687Shop Painting Metal Structures

687.1-DESCRIPTION: The shop painting (coating) of metal structures shall follow the provided requirements set forth in this specification unless otherwise noted in the Contract. This specification shall apply to surface preparation, coating application, contractor/fabricator responsibilities, environmental and worker protection, and waste handling/disposal. 687.2-GENERAL: 687.2.1-Surface Preparation: Shall meet the requirements of this section. 687.2.1.2-Blasting: The compressed air used for nozzle blasting shall be free of water or oil. The cleanliness of each compressed air system shall be verified at least once per shift using the blotter test in accordance with ASTM D4285, “Standard Test Method for Indicating Oil or Water in Compressed Air”. 687.2.1.2.1-Commercial Blast: Shall meet the requirements of SSPC-SP 6 / NACE 3 prior to painting. The appearance of the steel surface after blast cleaning shall correspond to the applicable and current SP 6 pictorial standards of SSPC Vis 1. 687.2.1.2.2-Brush-Off Blast: Shall meet the requirements of SSPC -SP 7 / NACE 4 prior to painting. The appearance of the steel surface after brush off blast cleaning shall correspond to the applicable and current SP 7 pictorial standards of SSPC Vis 1. 687.2.1.2.3-Near White Metal Blast : Shall meet the requirements of SSPC -SP 10 / NACE 2 prior to painting. The appearance of the steel surface after blast cleaning shall correspond to the applicable and current SP 10 pictorial standards of SSPC Vis 1. 687.2.1.2.4-White Metal Blast: Shall meet the requirements of SSPC-SP 5 / NACE 1 prior to painting. The appearance of the steel surface after blast cleaning shall correspond to the applicable and current SP 5 pictorial standards of SSPC Vis 1. 687.2.1.2.5-Blast Media: The abrasives used for all blasting shall meet the guidelines set forth in SSPC AB1 for mineral and slag abrasives, and AB3 for ferrous metallic abrasives. Any additive mixed with the abrasive shall be approved by the Division prior to use. The abrasives used shall produce a height of profile between 1.0 and 3.0 mils. In addition, the container or bag of abrasive shall include the name of the abrasive, the name of the manufacturer, and the size of the abrasive. If any additive has been included with the abrasive, the name and the percentage of the additive shall be on the container or bag. 687.2.2-Post-Surface Preparation: Surface prep operations shall be performed in such a manner that no damage is done to p artially or entirely completed portions of the work. After surface prep, any areas that are repaired by welding shall be prepped again. Areas repaired by grinding or other means shall have the anchor pattern restored by abrasive blasting. Visible deposits of oil, grease, or other contaminants shall be removed according to SSPC -SP1"Solvent Cleaning" prior to painting. Dust, loose residues , and the removal of abrasives from pockets and corners shall be removed from prepared surfaces by 757 brushing, blowing off with clean, dry air, vacuum cleaning. The prepped surface shall be checked for cleanliness by wiping a clean, dark cloth across the surface. If residue is present, the surface shall be cleaned again and rechecked. All blast cleaned surfaces shall be painted prior to any rust bloom or flash rust occurring or within 24 hours, whichever comes first. After blast cleaning, surface imperfections that remain (e.g., sharp fins, sharp edges, weld spatter, burning slag, scabs, slivers, etc.) shall be removed. Any damage to the surface profile resulting from the removal of surface imperfections shall be re-blasted. 687.3-PAINT APPLICATION REQUIREMENTS: 687.3.1-Weather Conditions: Painting shall not be done when the ambient temperature is below 40°F or above 100°F, or the relative humidity above 90 percent (90%). The temperature of the steel must be at least 5°F above the dew point. Painting shall not be performed when the surface to be coated is sufficiently hot to cause blistering of the film or too rapid solvent release. 687.3.2-Paint Storage: Paint and thinners shall be stored in a temperature -controlled environment between 40°F and 100°F. At no time will paint be used beyond the manufacturer’s shelf life. 687.3.3-Paint Application: The blast cleaned surface shall be painted within 24 hours. In the event rust bloom or flash rusting occurs, the effected members shall be re -cleaned by blasting. The paint shall be applied by spray methods, except those areas inaccessible to spray application may be brushed. Brushes, when used, shall have sufficient body and length of bristle to spread a uniform coat. Small touch -up areas may be brushed, if approved by the Engineer. Use of an agitated pot shall be mandatory in spray application of Zinc primer. The agitator or stirring rod shall reach within one (1) inch, of the bottom of the pot and shall be in motion at all times during paint application. Coatings shall be mixe d in strict accordance with the coating manufacturer’s written instructions. Under certain conditions, it may be necessary to thin or adjust the solvent balance of the paint. The type and amount of solvent to be used shall be that listed on the coating manufacturer’s product data sheet for that material. Upon thinning, the dry film thickness requirement shall still be met. Application requirements