad strong paddle .use a lifting whirling motion to thoroughly incorporate the heavier liquid that has settled to the bottom replace the removed portion a little at a time mixing thoroughly each time a portion is added until the entire contents are of a uniform consistency a boxing procedure (pouring back and forth several times to clean containers) will assist in thorough mixing.
- For multi –component materials multi –component material shall be mixed in the volumes provided by the coating manufacturer.Kits shall not be broken or split without the written approval of contractor. Each component if pigmented, shall be mixed individually before combining them in the exact proportions specified. When metallic powder is one of the components, add the powder slowly to the liquid base. While mixing, continue mixing until the material is smooth and free of lumps for spray application strain mixed materials through fabric or wire mesh.
- If the paint cannot be mixed uniformly (thick sediments at the bottom etc.), it shall not be used.
- Metallic zinc or other dense pigment filled coatings shall be mechanically mixed thoroughly prior to and during paint application in field application. Applicators must constantly agitate the paint to obtain homogeneous mix.
- The pot life of any paint that is indicated in the data sheets shall be carefully noted and any mixed paint that has exceeded pot life must be discarded irrespective of its apparent condition.
- Paint shall be thinned in accordance with the manufacturer’s instructions or as called for in the project specification only thinners of a type recommended by the paint manufacturer shall be used. Thinners shall only be added under supervision and shall be thoroughly mixed into the paint. The amount of thinner used shall be measured not estimated and the percentage thinner used shall be calculated and recorded.
- Improper thinning can result in poor paint or application which will cause inadequate paint performance also improper use of thinners can result in increased emissions of volatile organic compounds (VOCS) .
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WEATHER CONDITIONS
- The painting supervisor shall monitor the weather conditions and take measurements for wet bulb temperature, surface temperature, dew point temperature, these including weather conditions (windy, wet, dry, and cloudy) shall be recorded on the daily inspection record by the painting supervisor .At the start, during and at end of work all measuring devices shall be calibrated and shall bear valid calibration stickers.
- Any significant changes to weather conditions which may adversely affect the quality of the paint shall warrant additional readings as per above
- Blasting operations shall not commence if the surface temperature is not at least 3°C above dew point temperature and if relative humidity is above 50% -85% . Priming / Painting shall only be performed when the weather conditions are within the requirements of project specification. An Elcometer disc type calculator or equivalent means should be used to determine the relative humidity and dew point.
- QCI shall perform surveillance inspection to ensure the data is collected and recorded and to ensure blasting and painting operations are performed strictly in compliance with the requirements of the project specifications.
PRE-COAT CHECKS
All visible oil grease and soil shall be removed with an approved materials the cleaned area shall than be washed in clean chloride free potable water and allowed to dry.
PAINTING
- The representative of the paint manufacturer should visit the site at regular intervals to provide technical support and shall submit a periodic report to sub-contractor /contractor confirming that painting is being carried out in accordance with the requirements and quality of work is acceptable. An adhesion test may be carried out if necessary.
- The specific paint systems that shall be used are identified in the project specifications. Application of all coating systems shall be in accordance with the manufacturer’s instructions MSDS data sheets and project requirements.
PRIMER COAT APPLICATION
- Primer coat application shall be as per project specification and product manufacturer’s recommendation / data sheets.
- Prior to application of primer all difficult to coat areas such as corners edges and welds shall be stripe coated with the specified primer.
- When inorganic zinc primer is used, checks for surface zinc oxide formation shall be made immediately prior to applying an epoxy topcoat. Any oxide formation shall be removed either by high pressure cleaning with potable water or hosing with potable water and then scrubbing with a soft brush to remove all the zinc salts. The surface shall be thoroughly dried before applying the top coat.
- Dry film thickness readings will be taken and calculated as per project specification and shall be recorded on the inspection record this applies to each individual coat to control the final thickness of the coats the QC inspector may use WFT (wet film thickness ) measurements as an indicator for final thickness.
- All the pipes and fittings will be primer coated as per the specified primer according to specifications.
INTERMEDIATE AND TOP COAT
- The paint coats shall be applied as per project specifications and product manufacturer’s recommendations /data sheets.
- No mixing of different manufacturers coating in any system is permitted. Only approved paint manufacturer products shall be applied.
- Paint shall be applied by one or a combination of the following methods.
-
- Brushing
- Roller coating
- Airless Spraying
- The method of application of coating shall also be governed by project specifications.
- Before application of intermediate coat the required primer paint touch up will be applied if any paint damage.
- Each coat shall be checked for correct average DFT by the QC or prior to application of subsequent coat.
- Surfaces shall not be re coated until the preceding coat has properly dried or cured. The surface may be considered ready for re-coating when the next coat can be applied without the development of paint film irregularities such as lifting or loss of adhesion of the undercoat. However the minimum or maximum drying or curing time specified by the paint manufacturer shall be the acceptable.
