6 Building materials made wholly or primarily of metal, namely, pipes and couplings and fittings therefor, stairways and parts and fittings therefor, fences, hot and cold rolled sections in tube, bar, strip, flat, sheet, plate, block, rod and billet form drainpipes and parts and fittings therefor, gratings and parts and fittings therefor, manhole covers and parts and fittings therefor, manhole steps, gutters, hopper heads downpipes, handrails, access covers for underground pipework and replacement parts therefor, fabricated steel and stainless steel in strip, flat, tube, bar, square, round and hexagonal form, metal chains, shackles, bollards, metal gas tight and fire proof doors and hatches and parts and fittings therefor; common metals and their alloys, namely, steel, copper, iron, aluminum, nickel, bronze and brass in block sheet, rod, bar and tube form; scrap metal and their alloys; metal fasteners, namely, nails, tacks, staples, screws, nuts, bolts, washers, rivets, cotter pins and threaded fasteners, metal cable clips and cable trays, storage racks and racking namely, framework, cable support systems, oven rack shelving, drain pan cradles, draining basket, grilling and toasting racks, valves