The complete structure, process piping, equipment, and miscellaneous structures should be coated as designated in these specifications.
Required equipment should be provided and maintained in first class operating condition. All construction of scaffolding should be performed by skilled labor to provide safe and accessible working conditions. All surface preparation, coating application, and inspections should be performed by skilled labor to achieve a satisfactory coating system as outlined in these specifications.
Necessary precautions should be taken to prevent damage to any equipment not subject to protective coatings while in the process of conducting the work specified in these specifications. All items or materials damaged should be either repaired or replaced at no cost to Buyer.
One of the paint systems specified in Section 8 should be applied to all exposed exterior steel surfaces, except where noted, after sandblasting. If a specific option is indicated, this option should be used as specified throughout the coating operation in accordance with these specifications.
The same manufacturer's paint systems should be followed for both fabrication and field erection. No mixing of different manufacturer's products will be permitted without written permission from Buyer.
Supplier should be responsible for consulting the coating manufacturer and OSHA as to potential health and fire hazards, first aid, and fire extinguishing equipment required and procedures for cleaning up spills.
All control valves, level instruments, controllers, etc. should be coated in accordance with this specification. Special care should be taken during the coating process. Enclosed components such as pressure controllers, positioners, gauges, etc. should be masked off to prevent damage from sandblasting and paint.
4.0 Surface Preparation
The surface preparation of all steel surfaces to be coated should be cleaned to "near white" metal surface with a uniform gray white metallic color, slightly roughened to form an anchor pattern in accordance with the coating manufacturer's recommendations. The surface should be free of all mill scale, rust corrosion products, oxides, paint, oil, or other foreign matter. Sandblasting per SSPC‑SP10, latest edition, should be used whenever possible.
All fabrication and assembly should be complete before final painting begins, except as permitted by the Buyer's representative.
All welded areas and appurtenances should be given special attention for removal of welding flux in crevices. Welding splatter, slivers, laminations, and underlying mill scale not removed during fabrication and exposed before and during sandblasting operation should be removed by mechanical means per SSPC‑SP2 and SSPC‑SP3 with edges smoothed or rendered flush and the area then sandblasted to provide a continuous anchor pattern.
Prior to sandblasting, all grease, oil, and waxlike deposits should be removed by "solvent cleaning" as per SSPC‑SP1, latest edition. All chemical contamination should be neutralized and flushed completely from the surface.
Bolt holes should be drilled and deburred prior to sandblasting.
All tags, nameplates, instruments, controls, electrical fixtures, flange faces, machined surfaces, process openings, stainless steel, plated bolting, non-metallic products, rotating parts of machinery, and aids to navigation should be protected to prevent damage during sandblasting and painting. Where practical, electrical cable and pneumatic tubing should be installed after sandblasting.
Only dry sandblasting procedures should be allowed. The compressed air supply used for blasting should be free of detrimental amounts of water and oil. Adequate separators and traps should be provided. Moisture and oil should be continuously drawn off. The blast nozzle pressure should be a minimum of 100 psig at a minimum of 200 cubic feet per minute at the blast nozzle.
The blasting materials should be new, clean, and washed neutral dry silica sand or packaged flint, free of clay or other matter likely to become embedded in the steel surface and sized to give the specified anchor profile as determined by SSPC‑SP10. The maximum sand particle size should be that capable of passing through a 16‑mesh screen.
The use of centrifugal wheels to propel the abrasive, the substitution of grit or shot as an abrasive, or machine shot blasting, should be acceptable only if the Supplier can demonstrate that an anchor pattern with a minimum of 1.5 mils and a maximum of 2.5 mils is being produced. Blast materials containing impurities or inclusions should not be allowed in any case.
Blasting should be done in an area removed from painting operations and previously coated surfaces subject to damage and/or to contamination.
All blasted surfaces should have a 1.5 mils minimum anchor pattern and should not exceed a 2.5 mils maximum anchor pattern profile height with the exception of areas requiring glass flake coatings which should have a minimum anchor pattern of 3.0 mils. The anchor pattern should be uniform throughout the area covered.
It is desired that blasting be done during daylight hours. Surfaces should not be wetted after blasting or before painting. If blasting is allowed during the night, the surfaces should be swept clean and bright the next morning with fresh light blasting performed to provide the "near white" blasted surface.
The blast-cleaned surface should be rendered dust free and coated with one coat of primer as specified during the same day as blasted and prior to sundown of that day and also before any rusting occurs. A minimum of four inches around the edge of blasted areas should be left unprimed unless adjoining a coated surface. Blasting should continue a minimum of one‑inch into adjoining coated surface. Any steel not primed or wetted by rain or moisture should be reblasted if any rust develops.
