5-92 profile, mixing, thinning, application, and cure time for the e ntire range of allowable environmental conditions and the DFT.
506.12 Limits of Work Coat all surfaces exposed in the assembl ed product unless
otherwise specified. Apply a mist coat, 0.5 to 1.0 mils, of pr imer only to surfaces to be embedded in concrete. Apply primer to faying surfaces of bolted connections that deve lop a class B slip coefficient in accordance with the “Specification for Structural Joints Using ASTM A325 or A490 Bolts” by the Research Council of Structural Connections (RCSC). Provide documentation to demonstrate that the primer was tested and the requirements were met. Do not exceed the DFT applied for test purposes.
506.13 Surface Preparation Surface cleanliness shall be SSPC-SP 10, Near-White Blast
Cleaning (SP 10) unless a higher standard of surface cleanliness is requ ired by the manufacturer's published data sheet. Round all corners exposed in the assembled product to approximately a 3/32 inch radius, prior to abrasive blast clean ing. A series of tangents that approximate a radius may be considered as a rounded edge if the re are no sharp breaks. Provide radius gauges to inspect corner preparation. The radiu s shall be the minimum specified above, but not greater than 3/16 inch. The abrasive blast media shall meet the requirements of SSPC-AB 1, Mineral and Slag Abrasives, AB 2, Cleanliness of Recycled Ferrous Metallic Abrasives and/or AB 3, Ferrous Metallic Abrasive . The anchor profile shall be angular and meet the requirement s of the coating manufacturer's published data sheet. If compressed air is used for abrasive blast cleaning, perform a blotter test ASTM D4285 at the beginning of each shift and at any time requested by the QAI. Notify the QAI prior to performing the test. Measure and record the anchor profile in accordance with ASTM D 4417 Method C (replica tape). If the anchor profile fails to meet the minimu m requirements, re-blast the substrate until the required anchor profile is achieved. If th e anchor profile exceeds the maximum allowed, generate a Non-Conformance Report (NCR) descri bing the condition of the substrate and a proposed solution and submit it to the Fabr ication Engineer for review. Measure the anchor profile of the substrate on every plane of e ach beam or girder. If it has been established to the satisfaction of the QAI that the ab rasive blast equipment is capable of providing uniform, acceptable anchor profile, a dimi nished degree of testing may be allowed at the discretion of the Fabrication Engineer. The allowable time between abrasive blast cleaning and primer a pplication shall not exceed the manufacturer’s published recommendations or one work shift, whichever is less. Any evidence of rust bloom, flash rust or other surface conditi ons that cause the substrate cleanliness to fall outside the specified cleanliness standard will be rejected. Inspect all 5-93 substrate immediately prior to coating application. Re-blast s teel substrate that does not meet the surface cleanliness requirements.
506.14 Mixing and Application Record the batch and lot numbers of the coating, the
type and amount of thinner used, the time and pot life of the c oating. Add thinner in accordance with the manufacturer's published dat a sheet. Measure thinner with a graduated cup, or other container, that clearly indicates the amount of thinner being added. Record the amount of thinner added. Mix the pain t using the method, equipment and time recommended by the coating manufacturer. Mix each component separately and mix all components together for at least the min imum time recommended on the Manufacturer's Product Data Sheet but not less than two min utes. Measure the environmental conditions in the immediate vicinity of the piece(s) being coated during the coating operation and during the entire cure period. Provide two data loggers capable of measuring ambient humidity and temperature. The data loggers shall come with software that can download the data onto a computer. Print out the data and provide a copy to the QAI for rev iew prior to applying the subs equent coat of paint. Place the data loggers in the immediate vicinity of the coating opera tion during the entire application and curing cycle. The data will be used to determi ne that the cure/recoat time requirements for each coat have been met. Failure to comply wi ll result in the coating being cured for the maximum time necessary to assure adequate cure, a s determined by the Fabrication Engineer. Stripe all corners, fasteners, welds and locations with poor ac cess, in accordance with SSPC-PA 1, Shop, Field and Maintenance Painting of Steel (PA 1). Do not stripe using inorganic zinc primer (IOZ). Stripe the IOZ primer between the primer and intermediate coats using the intermediate coating. Apply the coating using equipment recommended in the Manufactur er's Product Data Sheet, or equal. Apply the coati ng in a uniform manner without sags, runs or drips.
506.15 Dry Film Thickness Measure and record the DFT of each c oat in accordance
with PA 2. Record the following:
A.Gauge type/manufacturer/model B. Serial number C. Coat/shim used for calibration (e.g., Primer Coat or 5 mil s him)
D.Measurements/spot average/location E. Cure time F. Non-conforming areas and determination for correction Each piece or area presented for acceptance, regardless of size , shall be considered a separate structure for purposes of determining the number of sp ot measurements to be taken, except that large quantities of small parts and/or secondary fr aming members coated at the same time may be measured at a lesser frequency, as directed by the Fabrication Engineer. 5-94 When random DFT testing of a large quantity of small parts and/ or secondary framing members results in unacceptable DFT’s, the Contractor shall hav e the option of measuring and documenting the DFT of each piece or removing the coating a nd/or recoating all pieces represented in the production lot.
506.16 Touch-up and Repairs Touch-up is the repair of minor bl emishes, including but
not limited to, scratches and abrasions that to do not penetrat e underlying layers of coating. Perform touch-up using the same coating and methods specified i n the Manufacturer's Product Data Sheet. Cure the touch-up coating in the same mann er as the original coating. Repair coating damage that penetrates underlying layers in acco rdance with the Manufacturer's Product Data Sheet and this Specification. Prep are areas to be repaired in a manner that assures the proper adhesion of each coat. Feather back each damaged layer so that each repair coat is continuous with each corresponding exi sting coat. The topcoat shall be smooth and uniform in appearance. Repair damaged or unaccep table shop coating before the piece is removed from the paint area.
506.17 Handling and Storage Handle coated members in a manner that avoids damage
to the coating. Lift and move members using non-metallic sling s, padded chains and beam clamps, softeners or by other non-injurious methods. Store pai nted material in a manner that prevents damage to the coating. Document damage to the coating t hat is discovered after the pro duct is loaded for shipment to the job site. Minor damage as a result of handling shall be considered field repair unless, in the opinion of t he Fabrication Engineer, the damage is the result of negligence or poor handling methods. Damage that is deemed to be the result of negligence or poor handling methods shall be repaired as directed by the F abrication Engineer.
506.18 through 506.19- Reserved
HOT-DIP GALVANIZING
506.20 Description This work shall consist of surface preparat ion and application of
hot-dip galvanizing in accordance with the Plans and this Speci fication. Hot-dip galvanizing shall meet the requirements of AASHTO M111/ASTM A123, Standard Specification for Zinc (Hot-Dip Galvanized) Coatings on Iron and Steel (A123), including any applicable requirements listed in Section 2-Referenced Docu ments. The minimum average coating thickness grade shall conform to Table 1. The frequency of testing shall be in accordance with Section 6. The choice of the test method is the prerogative of the Contractor. Record the test re sults and provide them to the De partment. Provide certification of compliance and written test results to The Dep artment in accordance with A123 -Section 10.
Source: Maine Standard Specifications for Road and Bridge Construction, 2020 Edition. Pages 384–386 of 817.