DMS-8104 Paint, Shop Application for Steel Bridge Members

Transcription

1 Paint, Shop Application for Steel Bridge Members Effective Date: January DESCRIPTION This Specification governs the shop application of paints and coatings for steel bridge members. This Specification does not address painting galvanized steel. 2. SHOP REQUIREMENTS 2.1. Certifications. Prior to beginning work, cleaning and painting contractors, subcontractors, and fabricators must provide proof of current certification in accordance with all applicable provisions for qualification specified in the AASHTO/NSBA Steel Bridge Collaboration S Access. Provide safe access and illumination meeting SSPC Guide 12 to all parts of the work for proper inspection. Do not place rigging, scaffolds, etc., in contact with previously painted surfaces until the coating is fully cured. Protect cured paint with an approved padding to minimize damage from supports, clamps, lifting equipment, rigging, scaffolds, etc Equipment. Use spray equipment that: has adequate capacity to ensure delivery of clean dry air meeting ASTM D 4285 at the proper pressure and volume for the type of paint being used; has spray heads that provide a smooth, uniform coat of paint; and has no dried coatings, solvents, or other foreign matter on surfaces that paint is likely to contact. Maintain all equipment, accessories, and safety devices in place and in good working order. Replace all worn, cracked, or damaged equipment. Provide paint pots or other containers with agitators that continuously operate during painting Airless Spray Equipment. Use regulator and air or fluid pressure gauges. Use fluid hoses with at least 1/4-in. internal diameter (I.D.) and a maximum length of 75 ft. The Materials & Pavements Section of the Construction Division (CST/M&P) may approve longer hoses due to higher ratio pumps, larger diameter hoses, or other appropriate methods. Overthinning is never an approved method Conventional Spray Equipment. Use independent fluid pressure and atomization pressure regulators and gauges. Use fluid and air hoses with at least 1/2-in. I.D. and a maximum length of 75 ft., or as approved. 3. MATERIAL REQUIREMENTS 3.1. Paint Systems. Paint systems for steel bridge members include the following. Provide System IV unless otherwise specified System III-B. Provide paint in accordance with DMS-8101, Structural Steel Paints Performance. Shop apply inorganic zinc (IOZ) prime coat and epoxy intermediate coat. Provide epoxy zinc prime coat for touchup of IOZ. Apply urethane appearance coat following erection and repair of all coating damage or deficiency. Construction Division 1 5 Effective Date: January 2015

2 System IV. Provide paint in accordance with DMS Shop apply IOZ prime coat. Provide epoxy zinc prime coat for touchup of IOZ. Apply acrylic latex appearance coat following erection and repair of all coating damage or deficiency Paint Inside Tub Girders and Closed Boxes. Provide a white polyamide cured epoxy Special Protection System. Provide the type of paint shown on the plans. Special Protective Systems must have completed NTPEP Structural Steel Coatings (SSC) testing regimen as a complete system, with full data available through NTPEP Paint for Faying Surfaces. Provide a prime coat documented to have the required mean slip coefficient shown on the plans, as determined in accordance with the procedure outlined in Research Council on Structural Connections (RCSC) Specification for Structural Joints Using High Strength Bolts. Perform all required testing at no expense to the Department. Do not apply intermediate or appearance coat to faying surfaces Sampling. Submit annual paint samples for each coating type and manufacturer of structural steel coatings used for Department projects. Sample paint in accordance with Tex-736-I. Submit a manufacturer s Certificate of Analysis or certification with the annual samples and for every subsequent batch of material used for Department projects. 4. CLEANING AND PREPARATION OF SURFACES 4.1. Pre-Cleaning. Remove surface imperfections such as sharp edges, sharp fins, weld spatter, BBs, and slag. Radius or chamfer all edges to at least 1/16 in. The radius and chamfer requirement does not apply to punched or drilled holes. Grind any areas where a uniform blast profile cannot be achieved during abrasive blasting. Flame-hardened beam ends are a particular concern. Remove all hydraulic fluid, oil, grease, dust, dirt, and other visible contaminants. Meet the requirements of AASHTO/NSBA Steel Bridge Collaboration S Abrasive Blasting. Meet the requirements of SSPC SP-10, and remove all steel splinters (hackles) or other steel defects raised or evident during cleaning. Reblasting or equivalent profiling as approved is required in all removal areas Tape Test. Perform the tape test as follows to determine surface cleanliness. Press a strip of filament tape onto the surface by rubbing with moderate thumb pressure 4 times, leaving approximately 2 in. of one end of the tape free from the surface. Grasp the free end and remove the tape from the surface with a sharp pull. The surface is contaminated and not adequately cleaned if visible particles cling to the tape. 5. APPLICATION REQUIREMENTS 5.1. General Paint Application Requirements Paint Condition. Thoroughly mix by mechanical methods and strain all paints. Ensure the paint is a homogeneous mixture free of lumps, skins, and agglomerates and contains all components required in the original formulation. Keep paint containers tightly covered and protected from weather when not in use Thinning. Adjust paint to the correct application consistency as allowed by the manufacturer s instructions. Measure all thinner used Cleanliness. Immediately before each coat of paint, ensure surfaces are free of hydraulic fluid, oil, grease, dust, grit, or other contaminants. Re-clean if such contaminants are present. Construction Division 2 5 Effective Date: January 2015

