(Adopted 12/14/1993)

A. Applicability

This rule applies to degassing of any above-ground stationary tank, reservoir, or other container of more than 40,000 gallons (952 bbl) capacity containing any organic liquid having a vapor pressure of more than 2.6 psia or between 20,000 gallons (476 bbl) and 40,000 gallons (952 bbl) capacity storing any organic liquid having a vapor pressure of 3.9 psia or greater at oilfields and pipeline stations. It also applies to degassing of underground tanks with a capacity greater than 500 gallons storing liquids having a vapor pressure greater than 3.9 psia.

B. Exemptions

C. Definitions

See Rule 102 for definitions not restricted to interpretation of this rule.

"Alternate test method" A new method for testing that is not referenced in this rule or which involves major changes to a referenced test method.

"bbl" means barrel, a unit of volume equal to 42 US gallons.

"Degassing" is the process of removing organic gases from a stationary tank, reservoir, or other container.

"Liquid Balancing" is a process in which an organic liquid having a vapor pressure subject to this rule is replaced in a floating roof tank by a liquid with a vapor pressure that is not subject to this rule. This is done by removing as much liquid as possible without landing the roof on its internal supports, pumping in the replacement liquid, allowing mixing, removing as much mixture as possible without landing the roof, and repeating these steps until the vapor pressure of the mixture is not subject to this rule.

"Liquid Displacement" is a process by which the headspace vapors that would be released to atmosphere (i.e. by opening of the fixed roof tank after removal of the liquid contents) are reduced by at least 90% by weight through the use of a displacing liquid to push headspace vapors into control equipment, a make up gas to replace vapors during the emptying stroke, and prevention of the return of the displaced vapors into the tank. The displacing fluid may be produced water or a lower volatility liquid that absorbs vapors. The make up gas may be field gas or a non-ROC gas. The steps of the procedure shall be specified in the plan required by Section G of this rule.

"Underground storage tank" means any one or combination of tanks, including pipes connected thereto, which is totally beneath the surface of the ground. Underground tanks do not include those specified as exemptions in California Health and Safety Code Section 25281(x).

"Vapor pressure": The vapor pressure measured as described in Section E.5 of this rule.

D. Requirements -- Emission Reduction


E. Requirements -- Calculations and Compliance Methods

F. Requirements - Monitoring and Recordkeeping

G. Requirements - Reporting

Tank operators shall submit to the District for approval a plan consisting of the list of above-ground tanks with the respective volumes and vapor pressures of the liquid stored in the tanks, and the control measure(s) that will be adopted to comply with the requirements of this rule.

H. Compliance Schedule