How is test pressure for plumbing systems measured?

Test pressure for plumbing systems is measured in pounds per square inch (psi) because psi quantifies the amount of pressure exerted by a fluid within the plumbing system. This measurement is crucial during the testing phase to ensure that the system can withstand operational pressures without leaking or failing. The use of psi allows plumbers to evaluate the integrity and safety of the system under pressure, which is essential for compliance with plumbing codes and standards.

Other measurement units listed, such as gallons per minute, are used to measure flow rates, not pressure. Degrees Fahrenheit pertains to temperature, which is not relevant in this context, and cubic feet per second is another flow rate measurement that does not apply to pressure testing in plumbing systems.