Section 60.692-5 - Standards: Closed vent systems and control devices(a) Enclosed combustion devices shall be designed and operated to reduce the VOC emissions vented to them with an efficiency of 95 percent or greater or to provide a minimum residence time of 0.75 seconds at a minimum temperature of 816 °C (1,500 °F).(b) Vapor recovery systems (for example, condensers and adsorbers) shall be designed and operated to recover the VOC emissions vented to them with an efficiency of 95 percent or greater.(c) Flares used to comply with this subpart shall comply with the requirements of 40 CFR 60.18 .(d) Closed vent systems and control devices used to comply with provisions of this subpart shall be operated at all times when emissions may be vented to them.(e)(1) Closed vent systems shall be designed and operated with no detectable emissions, as indicated by an instrument reading of less than 500 ppm above background, as determined during the initial and semiannual inspections by the methods specified in § 60.696 .(2) Closed vent systems shall be purged to direct vapor to the control device.(3) A flow indicator shall be installed on a vent stream to a control device to ensure that the vapors are being routed to the device.(4) All gauging and sampling devices shall be gas-tight except when gauging or sampling is taking place.(5) When emissions from a closed system are detected, first efforts at repair to eliminate the emissions shall be made as soon as practicable, but not later than 30 calendar days from the date the emissions are detected, except as provided in § 60.692-6 .