What is the recommended method for testing a gas piping system for leaks?

The recommended method for testing a gas piping system for leaks involves filling the system with air or an inert gas and checking for bubbles. This technique is effective because it allows for the detection of even small leaks. When the system is pressurized, any escape of the testing medium will create bubbles at the point of a leak, providing a visible indication of where the problem lies. This method not only assures safety but also is a widely accepted practice within the industry, following guidelines and standards to ensure the integrity of the gas piping system.

The other methods listed do not adequately ensure safety or effectiveness in detecting leaks. For instance, filling the pipe with water may miss gas leaks entirely if the leak is above the waterline, leading to potential hazards. Applying sand around the joints does not provide a reliable means of detecting leaks, as it cannot reveal the presence of gas escaping from the system. Using a gas detector with a flame can also be very dangerous, as it introduces a risk of igniting any gas present during the testing process. Therefore, the most reliable and safest approach remains the method of using air or an inert gas and looking for bubbles.