No acid washes or other cleaning solutions or solvents may be used on metal surfaces after being sandblasted. This includes any inhibitive washes intended to prevent rusting.
Power tools as specified in SSPC‑SP3, "Power Tool Cleaning", may be used to obtain the "near white" metal surface operation where sandblasting is not possible or on items which might be damaged by sandblasting.
5.1 General Requirements
All coating application should be performed according to paint manufacturer's recommendations.
All coating materials should be furnished in unopened, clearly identifiable containers. No materials should be used which have been stored beyond the manufacturer's recommended shelf life.
No finish coating should be applied prior to fabrication and assembly without prior approval.
Piping and equipment which is to be insulated should be primed only, using a prime coat in accordance with the coating system specified for the unit.
Nozzles should be painted on the flange edges, inside bolt holes, and up to the gasket surface.
Epoxies should not be applied at temperatures below 500F unless prior approval is given.
Painting should be permitted during daylight hours when steel temperature is between 400F and 1000F. No painting should be permitted when steel is wet from rain or dew. Painting should not be allowed when surfaces are less than 50F above the dew point or when the relative humidity is greater than the manufacturer's recommendation.
All coatings should be allowed to dry thoroughly for the specified time prior to application of succeeding coat. Twenty-four hours should be the minimum drying time between coats unless a shorter drying time is approved.
All components should be thoroughly stirred before, during, and after mixing. The mixed coatings should be continuously stirred by mechanical spray pot agitators or other approved means. The volume to be mixed should be accurately measured. All mixing should be done in clean containers, free from traces of grease, other type paints, or other contaminants. All containers should be kept covered to prevent contamination by dust, dirt, or rain. All power driven equipment should be rated as explosion proof.
Supplier should be responsible for supplying conventional and any power mixing equipment that conforms to the requirements of this specification and the coating manufacturer.
Only sufficient volumes for the appropriate pot life or application should be mixed at one time. Manufacturer's recommended pot life should not be exceeded and when this limit is reached, the spray pot must be emptied and cleaned, material destroyed, and new material mixed.
Coating should be applied in not less than the number of coats specified and should have dry film thicknesses not less than the minimum thickness indicated. The last coat on any surface should be the indicated finish coat. Total dry film thickness before application of the finish coat should be not less than the total indicated minimum thickness or an additional intermediate coat should be applied as directed by the Buyer's representative.
The surfaces must be clean, free from dust, and dry before priming or application of any coat of paint.
No coating should be placed on edges prepared for field welds or within two inches of these edges. Painting should not be allowed closer than six inches from the unblasted areas.
After the prime coat has been applied, all hard-to‑spray areas, such as corners, edges, and welds, should be brush painted with 5 mils of the specified epoxy coatings.
Each coat is to be applied uniformly and completely over the entire surface. Skips, sags, and drips are to be avoided. Holidays in the final coat at edges, corners, welds, and inaccessible areas should be prevented by hand brushing an additional layer of topcoat.
Any and all thinning should only be performed in strict accordance with the coating manufacturer's instructions and with thinners recommended by the coating manufacturer.
Supplier should be responsible for consulting the coating manufacturer as to the necessity of a "mist coat" of epoxy coatings over inorganic zinc or zinc rich primers.
Prior to the application of any coat of material, all damage to previous coats should be touched up as follows:
- Areas where the coating is damaged as the result of improper application or mechanical damage should be repaired by power wire brushing to the prime coat (if the prime coat has not been damaged) followed by replacing that portion of the coating system removed as recommended by coating manufacturer.
- Areas where the coating system is damaged through the prime coat should be repaired by sandblasting the area to "near white" metal and replacing that portion of the coating system removed.
5.2 Conventional spray application
The compressed air supply used for conventional spray equipment should be of sufficient size to provide a continuous volume at the spray nozzle of 20 CFM air at 80 psig. The compressed air supply should be free of detrimental amounts of water and oil. Adequate separators and moisture traps should be provided in the air supply line to pressure‑pot and spray gun. Moisture and oil should be continuously drawn off.
Regulators and gauges should be provided for both air supply to pressure‑pot and air supply to spray gun. Regulators and gauges should be in good accurate working condition. Operating pressures should be in strict accordance with coating manufacturer's recommendations.
Pressure‑pots should be equipped with dual regulators, a continuous mechanical agitator, a 25‑foot maximum length 5/16 inch I.D. air hose and 25‑foot maximum length 1/2 inch I.D. material hose. Pressure‑pot should be kept at the same elevation as the spray gun operator.
Pressure‑pots, material lines, and spray guns must be clean before adding new materials. All cleaning solvents should be as specified by the coating manufacturer.
