(1) Each method of release detection for piping used to meet the requirements of ARM 17.56.402 must be conducted in accordance with the following:

(a) Methods which alert the operator to the presence of a leak by restricting or shutting off the flow of regulated substances through piping or triggering an audible or visual alarm may be used only if they detect leaks of three gallons per hour at ten pounds per square inch line pressure within one hour;

(b) An annual test of the operation of the leak detector must be conducted in accordance with the manufacturer's requirements. If an automatic line leak detector fails the annual test at 3.0 gallons per hour, it must be replaced or retested at 5.0 gallons per hour. An automatic line leak detector must be replaced if it fails the 5.0 gallons-per-hour test;

(c) A periodic test of piping may be conducted only if it can detect a 0.1 gallon-per-hour leak rate at 1 1/2 times the operating pressure; and

(d) Any of the methods in ARM 17.56.407(1)(e) through (2) may be used if they are designed to detect a release from any portion of the underground piping that routinely contains regulated substances.

(2) After December 31, 2010, if the leak detection monitoring equipment has the capability, an owner or operator of an UST system that conducts pipe leak detection pursuant to ARM 17.56.408(1)(a) or (d) shall set the leak detection console to temporarily disable the pumping system after a failed leak test. An operator may not restart the pumping system until:

(a) an investigation of the UST system alarm condition is conducted in accordance with the leak detection equipment manufacturer's requirements and ARM Title 17, chapter 56, subchapter 5; and

(b) the owner or operator determines that a release to the environment has not occurred.

(3) An owner or operator of an UST who conducts piping interstitial monitoring as the primary leak detection method pursuant to this chapter shall conduct one of the following tests to determine liquid tightness:

(a) hydrostatically test all containment sumps once every three years with liquid for one hour to a height six inches above the highest sump penetration. A passing test must show no liquid loss measured during the testing interval;

(b) vacuum or pressure test containment sumps in accordance with the testing equipment manufacturer's instructions and pass/fail requirements; or

(c) functionally test containment sumps as recommended by the manufacturer of the containment sump.

(4) An owner or operator who conducts a test pursuant to (3) shall report a failed test to the department.

(5) Testing conducted pursuant to (3) must be accomplished by a licensed installer or compliance inspector pursuant to this chapter. Initial sump functional tests at each facility must be conducted prior to December 31, 2012.