and drying times between coats shall be in accordance with the manufacturer’s written instructions. Dry film thickness requirements shall be specified in the contract documents. Exposed steel surfaces of expansion dams shall be painted as specified for structural steel. Spray guns must be equipped with the recommended size tip for the paint product being app lied and shall be held perpendicular (90 degrees) to, and at, the proper distance from the receiving surface. Complete protection shall be provided by the fabricator against paint spatter, spillage, overspray, wind-blown paint, or similar releases. For t he fully shop painted bridge, the entire top of the top flanges for the full length of the girders will only get primer at two (2) mils dry. For weathering steel bridges, the ends of the girders, to the length specified in the plans, are painted with the whole system, and the top of the top flange at the end of girders is primed only at two (2) mils dry. The remaining lengths of the girders are left unpainted. 687.3.4-Painting Sequence: Shall be in accordance with the following: 687.3.4.1-Materials: The primer shall meet the requirements of subsection 711.6 or

711.20. The fabricator responsible for the largest percentage of the painting will choose a

758 Zinc Rich, Low VOC system. Primer coat shall have a maximum VOC of 3.5 lbs/gal. Intermediate and top coats shall have a maximum VOC of 2.8 lbs/gal. 687.3.4.2-Paint systems: 3 COAT: Primer, Intermediate, Top Coat 2 COAT: Primer, Top Coat 1 COAT: Epoxy Mastic only INORGANIC PRIME COAT: All edges, corners, crevices, bolt heads and nuts, all rivet heads, edges of flanges and plates, welds, sharp edges, in general all edges, shall receive a dusting coat, by spray application, of the same primer as the Full Prime Coat. The dusting shall ext end a minimum of one (1) inch from the edge. The full prime coat shall be applied immediately following the dusting coat. No dry film thickness is specified for this coat. Inorganic Zinc Primers are NOT to be tinted. ORGANIC PRIME COAT: All edges, corners, crevices, bolt heads and nuts, all rivet heads, edges of flanges and plates, welds, sharp edges, in general all edges, shall receive one stripe coat, by brush application, of the same primer as the Full Prime Coat. Striping shall extend a minimum of one (1) inch from the edge. The prime coat shall at a minimum, be set -to-touch before the stripe coat is applied. No dry film thickness is specified for this coat. This coat shall be tinted as allowed by the manufacturer to be in contrast to the full prime coat and intermediate coat. The tinting agent shall be the paint manufacturer’s approved tinting agent. FULL PRIME COAT: The structure shall receive one coat of a primer meeting the requirements of Section 711 of the Specifications. The primer used for the full prime coat shall be of the same type and shall be from the same manufacturer as the primer used for dusting and striping. INTERMEDIATE COAT: The structure shall receive one uniform coat of a paint meeting the requirements of If tinting is required, the tinting agent shall be the paint manufacturer’s approved tinting agent. CAULKING: Caulking shall be applied before the application of the topcoat. This includes all seams between diaphragm connections to stiffeners and splices; and seams between any connection that is riveted or bolted. Any welded connections that are not fully sealed by the weld shall be caulked with a paste type caulk. The caulk shall be pressed into the seams between the adjoining surfaces, by wetted finger or specialty tool, to insure bond and provide a smooth uniform surface. Caulking in a 3 -coat system shall be applied after the intermediate coat has cured. Caulking on a 2 -coat system shall be applied after prime coat has cured. The top coat shall not be applied until the caulking has fully cured in accordance with the manufacturer’s recommendations. The caulking material shall be compatible with the paint system being applied and shall be by written recommendation of the paint 759 manufacturer. The caulking material shall be tested for compatibility with the paint system at the same time that the paint is tested f or intercoat compatibility. Caulking operations shall be performed only when weather conditions are within the parameters as specified in section 687.3.1. TOP COAT: The structure shall receive one uniform coat of paint as designated in the plans meeting the requirements of Section 711 of the Specifications. The color shall be as designated in the plans and shall be in accordance with current Federal Standard 595. NO TOP COAT SYSTEM: Prime coated structures that will not be top coated in the fields hall meet all the requirements of section 687.3, except the dry film thickness shall be a minimum of 4 mils. In addition, the Contractor shall provide the inspection access and surface protection required in section 688.2.4.1. The repair procedures of se ction 688.3.6 shall apply. In order to keep uniformity in the color of the structure, all paint applications will require the use of the same product formulation. Erection weight and match marks shall be stenciled or painted on structural steel after the last shop coat is applied. Surfaces of steel within two (2) inches of edges to be field welded shall not be painted in the shop. 687.3.5-Inspection of Applied Paint : If in the opinion of the Engineer the coating has flaws other than deficiencies in the prescribed dry film thickness, the material shall be repaired or shall be removed and replaced. Defects in the film, including but not limited to runs, sags, mud-cracking, lifting, overspray, dry spray, pinholes, and holidays shall be corrected until a continuous uniform film has been applied. Excessive film thickness shall be reduced and insufficient film thickness shall be increased. If the thickness of the finish coat is reduced, a thin coat of the finish shall be reapplied to seal the surface and t o blend the area into the surrounding coating. Depending on the defect, total removal and replacement of the effected coating may be required. No unsightly runs or sags shall be visible. All "mud-cracking" and/or "dry overspray" in the paint film shall be removed. Excessive bubbles or pinholes shall not be visible in the coat after examination under a minimum of 8X magnification. Calibration of the thickness gage and dry film thickness measurements shall be in accordance with MP 708.40.00. 687.3.5.1-Access for Inspection: The Fabricator shall furnish suitable safe access and shall provide a time mutually agreed to for inspecting the structural steel prior to and after coating. The Division’s inspector shall approve all repairs. When provi ding suitable safe access, rubber rollers or other protective devices shall be used. Metal rollers or clamps and other types of fastenings that will mar or damage freshly coated surfaces shall not be used. No temporary attachments, supports for access, or forms, shall damage the coating system (In particular, on the fascias where bracing is used, sufficient size support pads must be provided). Any damage that occurs from such devices shall be repaired. 687.3.6-Handling Coated Steel: Extreme care shall be exercised when handling the steel in the shop, during shipping, erection, and subsequent construction of the bridge. Painted steel shall not be moved or handled until sufficient cure time has elapsed to insure no damage is done to the fresh coating. T he steel shall be insulated from the binding chains by softeners. 760 Hooks and slings used to hoist steel shall be padded. To prevent damage to the coating, diaphragms and similar pieces shall be spaced in such a way that no rubbing will occur during shipment. Upon arrival at the project site, if weather conditions were such that deicing materials from the roadway were thrown onto the steel during shipment, the contractor shall be responsible for washing the entire surface of the steel with low -pressure water to remove chloride contamination. This also includes unpainted portions of weathering steel. Water shall be from an approved source of drinking water. The water is to be applied at minimum pressure of 3000 PSI to a maximum of 4500 PSI at the nozzle end, with the nozzle held at a distance of 4” to 8” from the surface. After the low-pressure wash, a minimum of one area on each piece is to be tested for chloride contamination. The testing shall be by the CHLOR*TEST (chloride test kit) method. The maximum chloride contamination shall be 5 micrograms/cm². If the degree of contamination is above the maximum level, the steel is to be re -washed, using a mixture of low-pressure water and a solution of a commercial brand of soluble salt remover, followed by additional testing for chloride contamination. The Soluble Salt Remover shall be CHLOR*RID or equal. The steel to be washed shall not be erected until it has been washed, tested and accepted. The testing also includes unpainted portions of weathering steel. 687.3.7-Shop Repair: The requirements specified herein for provisions for inspection, mixing, thinning, temperature and humidity, and application shall govern the coating of the repaired areas. All shop repairs to the coating shall be made in strict accordance with the coating manufacturer's recommendations except where the requirements listed in this specification are more stringent. The Engineer is to review and accept a repair plan before damaged areas are repainted. The repair primer shall be fr om the same manufacturer as the original primer. Surfaces that will be inaccessible for coating after erection shall be repaired and/or recoated prior to erection. In order to avoid abrupt changes in paint thickness, the area adjacent to repair areas shall transition from zero paint thickness to full system thickness within not less than three (3) inches of the repair area by means of sanding the transition area. The requirements for the dry film thickness of the repair coats are the same as those speci fied for the paint system. Blast cleaning and application of shop primer shall not be required for mechanically galvanized or zinc rich painted bolts, nuts and washers. All welds and surfaces from which the shop coat of paint has been damaged or is otherwise defective shall be blast cleaned and painted in accordance with sections 687.2. 687.4-SUBMITTALS: Submittals shall be forwarded through the Prime Contractor and be accepted by the Engineer prior to commencement of the subject work. This is the responsibility of both the Fabricator and the Field Contractor. Electronical submittals will be accepted. 687.4.1-Quality Control Plan for Painting : Minimum requirements and document form are set forth in MP 688.02.20. 761