Tenn. Comp. R. & Regs. 1200-03-18-.28 - PETROLEUM LIQUID STORAGE IN EXTERNAL FLOATING ROOF TANKS

(1) Applicability of this rule is as follows:

(a) This rule applies to any petroleum liquid storage tank that is equipped with an external floating roof and that has a capacity greater than 150,000 liters (L) (40,000 gallons [gal]).

(b) This rule does not apply to any petroleum liquid storage tank that:

1. Is used to store waxy, heavy pour crude oil;

2. Has a capacity less than 1,600,000 L (420,000 gal) and is used to store produced crude oil and condensate prior to lease custody transfer;

3. Contains a petroleum liquid with a maximum true vapor pressure less than 10.5 kiloPascals (kPa) (1.5 pounds per square inch atmospheric [psia]) provided that records are kept consistent with Subparagraph (4)(b) of this rule;

4. Contains a petroleum liquid with a maximum true vapor pressure less than 27.6 kPa (4.0 psia); and

(i) Is of welded construction, and

(ii) Presently possesses 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 as a revision to the State Implementation Plan; or

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

(2) For the purpose of this rule, the following definitions apply:

(a) "Liquid-mounted seal" means a primary seal mounted in continuous contact with the liquid between the tank wall and the floating roof around the circumference of the tank.

(b) "Vapor-mounted seal" means a primary seal mounted so there is an annular vapor space underneath the seal. The annual vapor space is bounded by the bottom of the primary seal, the tank wall, the liquid surface, and the floating roof.

(c) "Waxy, heavy-pour crude oil" means a crude oil with a pour point of 10°C (50°F) or higher as determined by the American Society for Testing and Materials Standard D97-66, "Test for Pour Point of Petroleum Oils".

(3) No owner of a petroleum liquid storage vessel subject to this rule shall store a petroleum liquid in that tank unless:

(a) The tank has been fitted with:

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 that controls VOC emissions with an effectiveness equal to or greater than a seal required under Part 1 of this subparagraph and is approved as a revision to the State Implementation Plan.

(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

3. For vapor-mounted primary seals, the accumulated area of gaps exceeding 0. 32 centimeters (cm) (0.125 inches [in]) in width between the secondary seal and the tank wall shall not exceed 21.2 square centimeters per meter (cm² /m) (1. 0 square inches per foot [in² /ft]) of tank diameter, as determined by the method in Paragraph (6) of this rule.

(c) All openings in the external floating roof, except for automatic bleeder vents, rim space vents, and leg sleeves, are:

1. Equipped with covers, seals, or lids in the closed position except when the openings are in actual use; and

2. Equipped with projections into the tank that remain below the liquid surface at all times.

(d) Automatic bleeder vents are closed at all times except when the roof is being floated off or being landed on the roof leg supports.

(e) Rim vents are set to open when the roof is being floated off the leg supports or at the manufacturer's recommended setting.

(f) Emergency roof drains are provided with slotted membrane fabric covers or equivalent covers which cover at least 90 percent of the area of the opening.

(4) The owner or operator of a petroleum liquid storage tank with an external floating roof subject to this rule shall:

(a) Perform routine inspections semi-annually in order to ensure compliance with Paragraph (3) of this rule (the inspections shall include a visual inspection of the secondary seal gap); and

(b) Measure the secondary seal gap annually in accordance with Paragraph (6) of this rule when the floating roof is equipped with a vapor-mounted primary seal.

(5) Recordkeeping requirements apply as follow:

(a) The owner or operator of any petroleum liquid storage tank with an external floating roof subject to this rule shall maintain the following records for at least 3 years and shall make copies of the records available to the Technical Secretary upon request:

1. Records of the types of volatile petroleum liquids stored;

2. Records of the maximum true vapor pressure of the liquid as stored; and

3. Records of the results of the inspections performed in accordance with Paragraph (4) of this rule.

(b) The owner or operator of a petroleum liquid storage vessel with an external floating roof exempted from this rule by Part (1)(b)3, but containing a petroleum liquid with a true vapor pressure greater than 7.0 kPa (1.0 psi), shall maintain the following records for at least 3 years and shall make copies of the records available to the Technical Secretary upon request:

1. Records of the average monthly storage temperature;

2. Records of the type of liquid stored; and

3. Records of the maximum true vapor pressure for all petroleum liquids with a true vapor pressure greater than 7.0 kPa (1.0 psia).

(c) The Technical Secretary may, upon written notice, require more frequent inspections or modify the monitoring and recordkeeping requirements, when necessary to accomplish the purposes of this regulation.

(6) Compliance with Part (3)(b)3 of this rule shall be determined by:

(a) Physically measuring the length and width of all gaps around the entire circumference of the secondary seal in each place where a 0.32 cm (0.125 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.

(7) The owner or operator of any facility containing sources subject to this rule shall comply with the requirements in Paragraphs .04(1) and (2) of this chapter.

Notes

Tenn. Comp. R. & Regs. 1200-03-18-.28

Original rule filed May 15, 1979; effective July 10, 1979. Amendment filed March 23, 1981; effective May 7, 1981. Amendment filed April 23, 1992; effective June 7, 1992. Repeal and new rule filed March 8, 1993; effective April 22, 1993.

Authority: T.C.A. §§ 4-5-202 and 68-201-105.