35 Ill. Adm. Code 215.451
Sealing Device Requirements
Section 215
Section 215.451 Sealing
Device Requirements
Except for safety pressure
relief valves, no owner or operator of a petroleum refinery shall install or
operate a valve at the end of a pipe or line containing volatile organic
materials unless the pipe or line is sealed with a second valve, blind flange, plug,
cap or other sealing device. The sealing device may be removed only when a
sample is being taken or during maintenance operations.