All on-ground or underground piping that conveys hazardous substances under pressure must be equipped with an automatic line leak detector which alerts the operator to the presence of a leak by restricting or shutting off the flow of hazardous substances through the piping or by triggering an audible or visual alarm. These devices must detect leaks equivalent to three gallons per hour at 10 PSIG line pressure within one hour with a probability of detection of 95 percent and a probability of false alarm of five percent or less.

All new on-ground and underground piping must be equipped with leak detection equipment capable of detecting leakage between the piping and the secondary containment system.