Methods of release detection for piping

Each method of release detection for piping used to meet the requirements of subsection 2 of section 33.1-24-08-10 and section 33.1-24-08-31 must be conducted in accordance with the following: 1. Automatic line leak detectors. 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 [11.36 liters] per hour at ten pounds per square inch line pressure within one hour. An annual test of the operation of the leak detector must be conducted in accordance with subdivision c of subsection 1 of section 33-24-08-30. 2. Line tightness testing. A periodic test of piping may be conducted only if it can detect a one-tenth gallon [.38 liter] per hour leak rate at one and one-half times the operating pressure. 3. Applicable tank methods. Except as described in subsection 1 of section 33.1-24-08-31, any of the methods in subsections 5 through 9 of section 33.1-24-08-33 may be used if they are designed to detect a release from any portion of the underground piping that routinely contains regulated substances.