Fluid pressure should be maintained and regulated to deliver not more than 24 ounces per minute of material from spray gun. Atomizing air should be adjusted at the lowest air pressure to minimize an orange peel appearance.
The spray gun should be held no closer than six inches or more than eight inches from surface to be coated, unless a greater distance is specifically recommended by the coating manufacturer, and should normally be held at right angles to the surface.
Even parallel passes should be made with spray gun. Arching of the spray gun should not be tolerated. Where deep pitting exists in the steel surface and at weld areas, several passes of the spray gun should be employed approaching from different sides and perpendicular to all surfaces.
Each spray pass should overlap the previous spray by 50 percent. All runs and sags should be brushed out immediately or the paint should be removed and the surface re‑sprayed.
Large surfaces should always receive passes in two directions at right angles to each other (cross hatched). This procedure is sometimes referred to as multi‑pass coating.
5.3 Brush Applications
Coating should be brushed on all areas which cannot be properly spray coated for any reason. Brushes should be of style and quality that should enable proper application of materials.
Brush width should be no greater than five inches.
Paint should be worked into all crevices and corners, and all runs or sags should be brushed out in order to assure no air pockets, solvent bubbles, or voids.
All grating, ladders, cages, stairways, walkways, miscellaneous hardware, and other items so specified should be hot‑dipped galvanized in accordance with American Society for Testing and Materials, ASTM Designation A-123, "Zinc (Hot‑Galvanized) Coatings on Products Fabricated from Rolled, Pressed and Forged Steel Shapes, Plates, Bars and Strip", latest edition; except that the weight of the zinc coating per square foot of actual surface should average 3.0 ounces and no individual specimen should show less than 2.5 ounces.
Hot-dipped galvanizing of bolts, nuts, washers, and miscellaneous manufactured items should be in accordance with ASTM Designation A‑153, "Zinc Coating (Hot Dip) on Iron and Steel Hardware", latest edition; and ASTM Designation A‑143, "Safeguarding Against Embrittlement on Hot Galvanized Structural Steel Products", latest edition.
All galvanized surfaces shown to be painted should be first cleaned with detergent. Any loose oxide should be removed by brush‑off blasting in accordance with SSPC‑SP7. The first coating should be applied as soon as possible as specified in Section 8.0 of this specification.
Galvanized members which are to be permanently fixed to the structure by welding should be attached after the supporting members are primed, but before top coats are applied to the supporting members. The heat affected area should be cleaned of all welding flux, then sandblasted and primed with the same coating.
All grating support members must be finish coated before securing the grating.
All damage to galvanized items caused by fabrication, welding, handling, or loading out should be sandblasted and metallized according to the specifications set forth by the Metallizing Engineering Buyer, Inc., for their Metco System 110, or an approved equivalent.
Buyer should be represented by an inspector who should inspect all surface preparation and coating applications to ensure conformance to these specifications.
All aspects of the job should be accessible to the Buyer's representative.
The Buyer's representative should have the authority to inspect any materials, tools, or equipment used in the coating procedures and surface preparation operations.
The Buyer's representative should have the right to condemn any and all material, work, or equipment which does not comply with the specifications.
The Buyer's representative should be given at least five days notice prior to the initial starting of any work covered by this specification. No surface preparation and/or coating application should be done in the absence of the Buyer's representative without his knowledge or consent. Should he be unable to be on the job after reasonable notice has been given, the Supplier may begin work without the Buyer's representative present.
Buyer's representative and Supplier should inspect each coat with respect to specified manufacturer color, dry film thickness, and appearance. Each coat should be free of runs, sags, overspray, holidays, foreign debris, or any other signs of improper application. The Supplier should make all necessary repairs of such coating conditions before proceeding to the next coat.
Dry film thickness should be checked by Buyer's representative and Supplier using an "Elecometer", "Mikrotester", or other calibrated film thickness gauge on each and every coat of a system. Those areas found to be below minimum should be recoated at the Supplier's expense until the specified minimum dry film thicknesses have been obtained.
Prior to the final acceptance of the paint work, the Buyer's representative should conduct a final inspection. Dry film thickness readings should be conducted as follows:
- Ten measurements should be made for every one hundred square feet, or portion thereof, coated area.
- Ninety percent of all measurements should be as specified within these specifications.
- Where thicknesses fall below specified minimums as determined above, an additional finish coat should be applied.
All holiday repairs and recoating should be preformed to achieve the coating system specifications and should be for the Supplier's account. The final coat should be checked for holidays over the entire surface, including all weld areas, edge and corners. A "Tinker‑Razor" or equal holiday detector set at a resistance determined by the coatings manufacturer for the proper dry film thickness should be used.
8.0 Paint Systems
8.1 External Coatings
a) Production Equipment, Piping, Structural Steel, Equipment Skids