3 Environmental Conditions. Follow product data sheets for temperature and humidity requirements for all paints. Measure humidity in accordance with ASTM E 337. Do not apply paint to any surface with discernible moisture. Use environmental controls to meet humidity requirements, if necessary. Ensure conditions will remain within recommended levels until cure is complete Application. Follow manufacturer s instructions and the paint application guidelines of AASHTO/NSBA Steel Bridge Collaboration S8.1, unless contradicted by this Specification or the plans. During painting operations, keep paint pots no more than 20 ft. above or below the level of spray application of paint. Do not allow fluid hoses to sag more than 10 ft. below the level of the bottom of the paint pot or actual spraying operations, whichever is the lower point. Ensure continuous agitation of mixed paint in the paint pot or other container. Apply each coat of paint to clean, dry, firm surfaces complying with all specification requirements. Ensure that each coat dries to form a smooth, continuous, tightly adhering film of uniform thickness and appearance, free of sags, runs, pinholes, holidays, overspray, or other defects. Apply all coats by spray, except use any approved method of application to paint inaccessible areas. Prevent contamination of freshly applied paint. Repair all defects in each coat of paint and ensure full cure of all coatings before application of subsequent coats. If, in the opinion of the Engineer, there is an objectionable amount of dust in the atmosphere, discontinue painting or take necessary precautions to prevent dust and dirt from coming in contact with freshly painted surfaces or with surfaces before the paint is applied Workmanship. Perform all painting with skilled painters who can adjust equipment and application techniques as dictated by the type of paint, environmental conditions, and size and shape of the surface being painted. Painters who, in the opinion of the Engineer, do not adjust equipment to apply coatings in a uniform full wet coat free of runs, sags, holidays, and overspray will not be considered skilled painters and may be removed from painting operations. Apply sprayed coatings in accordance with AASHTO/NSBA Steel Bridge Collaboration S8.1 and SSPC PA-1. Brush application for touchup is acceptable as long as the paint is mixed in the appropriate proportions by weight and is agitated continuously during the painting operation System Application Requirements Systems III-B and IV Prime Coat. Apply at least 3.0 to a maximum of 10.0 mils dry film thickness (DFT) of IOZ primer to all steel surfaces including splice plates, except as otherwise specified. Extend the full primer at least 1-1/2 in. onto surfaces that will be in contact with concrete, such as top flanges, as shown in Figure 1. Coat the remaining portion of the surfaces to be in contact with concrete with a continuous film coat of tightly adhering primer (no minimum DFT). Test the IOZ primer for cure in accordance with ASTM D If the IOZ primer does not meet a rating of 4 or higher, reapply a fine mist of potable water until the coating is cured. Alternative cure tests may be used if approved. If the IOZ primer is mud-cracked or otherwise discontinuous, repair the coating in accordance with AASHTO/NSBA Steel Bridge Collaboration S8.1. Construction Division 3 5 Effective Date: January 2015

