Structures not of metal being scaffolding, namely, portable free-standing structures, free-standing barriers, free-standing perimeter protection barriers, free-standing pre-fabricated work platforms, free-standing stair scaffolds and free-standing stair towers; Transportable buildings not of metal being scaffolding; Non-metal scaffolding and parts thereof, namely, stair treads, guard rails, rigid tubing, rigid pipes; Walkways not of metal being scaffolding; Prefabricated platforms not of meta...