(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.