When is a pressure test usually performed on gas piping?

A pressure test is typically performed on gas piping following installation or modification to ensure the integrity and safety of the system. This testing is crucial as it identifies any potential leaks or weaknesses in the piping that could pose a safety hazard once the gas is put into operation. Conducting the pressure test after the piping has been installed or modified allows for the evaluation of joints, fittings, and the entire system to confirm that all components can withstand the operating pressure of the gas without leakage.

Performing the test after installation or modification ensures compliance with safety regulations and industry standards, which require that all gas piping systems be thoroughly inspected and tested before being put into service. The test must be carried out using appropriate procedures and acceptable methods, typically involving pressurizing the system with a specific medium, such as air or nitrogen, and monitoring for any pressure loss that could indicate a leak.

In contrast, testing before installation would not be effective because there would be no completed system in place to evaluate. Painting the surface or routine maintenance activities pertain to different aspects of gas piping systems and do not relate to the need for a pressure test as a measure of safety before operations commence.