UL-1340:2012 pdf free download – STANDARD FOR SAFETY Hoists.
9.3.2.4 An enclosure of sheet steel 0.126 inch (3.20 mm) thick if zinc coated, or 0.123 inch (3.12 mm) thick if uncoated or heavier shall be protected against corrosion by one of the following means:
a) Hot dipped, mill-galvanized sheet steel conforming with the coating Designation G60 or A60 in Table I of the Standard Specification for Steel Sheet, Zinc Coated (Galvanized) or Zinc-Iron Alloy-Coated (Galvannealed) by the Hot-Dip Process, ASTM A653/A653M-94, with not less than 40 percent of the zinc on any side, based on the minimum single-spot-test requirement in this ASTM specification. The weight of zinc coating may be determined by any method deemed acceptable; however, in case of question, the weight of coating shall be established in accordance with the Standard Test Method for Weight (Mass) of Coating on Iron and Steel Articles with Zinc or Zinc-Alloy Coatings, ASTM A90/A9OM-93.
b) A zinc coating, other than that provided on hot-dipped, mill-galvanized sheet steel, uniformly applied to an average thickness of not less than 0.00041 inch (0.010 mm) on each surface with a minimum thickness of 0.00034 inch (0.009 mm). The thickness of the coating shall be
established by the Metallic-Coating-Thickness Test, Section 25.
c) Two coats of an organic finish of the epoxy or alkyd resin or other outdoor paint on each surface. See 9.3.2.2.
d) Any one of the means specified in 9.3.2.3.
Exception: Other metallic or nonmetallic coatings that have been determined to provide equivalent protection as described in 9.3.2.6 may be used.
9.3.2.5 The requirements in 9.3.2.4 also apply to sheet steel that is 0.056 inch (1 .42 mm) thick if zinc-coated or 0.053 inch (1 .35 mm) if uncoated or heavier for use as an enclosure that is intended to be mounted within an enclosure of other equipment (such as an air conditioner) so that it will be protected from direct exposure to weather. Such an enclosure shall not be marked rainproof or raintight.
9.3.2.6 With reference to 9.3.2.3 — 9.3.2.5, other finishes, including paints, metallic finishes, and combinations of the two may be used if comparative tests with galvanized sheet steel (without annealing, wiping, or other surface treatment) conforming with 9.3.2.3(a) or 9.3.2.4(a), as applicable, indicate that they provide equivalent protection. Among the factors that are to be considered when evaluating the acceptability of such coating systems are exposure to salt spray, moist carbon dioxide-sulfur dioxide-air mixtures, moist hydrogen sulfide-air mixtures, ultraviolet light, and water.
9.3.2.7 Test specimens of a finish as described in 9.3.2.1, 9.3.2.3(c), 9.3.2.4(c) or 9.3.2.6 (if the paint is tested) are to be consistent with the finish that is to be used in production with respect to the base metal, cleaning or pretreatment method, application method, number of coats, curing method, thickness, or the like.
9.3.2.8 A hot-dipped, mill-galvanized A60 (alloyed) coating or an annealed zinc coating that is bent or similarly formed after annealing, and that is not otherwise required to be painted, shall be painted in the bent or formed area if the bending or forming process has damaged the zinc coating. However, such areas on the inside surface of an enclosure that are not exposed to water during the rain test need not be painted. The zinc coating is considered to be damaged if flaking or cracking of the zinc coating at the outside radius of the bent or formed section is visible at 25 power magnification.