The standing pressure test for positive pressure medical gas piping shall be conducted with the source valve closed at a test pressure of what percentage above normal system operating pressure for 24 hours?

The standing pressure test for positive pressure medical gas piping is essential to ensure the integrity of the system and to check for any leaks. Conducting this test at a pressure that is 20% above the normal system operating pressure provides a sufficient margin to identify any potential faults within the system without being excessively high, which could potentially damage system components.

This 20% increase ensures that the piping and all associated fittings are tested under conditions that mirror actual operating scenarios while providing an added safety factor. By maintaining this level of pressure for 24 hours, the test allows for a thorough inspection, ensuring reliability and safety in a medical environment where gas leakage could pose significant risks.

The other options present either fixed pressures that don't adjust with system operating pressures or multiplier values that do not conform with the required percentage above the normal operating pressure.