CSLB C-36 Plumbing ContractorRough-in PlumbingHard
A plumbing contractor is installing a new residential water supply system. A water hammer arrestor is required for a quick-closing valve on a washing machine connection. What is the minimum approved type of water hammer arrestor that should be installed?
- AAny type listed in the CPC as an approved device
- BA permanently sealed air chamber type
- CA piston-type with an air chamber
- DA spring-loaded accumulator type
Show answer & explanationAnswer & explanation
Correct answer: A. Any type listed in the CPC as an approved device
The California Plumbing Code (CPC) does not specify a single 'minimum approved type' of water hammer arrestor beyond requiring that it be a listed and approved device. Various types (piston, bellows, permanently charged air chambers, etc.) are acceptable as long as they meet the performance standards of the applicable listing (e.g., ASSE 1010) and are approved for use.
Why the other options are wrong
- B. Permanently sealed air chambers are a type, but again, not the sole 'minimum approved type'.
- C. Piston-type with an air chamber is a common and effective type, but not the only 'minimum approved type'.
- D. Spring-loaded accumulators are a type of arrestor, but not exclusively the 'minimum approved type'.
Water Hammer Arrestor
A device installed in a plumbing system to absorb the shock caused by sudden changes in water flow (water hammer), protecting pipes and fixtures.
- Prevents loud noises and potential pipe damage.
- Required for quick-closing valves (e.g., washing machines, dishwashers).
- Must be a listed and approved device by code.
Memory trick: Water hammer, don't let it bang, any listed device will save the clang.