Section 721.954  Standards:  Pressure Relief Devices in Gas/Vapor Service

a)         Except during pressure releases, each pressure relief device in gas/vapor service must be operated with no detectable emissions, as indicated by an instrument reading of less than 500 ppm above background, as measured by the method specified in Section 721.963(c).

b)         Actions following pressure release.

1)         After each pressure release, the pressure relief device must be returned to a condition of no detectable emissions, as indicated by an instrument reading of less than 500 ppm above background, as soon as practicable, but no later than five calendar days after each pressure release, except as provided in Section 721.959.

2)         No later than five calendar days after the pressure release, the pressure relief device must be monitored to confirm the condition of no detectable emissions, as indicated by an instrument reading of less than 500 ppm above background, as measured by the method specified in Section 721.963(c).

c)         Any pressure relief device that is equipped with a closed-vent system capable of capturing and transporting leakage from the pressure relief device to a control device as described in Section 721.960 is exempt from the requirements of subsections (a) and (b).

(Source:  Added at 40 Ill. Reg. 11367, effective August 9, 2016)