Common metals, unwrought or semi-wrought; valves of metal, other than parts of machines; junctions of metal for pipes; pipes of metal; buildings, transportable, of metal; Ironmongery, namely, metal pipe fittings, metal expansion joints for piping and ducting, metal casings used to stabilize the wellbore in oil and gas wells; flanges of metal; metal pipe collars; foundry moulds of metal; containers being bottles of metal for compressed gas or liquid air, sold empty