CSLB C-36 Plumbing ContractorRough-in PlumbingMedium
A plumber is preparing to conduct an air test on a new DWV system rough-in. The system consists of 3-inch PVC piping. What is the minimum air pressure that must be maintained in the system for at least 15 minutes during the test?
- A3 psi
- B2 psi
- C5 psi
- D10 psi
Show answer & explanationAnswer & explanation
Correct answer: C. 5 psi
According to the California Plumbing Code (CPC), DWV systems tested with air must be subjected to a minimum pressure of 5 psi for at least 15 minutes. This pressure is sufficient to detect leaks without overstressing the piping system.
Why the other options are wrong
- A. 3 psi is below the minimum required pressure for an air test.
- B. 2 psi is generally too low for an effective air test on a DWV system.
- D. 10 psi is a higher pressure than required and may not be necessary, though it would still reveal leaks.
DWV Air Test
A method of testing a drain, waste, and vent system rough-in using compressed air to detect leaks, typically required before enclosing walls.
- Alternative to water test, especially in cold climates or when water is unavailable.
- Requires a pressure gauge and air compressor.
- Code specifies minimum pressure and duration.
Memory trick: DWV air test, put it to the stress, 5 psi, 15 minutes, put leaks to the test.