The test pressure for gas piping shall be no less than 1 1/2 times the proposed maximum working pressure, but not less than _____ psig, irrespective of the design pressure.

The test pressure for gas piping needs to ensure the integrity and safety of the system by confirming that it can hold a certain amount of pressure above the maximum working pressure. Testing at a level of no less than 1.5 times the proposed maximum working pressure provides a margin of safety and allows for the detection of leaks or weaknesses in the piping system.

However, regardless of the calculated test pressure based on the maximum working pressure, there is a minimum pressure that must be adhered to ensure effective testing. This minimum threshold is set to ensure that the test is adequate for even lower working pressures. The values outlined in the choices reflect an established standard for minimum test pressures.

In this case, the value of 3 psig is established as a safety requirement. It ensures that regardless of how low the working pressure might be, the system undergoes a test that is sufficiently rigorous. Testing at below this standard could fail to identify potential issues as lower pressures may not reveal the same vulnerabilities as testing under higher pressures.

Thus, the requirement for a minimum test pressure of 3 psig ensures that all gas piping installations are rigorously tested, contributing to overall safety and reliability in gas distribution systems.