CSLB C-36 Plumbing ContractorRough-in PlumbingMedium
A plumber is performing a final pressure test on a newly installed potable water supply system. The system is to be tested with air. According to the California Plumbing Code (CPC), what is the minimum air pressure that the system must be subjected to, and for what minimum duration?
- A100 psi for 15 minutes
- B50 psi for 15 minutes
- C80 psi for 30 minutes
- D125 psi for 30 minutes
Show answer & explanationAnswer & explanation
Correct answer: B. 50 psi for 15 minutes
For potable water supply systems, the California Plumbing Code (CPC) allows for testing with air pressure. The minimum requirement is 50 psi, maintained for at least 15 minutes, with no perceptible loss of pressure.
Why the other options are wrong
- A. 100 psi for 15 minutes exceeds the minimum pressure requirement.
- C. 80 psi for 30 minutes is a more stringent test, but not the minimum required by code for this application.
- D. 125 psi for 30 minutes is typically associated with drainage, waste, and vent (DWV) system air tests, not potable water supply.
Potable Water Air Test
A method of pressure testing a potable water supply system using compressed air to verify its integrity and detect leaks before permanent operation.
- Verifies system integrity against leaks.
- Uses air pressure at a specified level.
- Maintained for a minimum duration without pressure drop.
Memory trick: Water needs 'Fifty' for 'Fifteen' to be free of leaks.