Whenever exterior scaffolding, exterior hoists or similar equipment extends more than one hundred (100) feet above grade level, or is used at a level more than one hundred (100) feet above grade level, the Commissioner may require the use of noncombustible material or lumber treated to make it fire resistive, except that those requirements shall not apply to thrustout or catch platforms or other similar temporary assemblies of a minor nature, and provided further, that scaffolding planks, hoist platforms and swinging scaffolds may be of wood.