jar546
Forum Coordinator
Is there an exception that precludes the use of hammer arrestors when using PEX or other similar tubing for water supply to quick close valves?
A water hammer arrestor is not for expansion. It is to stop velocity. The PEX would not expand to absorb that force.There is no exception, that I can find, in the Code. But both the California and International plumbing codes say the Water-hammer arrestors shall be installed in accordance with the manufacturer's instructions.
IMHO, there is no need due to the expansion capabilities of PEX. But that is not Code.
When a valve closes quickly and stops the flow, that momentum shakes and pounds pipes, through pressure. The PEX will absorb that force.A water hammer arrestor is not for expansion. It is to stop velocity. The PEX would not expand to absorb that force.
I'm not arguing that a flexible pipe can't handle the movement from water hammer. I'm arguing that the expansion capabilities of PEX will not stop water hammer from happening. Different discussions. Stopping water hammer from occurring or tolerating the movement from water hammer.When a valve closes quickly and stops the flow, that momentum shakes and pounds pipes, through pressure. The PEX will absorb that force.
Still best to have the arrestor at the quick acting valve; after all, water hammer is caused by the sudden change in velocity of the water. A pressure tank will often be a significant distance from the quick acting valve, so it will provide limited, if any, benefit.Most homes in my area have wells. Is there an exception that precludes the use of hammer arrestors when using a pressure tank when you have quick closing valves?
Most homes in my area have wells. Is there an exception that precludes the use of hammer arrestors when using a pressure tank when you have quick closing valves?
Might be so in Cali.....but good luck with that elsewhere.3-19-20: California Plumbing Code section 609.10 is not adopted by the state agency, HCD1 and 2, which is the code of the hammer arrestor. See the Division I administrative section,1.8.2.1.1 in the code for that language as to who adopts or does not adopt certain sections. For those who want the short answer, not required in residential units containing sleeping accommodations, unless your jurisdiction has adopted it and registered that with the state.
Exspansion tanks nor pressure tanks a designed to control the absorbtion of the velocity of the water. Hammer arestors are of a specific designe to absorb the shock and are location specific to function correctly.I'm not aware of that exception.