In addition to the definitions contained in 75-11-302, MCA, the following words, phrases, or terms shall have the following meaning in this chapter, unless the context indicates otherwise:

(1) "Aboveground storage tank system" or "AST" means any one or a combination of tanks used to contain an accumulation of petroleum or petroleum product that is 90% or more above the soil surface.   AST includes integral piping located aboveground and petroleum storage tanks located in an enclosed liquid/vapor-tight vault or "special enclosure" designed and constructed in accordance with section 5202.3.6 of the Uniform Fire Code or a "listed" fire protected aboveground storage tank assembly which complies with Uniform Fire Code Appendix II-F.

(2) "Cathodic protection" means the prevention of corrosion of a metallic surface by making that surface the cathode of an electrochemical cell through the use of galvanic anodes, impressed currents, or other similar methods.

(3) "Compatible" means certified as adequate and safe for the storage and delivery of petroleum products by a nationally recognized independent laboratory or organization competent to provide such certification.

(4) "Corrosion expert" means a person with knowledge of physical sciences and principles of engineering and mathematics acquired through education and related practical experience who is qualified to engage in the control of corrosion on buried or submerged metal piping systems and metal tanks and is either accredited or certified by the national association of corrosion engineers or a registered professional engineer certified or licensed to conduct corrosion control of buried or submerged metal piping systems and metal tanks.

(5) "Department" means the department of environmental quality.

(6) "Double-walled tank system" means a petroleum storage tank and associated piping designed and constructed with rigid inner and outer walls separated by an interstitial space that is monitored for a release.

(7) "In contact with the soil" means a portion of a tank or integral piping physically touched by soil or separated from the soil by only a casing, wrapping, or a pervious structure.

(8) "Integral piping" means all continuous, on-site piping until the union of the piping and dispensing equipment and all other valves, elbows, joints, flanges, and flexible connectors attached to a petroleum storage tank system through which petroleum or petroleum product flows.

(9) "Liner" means an impervious material used as a method of secondary containment to prevent a release of any petroleum or petroleum product from a petroleum storage tank system.   The defined term does not include interior tank linings or exterior tank coatings.

(10) "Overfill" means a release of petroleum or petroleum product that occurs when an aboveground tank is filled beyond maximum capacity.

(11) "Petroleum storage tank" means a tank that contains or contained petroleum or petroleum product and that is:

(a) an aboveground storage tank situated in an underground area such as a basement, cellar, mine, drift, shaft, or tunnel;

(b) an aboveground storage tank situated inside a vault or special enclosure as set forth in section 5202.3.6 and Appendix II-F of the Uniform Fire Code;

(c) an aboveground storage tank with a capacity of less than 30,000 gallons; or

(d) aboveground pipes associated with tanks under (a) -(c) of this definition, except pipelines regulated under the following laws:

(i) the Natural Gas Pipeline Safety Act of 1968 (49 USC 1671, et seq.) ;

(ii) the Hazardous Liquid Pipeline Safety Act of 1979 (49 USC 2001, et seq.) ; and

(iii) state law comparable to the provisions of law referred to in (i) and (ii) above.

(12) "Pipe" means any hollow cylindrical or tubular conveyance constructed of approved non-earthen materials (e.g., cathodically protected metal, plastic or fiberglass) through which petroleum and petroleum product is designed to flow.   No nonmetallic pipe shall be installed aboveground unless provided with 2 hours of fire protection.

(13) "Release detection" means a method of detecting whether a release of petroleum or petroleum product occurred from the petroleum storage tank system into the environment or into the secondary containment.

(14) "Rigid" means an intrinsic characteristic which allows a material to maintain a pre-formed shape or configuration without internal or external support.

(15) "Secondary containment" means any approved system used to provide release detection and release prevention.   Examples of secondary containment include an approved double-walled tank, an approved double-walled integral piping system, or an approved single-walled tank or integral piping system that is protected by an enclosed concrete vault or special enclosure as required by the uniform fire code.

(16) "Shop-fabricated storage tank" means a listed storage tank constructed at the tank manufacturer's plant according to approved standards and accepted engineering principles and transported to the facility for installation.

(17) "Storage tank system" means an approved aboveground petroleum storage tank and all associated integral piping and release detection components.

(18) "Tank" means an enclosed aboveground stationary device, no more than 10% of which is located beneath the surface of the ground, constructed of approved non-earthen materials that provide structural support and designed to store petroleum or petroleum product.