"Closed purge 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 liquid or vapor from a piece or pieces of equipment to a control device, or return the liquid or vapor to the process line.
Ill. Admin. Code tit. 35, § 211.1130
Added at 17 Ill. Reg. 16504, effective September 27, 1993