Wheel means a complete wheel consisting of a rim and a wheel disc;
Stack means any point in a source designed to emit solids, liquids, or gases into the air, including a pipe or duct but not including flares.
Fifth wheel trailer means a vehicle that is of such size and weight as to be movable without a special highway permit, that is constructed with a raised forward section that allows a bi-level floor plan, and that is designed to be towed by a vehicle equipped with a fifth-wheel hitch ordinarily installed in the bed of a truck.
Connector means a flanged, screwed, welded, or other joined fitting used to connect two pipelines or a pipeline and a piece of process equipment.
Fiber means a glass strand or strands which is/are protected by a color coded buffer tube and which is/are used to transmit a communication signal along the glass strand in the form of pulses of light.