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From page 31... ... NCHRP Project 14-30 31 4.0 SPOT PAINTING OF STEEL BRIDGES Spot painting of bridges, whether performed by in-house forces or by experienced paint contractors, should have a consistent set of actions to ensure properly applied and well performing coatings. Those action steps are: 1. Read the entire page →
From page 32... ... NCHRP Project 14-30 32  Up-to-date training, testing/health screenings, and recordkeeping of workers regarding safe working practices, potential hazards and use of appropriate PPE. o Worker safety requirements are a major issue in mobilizing for painting work. Read the entire page →
From page 33... ... NCHRP Project 14-30 33 field, at least one container (typically Part A if two-component coating) should be opened and the contents checked. Read the entire page →
From page 34... ... NCHRP Project 14-30 34 Traffic control -- Necessary traffic control devices including flagging crews should be provided along with an approved traffic control plan. Once proper traffic control is in place (signs, delineators, crash barriers, and flagging) Read the entire page →
From page 35... ... NCHRP Project 14-30 35 Access equipment -- The initial work will consist of installing access equipment, including ladders, pick boards, scaffolds, mobile lift devices (e.g., bucket trucks, boom lifts, scissors lifts and under bridge platforms -- Figure 11) Read the entire page →
From page 36... ... NCHRP Project 14-30 36 Work areas – When spot painting involves existing lead paint, it may be necessary to rope off the work area and prevent public access. Once access and containment have been installed, hoses and power chords can be placed between the generators, compressors, spray pumps and pressure washers prior to the onset of work. Read the entire page →
From page 37... ... NCHRP Project 14-30 37 Coating conditions for application inspection occurs just prior to coating application. It ensures that a surface has not been re-contaminated and that the prevailing ambient conditions and surface temperature are acceptable before the coating is mixed. Read the entire page →
From page 38... ... NCHRP Project 14-30 38 Hydrophobic Surface Films by the Water Break Method." Alternatively, ultraviolet (black) light can be used to detect residual hydrocarbon films. Read the entire page →
From page 39... ... NCHRP Project 14-30 39 Even if SSPC SP 3 cleaning is specified, when encountering failed areas only possessing exposed paint, it is best to use this process if the exposed paint is adherent. The boundary around the failed coating area should be feathered by hand sanding. Read the entire page →
From page 40... ... NCHRP Project 14-30 40 Typical soluble salt contamination data may be available from coating assessments and may indicate whether a need exists to perform any type of remediation. The International Standards Organization guidance for maintenance painting recommends checking soluble salt contamination for the first 5 spots repaired and every fifth spot thereafter. Read the entire page →
From page 41... ... NCHRP Project 14-30 41 After the soluble salt treatment, the agency may elect to perform soluble salt testing to determine whether the treated surfaces are below the contamination threshold. Testing will use either the sleeve or patch method described above. Read the entire page →
From page 42... ... NCHRP Project 14-30 42 SSPC-SP 3, "Power Tool Cleaning," is intended to remove all loose scale, rust, paint and detrimental foreign matter. It is not intended to remove adherent mill scale, rust and paint. Read the entire page →
From page 43... ... NCHRP Project 14-30 43 SP 11 surface preparation initially uses grinding tools for surface cleaning followed by impact tools to create profiles though they may also remove mill scale or be used for irregular surfaces that can't be completely accessed by grinding tools (e.g. needle gun cleaning of fasteners) Read the entire page →
From page 44... ... NCHRP Project 14-30 44 Impact or rotary impact tools generate the lowest levels of airborne contaminants, which is important when leaded coatings are involved. Many of those tools have custom cleaning media/bits or come in a variety of sizes that can accommodate various surface preparation requirements. Read the entire page →
From page 45... ... NCHRP Project 14-30 45 it is a brush head assembly that allows some latitude in conforming the shroud to the work piece and thereby preventing leakage of airborne debris. The efficiency of dust collection depends upon the proper placement of the tool/shroud on the surface being cleaned. Read the entire page →
From page 46... ... NCHRP Project 14-30 46 As SP 3 cleaning is only intended to remove loose material, compared to cutting a profile in the steel substrate, the production rate is higher for SP 3 -- about 100 ft2/hour (9.29 m2/hour) compared to about 50 ft2/hour (4.64 m2/hour) Read the entire page →
From page 47... ... NCHRP Project 14-30 47 The visual standards are intended to be used in conjunction with the written standards. Sometimes existing coating conditions and/or power tools vary significantly from VIS 3. Read the entire page →
From page 48... ... NCHRP Project 14-30 48 lower limits may be recommended (e.g., 70%) Read the entire page →
From page 49... ... NCHRP Project 14-30 49 through a rust patina created by SSPC SP 3 cleaning) Read the entire page →
From page 50... ... NCHRP Project 14-30 50 kits. Dry components may be provided with a coating. Read the entire page →
From page 51... ... NCHRP Project 14-30 51 When no PDS is available or a PDS does not provide detailed application information, those guidelines are generally safe to follow. If questions remain about application issues, the manufacturer's representative can usually provide the information. Read the entire page →
From page 52... ... NCHRP Project 14-30 52 Daubers can be used for painting areas with poor access for other application methods. Paint mitts can be used to apply coatings on laced and riveted beams (Figure 30) Read the entire page →
From page 53... ... NCHRP Project 14-30 53 Wet and Dry Film Thickness Measurements An important factor in coating quality is obtaining proper cured film thickness -- dry film thickness (DFT) Read the entire page →
From page 54... ... NCHRP Project 14-30 54 temperature of the bridge steel, and for some coatings relative humidity. Some coatings have a recoat window consisting of minimum and maximum recoat times. Read the entire page →
From page 55... ... NCHRP Project 14-30 55 SSPC-PA 1, "Shop, Field, and Maintenance Coating of Metals," recommends brushing for applying stripe coats as it works the paint into the pores and crevices and allows the greatest control over the boundaries of the striped areas. Rolling can be used where striping involves coating simple shapes such as edges of girder flanges. Read the entire page →
From page 56... ... NCHRP Project 14-30 56 Inspection of Work and Affecting Repairs Once the spot coating has been applied, a final inspection can be performed of all repair areas to ensure that the work has been properly performed. For spot painting work, this includes: • Confirming that the damaged areas were completely repaired (and for the bridge that all repair locations were spot painted) Read the entire page →
From page 57... ... NCHRP Project 14-30 57 repaired like the spot painting work. The coating/coating system should also have sufficient build (thickness) Read the entire page →
From page 58... ... NCHRP Project 14-30 58 measurements on steel beams. Even for relatively small areas of a few square feet, it recommended that the reading be taken on spot repairs in both the flanges and webs if necessary. Read the entire page →

From page 31...

... NCHRP Project 14-30 31 4.0 SPOT PAINTING OF STEEL BRIDGES Spot painting of bridges, whether performed by in-house forces or by experienced paint contractors, should have a consistent set of actions to ensure properly applied and well performing coatings. Those action steps are: 1.