Washington Administrative Code
Title - Northwest Clean Air Agency
500 - REGULATED ACTIVITIES AND PROHIBITIONS
Sec2 580.9 - High Vapor Pressure Volatile Organic Compound Storage in External Floating Roof Tanks

Universal Citation: WA Admin Code 580.9

Current through Register Vol. 24-24, December 15, 2024

580.91 This section shall apply to all VOC storage vessels equipped with external floating roofs, having capacities greater than 150,000 liters (40,000 gallons). Compliance with this section shall be achieved by December 31, 1999.

580.92 This section does not apply to storage vessels that:

580.921 Are used to store waxy, heavy pour crude oil;

580.922 Have capacities less than 1,600,000 liters (420,000 gallons) and are used to store produced crude oil and condensate prior to lease custody transfer;

580.923 Contain a volatile organic compound with a true vapor pressure of less than 10.5 kPa (1.5 psia);

580.924 Contain a volatile organic compound with a true vapor pressure less than 27.6 kPa (4.0 psia), are of welded construction, and presently possess a metallic-type shoe seal, a liquid-mounted foam seal, a liquid-mounted liquid fill type seal, or other equivalent closure device approved by the Control Officer; or

580.925 Are of welded construction, equipped with a metallic-type shoe primary seal and have a shoe-mounted secondary seal.

580.93 It shall be unlawful for any person to store a volatile organic compound in a vessel subject to this section unless the vessel has been fitted with a rim-mounted secondary seal or an equivalent closure device approved by the Control Officer.

580.94 All seals or closure devices required by 580.93 shall meet the following requirements:

580.941 There must be no visible holes, tears, or other openings in the seal or seal fabric;

580.942 The seal shall be intact and uniformly in place around the circumference of the floating roof between the roof and the tank wall; and

580.943 For vapor mounted primary seals, the accumulated area of gaps exceeding 0.32 cm (1/8 inch) in width between the secondary seal and the tank wall shall not exceed 21.2 cm2 per meter of tank diameter (1.0 in 2 per foot of tank diameter).

580.95 All openings in the external floating roof, except for automatic bleeder vents, rim space vents, and leg sleeves shall be:

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

580.952 Equipped with projections into the tank which remain below the liquid surface at all times.

580.96 Automatic bleeder vents shall be closed at all times except when the roof is floated off or landed on the roof leg supports;

580.97 Rim vents shall be set to open when the roof is being floated off the leg supports or at the manufacturer's recommended setting;

580.98 Emergency roof drains shall be provided with slotted membrane fabric covers or equivalent which cover at least ninety percent of the area of the opening.

580.99 Routine inspections shall be performed as follows:

580.991 Conduct a semi-annual visual inspection of the secondary seal gap;

580.992 Measure the secondary seal gap annually if the floating roof is equipped with a vapor-mounted primary seal; and

580.993 Maintain records of the types of petroleum liquids stored, the maximum true vapor pressure of the liquid as stored, and the results of any inspections performed for period of two years after the date on which the record was made.

580.994 A person proposing to measure the seal fit of a storage vessel in order to comply with this section shall notify the Control Officer of the intent to measure not less than five working days before the measurement so the Control Officer may at his option observe the measurement.

580.100 It shall be unlawful for any person to store a volatile organic compound in a vessel with an external floating roof exempted from this section by 580.924, but containing a volatile organic compound with a true vapor pressure greater than 10.5 kPa (1.5 psia) unless records of the average monthly storage temperature, the type of liquid and the maximum true vapor pressure of such liquids are maintained.

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