(1) All aboveground double-walled petroleum storage tank systems owned or operated by persons that want to qualify for a reduced deductible allowed by the statutes and rules governing the Montana petroleum tank release cleanup fund must be designed and constructed in accordance with the following standards:

(a) Aboveground petroleum storage tank systems shall consist of either shop-fabricated double-walled storage tanks or petroleum storage tanks installed in a vault or special enclosure as required by UFC 5202.3.6 and Appendix II-F (these assemblies may be referred to in this rule as "protected systems") , and any integral double-walled piping shall meet the requirements of this section at the time of construction and installation.

(b) Storage tank systems must be constructed of materials that are compatible with the petroleum product stored in the system.

(c) In addition to secondary containment as required by (1) (i) of this rule, petroleum storage tanks must be designed and constructed to meet any of the following standards:

(i) aboveground storage tanks constructed of steel shall meet or exceed the requirements of UL No. 142, API Standard No. 620, API Standard No. 650, API Standard No. 12D or API Standard No. 12F;

(ii) aboveground storage tanks constructed of materials other than steel must not be installed unless such materials have received the written approval of the department of justice fire prevention and investigation bureau.   Where required (e.g., "Motor Vehicle Fuel-Dispensing Stations") , protected systems must be listed in UL 2085, UFC Standard 79-7, the southwest research institute (SwRI) , or any other testing agency approved by the state fire marshal.

(d) Tanks must be located and supported in accordance with the requirements of Uniform Fire Code Articles 52, 79 and Appendix II-F.

(e) The bottom of metal tanks that rest on or within the soil must be cathodically protected with sacrificial anodes or an impressed current system designed, constructed and installed in accordance with API RP 651 and NACE Standard Number RP-0285-95, and:

(i) a corrosion expert must design and supervise the installation of impressed current cathodic protection systems;

(ii) each cathodic protection system must have a test station or a monitoring method that enables the owner or operator to ensure cathodic protection.

(f) Exterior coatings must be designed and applied to storage tank systems to prevent corrosion and deterioration and to protect against degradation by ultraviolet light.

(g) All integral piping, including bulk product piping and hydrant piping, must be constructed with secondary containment as provided in (1) (i) of this rule.   All integral piping systems must be constructed in accordance with accepted engineering principles and Uniform Fire Code Articles 52, 79 and Appendix II-F.   Integral piping must be constructed of one or more of the following materials and in accordance with the following standards:

(i) cathodically protected coated steel in accordance with UFC Article 79, API RP 1615, API RP 1632, NACE RP-0169-83 and NACE RP-0285-85 or STI R892-89;

(ii) non-metallic pipe (e.g., approved PVC and/or fiberglass) must not be installed as primary aboveground piping unless it satisfies the 2-hour fire protection requirement for tank assemblies in accordance with Uniform Fire Code Articles 52, 79 and Appendix II-F.

(h) Storage tank systems with a capacity of 660 gallons or less used to store heating oil for consumptive use on the premises where stored must be designed, constructed, and installed in accordance with the secondary containment requirements of UFC 7901.8, the Uniform Mechanical Code, NFPA 31, and (1) (i) of this rule.   In addition, installation of such storage tank systems must be completed in accordance with the requirements of all local fire code and building code ordinances.

(i) For the purposes of this chapter, secondary containment of petroleum storage tank systems must be designed and constructed as follows:

(i) Shop-fabricated storage tanks must be designed and constructed with rigid inner and outer walls separated by an interstitial space that is capable of being monitored for a release.   The interstice must be designed to direct any release to a monitoring point or points and must be provided with an emergency vent equal in size to the emergency vent on the primary tank;

(ii) Piping must be designed and constructed with a rigid inner and outer wall separated by an interstitial space that is capable of being monitored for a release.   Primary (i.e., product conveying) piping must be constructed only of approved metallic material;

(iii) Vaults and special enclosures must be designed and constructed in accordance with UFC 5202.3.6 or Appendix II-F, and the owner or operator must submit plans for approval to the department of justice fire prevention and investigation bureau prior to installation; and

(iv) For the purposes of this rule, the use of clay-based composite products, off-site natural clays or synthetic liners does not satisfy the definition of double-walled or secondary containment construction and is strictly prohibited.   Concrete and/or concrete composite material constructed in accordance with accepted engineering principles and listed as a system that provide 2-hour fire protection in accordance with requirements of the uniform fire code, such as vaulted or special enclosure systems, shall satisfy the definition of "double-walled" and "secondary-containment".

(2) Catchment pans and sumps must be installed under dispensers.

(3) Tanks, piping and ancillary equipment must be protected from tampering and damage by fences and barriers.

(4) Tanks with a capacity greater than 1,100 gallons must be equipped with equipment which prevents the tank from being overfilled or a high-level alarm which alerts the transport operator to stop product flow in time to prevent the tank from being overfilled.