Re-coat period paint shall not be force dried so as to cause checking, wrinkling, blistering, pores formation or any condition detrimental to its appearance. Newly painted surface shall be protected to the fullest extent feasible from rain condensation, contamination snow and freezing until the coating has dried. - Preferably successive coats of paint should be of different colors however if they are of the same color alternate coats shall be tinted to produce sufficient contrast to ensure complete coverage of the surface .The final finish coat shall not be tinted. Tinting material shall be compatible with the paint and shall not be detrimental to its service life.
- Where the specified dry film thickness is not achieved additional coats shall be applied until the required thickness is obtained application shall be such that the film thickness will not affect the appearance or service life of the paint.
- All paint shall be applied either by air spray or airless spray as specified by paint manufacturer’s. The use or brushes is only allowed in the case of repairs or in difficult areas where spray technique is not practical.
- All paint shall be applied a workman like manner. The finished application shall be uniform in color texture and appearance .The work shall be free of sags wrinkles and excessive brush or roller marks any deficiencies shall be corrected by sub-contractor at own expense.
- After the completion of painting in the shop all spools/ straight run pipes shall be cleaned to ensure that spent abrasives are not present inside the pipe. Both ends shall be covered to avoid ingress of sand after cleaning.
- All welds edges etc. shall be stripe coated to ensure full DFT in those areas. This includes nuts and bolt heads.
REPAIR OF DAMAGED COATING
All the damages /defects shall be categorized as major or minor.
Major damages/defects:
The damaged area shall be completely removed by abrasive blasting as originally specified for that item and the full coating system re-applied in accordance with the manufacturer’s recommendations/data sheet.
Minor damages/defects :
Any repair of damaged coating shall be spot blasted or power tools cleaned to the original degree of cleanliness or roughness.
All repair areas shall be feathered into the undamaged coating a minimum of 50 mm. repair shall be performed prior to the subsequent coat.
Repair of damaged area shall be performed prior to the coat application coating of weld joints shall be in accordance with original paint application as specified in project specification.
For item such as equipment already painted by contractors supplier sub-contractor shall use the same paint or an equipment and compatible paint approved by contractor items supplied with the manufacturers standard coating system shall be touched –up with the same generic coating material or repainted.
Repair of damaged surfaces of zinc silicate primer shall be performed as detailed in the manufactures data sheet.
Any holidays defects and unacceptable work shall be repaired in accordance with manufacturer’s recommendations.
Holidays should be generally ground to bare metal feathering the adjacent sound coating back a minimum of 25 mm.
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TESTING AND MEASURING EQUIPMENT
The inspection measuring tools and equipment shall be calibrated and stickers shall clearly indicate therein the date of expiry certificates shall also be available and produced upon demand.
The inspection and test status shall be defined and controlled by the applicable inspection and test plan (ITP) and the respective inspection test record (ITR) inspection activities shall be recorded progressively by QC.
The QC shall perform inspection as per relevant ITP on all painting activities in addition to profile measurements and DFT checks that shall be carried out during the course of the coating application process the QC shall perform inspections on each batch and each coat and the checks shall include but not be limited to the following:
The inspection shall be witnessed and signed off by the contractor QC and company as per relevant ITP on the applicable inspection record.
When a painting manufacturer is different between shop coating and field coating adhesion testing shall be done at randomly selected areas following the procedures of ASTM D3359. Pulling off the adhesive strip should not peel off from the grid area more than what is specified /confirmed in the project specification / requirements.
Adhesion of inorganic zinc coatings shall be tested by firmly scraping the coated surfaces with the edge of a coin a zinc film, which is property dried and hard , will polish to bright metal without powdering or loss of material .
For underground piping the inspect ion on site shall be carried out using a holiday detector after the pipe is lowered in the final position and after completion of wrapping coating of joints and in accordance with ITP and project specifications . Results shall be recorded in the applicable inspection record.
Lining on internal surface of tanks and piping spools shall be finally checked for holidays and pin holes after completion of all internal work activities and man entry operations.
IDENTIFICATION MARKING – JOB STENCIL
All spools and straight run pipe shall be identified clearly as per project requirements specified in the applicable project document SPECIFICATION.
A job stencil shall be applied in the field in letters in a color which is in accordance with project specification .this shall only be applied on the final coat and shall contain the required information.
Identification markings (e.g. heat numbers, spool number, weld details, etc, ) shall be protected and transferred to the inside of the spool or tagged securely to spool ,etc. prior to blasting .
All spool and straight pipes shall be identified clearly as per procedure. Special attention shall be paid to ensure the heat number is transferred /secured properly and stays available for verification at all stages at all stages of work execution and later as required.
STORAGE AND TRANSPORTATION
All painted pipes/spools shall be properly stored clear from the ground. Pipe ends shall be protected at both ends with end caps or plastic sheet wherever end caps are not provided.
Method of storage shall protect coated pipes / spools from standing water, direct soil contact and sharp or hard objects.
Coated/painted pipes and spools shall be transferred by lifting with shovel / Forklift With Clamps attachment and placement without the use of hooks, ropes, or others sharp handling devices.
ATTACHMENTS
- JOB SAFETY ANALYSIS / RISK ASSESSMENT
- (JSA / RA)
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