SECTION 1070 — PAINTING EXISTING STRUCTURAL STEEL
1070.1 DESCRIPTION —
This work is the painting of existing bridges using a self-curing, inorganic, zinc-rich coating system selected from one of the systems listed in "Approved Three Coat Inorganic Zinc-Rich Systems" in Bulletin 15.
1070.2 MATERIAL —
1070.3 CONSTRUCTION —
(b) Surfaces to be Painted.
Unless otherwise specified, paint all surfaces previously painted and all surfaces of new metal. Do not paint aluminum and galvanized metal surfaces, unless otherwise directed.
Sections 1060.3(b)1., 2., 4., and as follows:
Blast clean all steel to a near-white condition, as defined in SSPC-SP10-85, using acceptable abrasives. Determine the near-white condition by use of SSPC-VIS 1-89.
Prior to proceeding with the production blast cleaning operation, prepare test sections on each structure of at least 9 square feet, in locations considered by the Inspector to be representative of existing surface conditions and structural characteristics. Blast clean test section areas using the same equipment, materials, and procedures that will be used for the production blast cleaning. Provide safe access for close visual inspection and testing. Do not proceed with the production blast cleaning operation until the Inspector agrees that the surface of each test section has been prepared to conform with specified requirements.
Blast clean to leave an anchor pattern from 1 1/2 to 3 1/2 mils deep in a dense, uniform pattern of depressions and ridges. Determine pattern depth by the Keane-Tator Surface Profile Comparator or Testex Replica Tape.
Grind laminations raised by the blasting operation to a flush surface and reblast the ground area to obtain the specified anchor pattern.
A slight residue of paint or rust in seams between plates and around rivet heads is acceptable and need not be completely removed.
Clean dry-blasted surface with clean bristle, fiber, or hair brushes; compressed air; a vacuum; or a combination thereof. Remove traces of blast residue from the surface and from pockets and corners. Equip compressors with separators or traps to remove water and oil.
If water is used in the cleaning procedure, assure that surfaces, pockets, and corners are dry and clean before applying paint. Allow a minimum of 48 hours of ambient air drying; then, remove rust bloom by dry blasting and clean to remove blast residue from surfaces, pockets, and corners. Do not use rust inhibitors.
(d) Acceptable Abrasives.
Select abrasive size and type based on the type, grade, and surface condition of the steel to be cleaned and on the finished surface condition to be attained with the paint that is to be applied.
Use abrasives for blast cleaning free of oil, grease, or other deleterious contaminants.
Use recyclable abrasives of aluminum oxide, silicon carbide, zirconium aluminum oxide, steel grit, or steel shot.
When using steel grit or shot under atmospheric conditions that cause these abrasives to rust, use dehumidification equipment to prevent rusting which will adversely affect the cleanliness of the blasted surface.
Recycle abrasives to create the least amount of waste practicable. Equip the reclamation system with dust collectors to ensure that discharge meets air quality requirements.
Use nonrecyclable abrasives only when specified, and then only low-dust abrasives such as Black Beauty (under 100 psi nozzle pressure), Star Blast, or an approved equal.
Sections 1060.3(c)1., 2., 3., 4., 6., 7., and 8.
1070.4 MEASUREMENT AND PAYMENT —
Most Current Supplement
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