Journeyman Plumber ExamFixtures, Faucets, and Other AppliancesMedium
A plumber is installing a water heater in a utility closet. The water heater is equipped with a temperature and pressure relief (T&P) valve. The discharge pipe from the T&P valve must terminate in a specific manner to prevent hazards. Which of the following is the correct termination requirement for a T&P valve discharge pipe?
- ATerminate outdoors, pointing upwards, to prevent debris entry.
- BTerminate into a clothes washer standpipe.
- CTerminate within 6 inches of the floor or fixture served, indirectly to the drainage system.
- DTerminate in a capped tee fitting for future expansion.
Show answer & explanationAnswer & explanation
Correct answer: C. Terminate within 6 inches of the floor or fixture served, indirectly to the drainage system.
T&P valve discharge pipes must terminate indirectly to the drainage system to prevent backpressure and allow for observation of discharge. They must also terminate within 6 inches of the floor or fixture served to prevent scalding and property damage.
Why the other options are wrong
- A. Terminating outdoors pointing upwards would create a scalding hazard and allow debris/insects to enter the pipe.
- B. Terminating into a clothes washer standpipe is generally prohibited due to potential for backflow, overflow, or scalding.
- D. Capping the discharge pipe would prevent it from functioning, creating a dangerous condition.
T&P Valve Discharge Termination
The specific requirements for how the discharge pipe from a temperature and pressure relief valve must end to safely release hot water or steam.
- Must discharge indirectly to the drainage system.
- Must terminate within 6 inches of the floor or fixture served.
- Must not be capped, plugged, or have valves installed in the line.
- Prevents scalding, water damage, and allows for visual inspection of discharge.
Memory trick: The T&P discharge must be seen, safe, and indirect, like a careful release.