701.1 A person shall not place, store or hold in any stationary tank, reservoir or other container with a capacity of more than forty thousand (40,000) gallons any gasoline or any petroleum distillate having a vapor pressure of one and one-half pounds per square inch (1.5 lb./in²) absolute or greater under actual storage conditions, unless the tank, reservoir, or other container is a pressure tank maintaining working pressures sufficient at all times to prevent hydrocarbon vapor or gas loss to the atmosphere, or is designed and equipped with one of the vapor loss control devices in good working order and in operation, as provided in §§ 701.2 through 701.13.

701.2 This section shall apply to all petroleum liquid storage vessels equipped with external floating roofs, having capacities greater than forty thousand (40,000) gallons.

701.3 This section does not apply to petroleum liquid storage vessels which do any of the following:

(a) When used to store waxy, heavy pour crude oil;

(b) Have a capacity of less than four hundred twenty thousand (420,000) gallons and are used to store produced crude oil and condensate prior to lease custody transfer;

(c) Contain a petroleum liquid with a true vapor pressure of less than one and one-half (1.5) pounds psia;

(d) Contain a petroleum liquid with a true vapor pressure less than four (4.0) pounds psia:

(1) Are of welded construction; and

(2) Presently possess a metallic-type shoe, seal, a liquid-mounted foam seal, a liquid-mounted liquid filled type seal, or other closure device of demonstrated equivalence approved by the Mayor; or

(e) Are of welded construction, equipped with a metallic-type shoe primary seal and have a secondary seal from the top of the shoe seal to the tank wall (shoe-mounted secondary seal).

701.4 No owner of a petroleum liquid storage vessel subject to this section shall store a petroleum liquid in that vessel unless the following requirements have been met:

(a) The vessel has been fitted with the following:

(1) A continuous secondary seal extending from the floating roof to the tank wall (rim-mounted secondary seal); or

(2) A closure or other device which controls volatile organic compound emissions with an effectiveness equal to or greater than a seal required under § 701.4(a)(1) and approved by the Mayor;

(b) All seal closure devices meet the following requirements:

(1) There are no visible holes, tears, or other openings in the seal(s) or seal fabric;

(2) The seal(s) are intact and uniformly in place around the circumference of the floating roof between the floating roof and the tank wall; and

1. (3) For vapor mounted primary seals, the accumulated areas of gaps exceeding one-eighth inch (1/8 in.) in width between the secondary seal and the tank wall shall not exceed one inch squared per foot (1.0 in/ft²) of tank diameter, as determined by the method in § 701.12.
2. (c) All openings in the external floating roof, except for automatic bleeder vents, rim space vents, and leg sleeves, are as follows:
3. (1) Equipped with covers, seals, or lids in the closed position except when the openings are in actual use; and
4. (2) Equipped with projections into the tank which remain below the liquid surface at all times.
5. (d) Automatic bleeder vents are closed at all times except when the roof is floated off or landed on the roof leg supports;
6. (e) Rim vents are set to open when the roof is being floated off the leg supports or at the manufacturer's recommended setting; and
7. (f) Emergency roof drains are provided with slotted membrane fabric covers or equivalent covers which cover at least ninety percent (90%) of the area of the opening.701.5 The owner or operator of a petroleum liquid storage vessel with an external floating roof subject to this subtitle shall do the following:- (a) Perform routine inspections semi-annually in order to insure compliance with § 701.4 and the inspections shall include a visual inspection of the secondary seal gap;
8. (b) Measure the secondary seal gap annually in accordance with § 701.4(b)(3) when the floating roof is equipped with a vapor-mounted primary seal; and
9. (c) Maintain records of the types of volatile petroleum liquids stored, the maximum true vapor pressure of the liquid stored, and the results of the inspections performed according to §§ 701.5(a) and 701.5(b).701.6 The owner or operator of a petroleum liquid storage vessel with an external floating roof exempted from this section by § 701.3(c) but containing a petroleum liquid with a true vapor pressure greater than one pound per square inch (1.0 lb/in²), shall maintain records of the average monthly storage temperature, the type of liquid, and the maximum true vapor pressure for all petroleum liquids with a true vapor pressure greater than one pound per square inch (1.0 lb/in²).701.7 Copies of all records under §§ 701.5 and 701.6 shall be retained by the owner or operator for a minimum of two (2) years after the date the record was made.701.8 Copies of all records under this section shall immediately be made available to the Mayor, upon verbal or written request, at any reasonable time.701.9 The Mayor may, upon written notice, require more frequent inspections or modify the monitoring and recordkeeping requirements, when necessary to accomplish the purposes of this section.701.10 The owner or operator of any volatile organic compound source required to comply with § 701.13 shall, at his or her own expense, demonstrate compliance by the methods approved by the Mayor.

701.11 A person proposing to conduct a volatile organic compound, emissions test shall notify the Mayor of the intent to test not less than thirty (30) days before the proposed initiation of the tests so the Mayor may at his or her option observe the test. The notification shall contain the information required by, and be in a format approved by the Mayor.

701.12 Compliance with § 701.4(b)(3) shall be determined by the following:

(a) Physically measuring the length and width of all gaps around the entire circumference of the secondary seal in each place where a one-eighth inch (1/8 in.) uniform diameter probe passes freely (without forcing or binding against the seal) between the seal and tank wall; and

(b) Summing the area of the individual gaps.

701.13 A vapor recovery system shall consist of a vapor gathering system capable of collecting the hydrocarbon vapors and gases so as to prevent their emission to the atmosphere and with all tank gauging and sampling devices gas-tight except when gauging or sampling is taking place.

SOURCE: Section 3 of the District of Columbia Air Pollution Control Act of 1984, D.C. Law 5-165, § 701, 32 DCR 565, 615 (February 1, 1985).