(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) automatic line leak detectors, which include methods that 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 and an annual test of the operation of the leak detector is conducted in accordance with ARM 17.56.401. If an automatic line leak detector fails the annual test at 3.0 gallons per hour at 10 pounds per square inch line pressure within 1 hour, it must be replaced;
(b) line tightness testing, including 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
(c) tank methods designed to detect a release from any portion of the underground piping that routinely contains regulated substances. These methods include those set forth in ARM 17.56.407(1)(e) through (i) and (2).
(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 system, existing prior to November 26, 2009, employing piping interstitial monitoring as the primary leak detection method pursuant to this chapter shall meet the requirements of ARM 17.56.306(3) and ARM 17.56.204.
(4) UST systems installed, modified, or replaced after November 26, 2009, must employ piping interstitial monitoring and meet the requirements in ARM 17.56.306(3) and ARM 17.56.204.