4 Figure 1 Application areas of primer Stripe Coat System III-B only. Brush apply a stripe coat of intermediate epoxy onto all edges, welds and other discontinuities. Extend at least 1 onto flat steel in all directions. Do not stripe faying surfaces Intermediate Coat System III-B only. Apply at least 2.0 mils DFT of epoxy intermediate coating after primer has met curing requirements. Extend the intermediate coat at least 1-1/2 in onto surfaces that will be in contact with concrete. Do not apply to faying surfaces Appearance Coat System III-B and IV. Field apply at least 2.0 mils DFT of appearance coating in accordance with Item 446. Do not apply to faying surfaces. Appearance coats do not have to be applied to surfaces that will be in contact with concrete Paint Inside Tub Girders and Closed Boxes. Apply at least 3.0 to a maximum of 10.0 mils DFT of paint over all inside surfaces that will be visible after final bolting including exposed surfaces of interior splice plates Special Protection System. Apply paint as shown on the plans Faying Surfaces. Shop prime faying surfaces on main members and splice plates when using IOZ primer (System III-B, System IV, and some Special Protective Systems). Faying surfaces of weathering steel members and plates do not need to be primed, if exterior exposed weathering steel will not be painted Painted. Ensure that the primer used is documented to have the required slip and creep characteristics. If no mean slip coefficient or corresponding surface condition is specified, ensure a Class A slip (minimum slip coefficient of 0.33). Construction Division 4 5 Effective Date: January 2015

5 Apply no more than the maximum average film thickness used in the qualifying test to the faying surfaces. Do not touch up or repair primer with organic zinc. Occasional low DFT on a faying surface must not be cause for rejection. Before bolting, ensure that paint on faying surfaces has cured for the minimum time used in the qualifying test, adjusted for cure temperature. Perform all required testing of the paint at no additional expense to the Department Unpainted. If faying surfaces are specified as unpainted, provide an SSPC-SP 10 blast-cleaning, and ensure that these areas remain free of paint and overspray. Remove tape from masked areas as soon as practical No-Paint Areas at Field-Welded Connections. Do not paint surfaces within 4 in. of groove welds or within 2 in. of fillet welds. Do not apply intermediate coat within 4 in. of the edge of primer at these areas. Remove tape from masked areas as soon as practical after painting. 6. REPAIRS Repair or completely remove and replace all paint that has been applied improperly, has been applied to improperly cleaned surfaces, fails to dry and harden properly, fails to adhere tightly to underlying metal or other paint film, or does not conform with this Specification. Remove freshly applied paint that has not yet set with the use of suitable solvents. Remove dried paint films with blast cleaning or power tools, as approved. If repairs must be made after the primer has cured, remove damaged or noncompliant paint and feather edges of sound paint around cleaned areas by sanding at least 1 in. onto sound coating and creating a smooth transition. Use epoxy zinc primer to repair the IOZ primer. Areas of low millage may be built up with OZ repair on an occasional basis, or for an approved fabrication process. Unapproved, frequent undermillage of IOZ is considered a process issue, which must be corrected. Repair areas require a minimum of 4.0 mils DFT of primer. Ensure marks are minimized and repair areas are well adhered. Repair all damaged coating as directed. The Department reserves the right to inspect, explore, and test improper surface preparation or any painted surface at any time. Repair these areas of investigation at no additional expense to the Department. 7. HANDLING, MARKING, AND SHIPPING Pad the blocks, chains, slings, braces, clamps, etc., used for handling, moving, storing, and shipping painted members to prevent paint damage. Paint erection marks for field identification of members upon previously painted surfaces. Do not load pieces for shipment until coatings are thoroughly cured. Except for small approved touchups, do not apply any paint after material is loaded for shipment. Construction Division 5 5 Effective Date: January 2015