| (a) A control device used to comply with §115.541 of this title (relating to Emission Specifications) must meet one of the following conditions at all times when volatile organic compounds (VOC) vapors are routed to the device. (1) The control device must maintain a control efficiency of at least 90% and must be operated in a manner consistent with how the device was operated during the control efficiency demonstration required in §115.544(c) of this title (relating to Inspection, Monitoring, and Testing Requirements). (2) The control device must be a flare that is designed and operated in accordance with 40 Code of Federal Regulations §60.18(b) - (f) (as amended through December 22, 2008 (73 FR 78209)) and is lit at all times when VOC vapors are routed to the flare. (3) The control device must be a recirculation system that does not cause the pressure inside the tank or vessel to increase by more than one inch water pressure above atmospheric pressure at any time during the degassing operation. (4) The VOC concentration at the outlet of the control device must be less than 500 parts per million by volume (ppmv) at 0% oxygen, dry basis, expressed as methane. (b) All VOC vapors must be routed to a control device until the VOC concentration is less than 34,000 ppmv expressed as methane or less than 50% of the lower explosive limit. After one of the conditions has been satisfied, the tank or vessel may be vented to the atmosphere without control for the remainder of the degassing operation, except as specified in §115.544(b)(4) of this title. (c) Degassing equipment must be designed and operated to prevent avoidable liquid or gaseous VOC leaks. (d) When degassing is effected through the hatches or manways of a storage tank, all lines must be equipped with fittings that make vapor-tight connections. (e) When degassing is effected through the hatches of a transport vessel with a loading arm equipped with a vapor collection adapter, then pneumatic, hydraulic, or other mechanical means must be provided to force a vapor-tight seal between the adapter and the hatch. A means must be provided to minimize liquid drainage from the degassing equipment when it is removed from the hatch or to accomplish drainage before such removal. (f) When degassing is effected through the hatches of a marine vessel with a loading arm equipped with a vapor collection adapter, then pneumatic, hydraulic, or other mechanical means must be provided to force a vapor-tight seal between the adapter and the hatch, or a negative pressure inside the cargo tank must be maintained. A means must be provided to minimize liquid drainage from the degassing equipment when it is removed from the hatch or to accomplish drainage before such removal. |
