Closed-vent system
Closed-vent system means a system that is not open to the atmosphere and that is composed of piping, connections, and, if necessary, flow-inducing devices that transport gas or vapor from a piece or pieces of equipment to a control device.
Source
40 CFR § 264.1031
Scoping language
As used in this subpart, all terms not defined herein shall have the meaning given them in the Act and parts 260266.