What is a method for checking for a leak without using a meter as indicated in NFPA 54 C.3?

The method for checking for a leak without using a meter, as indicated in NFPA 54 C.3, is to inject a soap solution. This technique involves applying a soap and water mixture to suspected leak areas. If there is a gas leak, bubbles will form in the soap solution, alerting you to the presence of gas escaping from the system. This method is effective because it provides a visual indicator of gas leaks and is simple to implement without the need for specialized instruments.

While using a manometer or pressure gauge also can help assess systems for leaks, it doesn't fall under the method that NFPA 54 C.3 describes for directly identifying gas leaks through a physical check. Listening for hissing sounds and observing for gas odors are practical approaches; however, they may not always provide conclusive evidence of a leak compared to the soap test, which offers clear visual confirmation. Thus, the soap solution method is widely accepted as a reliable practice for leak detection in LP gas systems.