12425 Iron & steel work
Bare iron and steelwork including sheeting and pipes shall be thoroughly prepared by removing all dirt, rust and loose mill scale to approval.
Painting shall be carried on after all hardware & iron mongeries are removed. Blasted surfaces shall be brushed or cleaned by vacuum.
They shall not be touched by hand or contaminated in any other way. Surfaces shall be protected within 4 hours of having been blast cleaned. Sample blast adequately protected by sealed clean polyethylene wrapping, shall be submitted for approval before any work is put in hand. The approved sample shall then be retained by the Engineer for comparison with the prepared steel work.
Mechanical cleaning shall be carried out by power driven tools, such as carborundum grinding discs, chipping hammers and needle guns, followed by steel-wire brushing and dusting to remove all loosened material. Excessive burnishing of the metal through prolonged application of rotary wire brush shall be avoided. Surfaces shall be protected within 4 hours of having been mechanically cleaned.
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