D.C. Mun. Regs. r. 20-703
The loading of volatile organic compounds or gasoline into any tank truck, trailer, or railroad tank car from any loading facility shall be prohibited unless the loading facility is equipped with a vapor collection and disposal system or its equivalent designed to collect the total organic compound vapors displaced during loading and in good working order and in operation.
A loading procedure effected through the hatches of a tank truck, trailer, or railroad tank car with a loading arm equipped with a vapor collecting adaptor, a pneumatic hydraulic, or other mechanical means shall be provided to force a vapor-tight seal between the adaptor and the hatch. A procedure shall be provided to prevent liquid drainage from the loading device when it is removed from the hatch of any tank truck, trailer, or railroad tank car, or to accomplish complete drainage before removal.
When loading is effected through means other than hatches, all loading and vapor lines shall be equipped with fittings which make vapor-tight connections and which close automatically when disconnected.
The vapor disposal portion of the system shall limit the emissions to the atmosphere to no more than eighty (80) milligrams of total organic compounds per liter of product loaded and shall consist of one (1) of the following:
Compliance with or violation of the emission standards in § 703 shall be determined in accordance with the procedures prescribed in Appendix A of "Control of Hydrocarbons from Tank Truck Gasoline Loading Terminals," published by EPA, October 1977, publication numbers EPA-450/2-77-026 and OAQPS No. 1.2-082.
The vapor collection and liquid loading equipment shall be designed and operated to prevent gauge pressure in the delivery tank from exceeding eighteen inches (18 in.) of water column during product loading.
No pressure-vacuum vent in the vapor collection and disposal system shall begin to open at a system pressure less than eighteen inches (18 in.) of water column.
D.C. Mun. Regs. r. 20-703