35 Ill. Adm. Code 211.1130
Closed Purge System
Section 211
Section 211.1130 Closed
Purge System
"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.