(2)Definitions. - For the purpose of this rule oven or drier means any enclosed structure, receptacle, compartment or box which is used for baking, drying or otherwise processing of any article or substance at a temperature higher than the ambient temperature of the air in the room or space in which a flammable or explosive mixture of air and a flammable substance is likely to be evolved within the enclosed structure receptacle, compartment or box or part thereof on account of the article or substance which is baked, dried or otherwise processed within it.
