hammer arrestor

I am currently repiping my 1600 sq ft. house with copper. I've also gutted the main bathroom and have installed new valves for all fixtures. Before soldering near the shower and bath valves, I opened them to release air pressure (something I learned on this forum) and discovered that the valves open and close with only a 1/4 turn. When I saw this, I began to wonder about water hammer problems because the valve can be shut down so quickly. Your advice would be greatly appreciated. Here are some factors that may or may not be important. The street supply is 3/4. I reduced to 1/2 at each fixture, keeping the 1/2 to a minimum. The shower and bath valves are two handled things, which appealed to me. To comply with pressure balance concerns, I installed a remote unit under the shower. This unit will serve both the shower and the bath, which are two separate sets of valves.

I am reluctant to put a hammer arrestor in the wall just beneath the valves because they'll be buried under tile. But I can easily put them in the crawl space under the shower, between the valves and the pressure balance unit. That would put the hammer arrestors about 4 or five feet from the shower valves.

I will also be installing a pressure regulating valve for the house.

Given my circumstances, do you think hammer arrestors would be advisable? If so, does each water line to a bathroom fixture get one?

Thanks in advance!

A valve you turn can rarely create a hammer situation. Things like toilet valves, dishwashers, washing machines, ice makers with the electrical solinoid valves can. Most toilet valves are not sources of water hammer, but a few are. So, in this instance, I wouldn't worry about it.

hammer

You could create a water hammer with those valve, but in normal use you won't since you would not normally spin the valve closed as fast as you can. If you have lever handles and "flip" them closed then that could create the hammer, but from your description it seems that you could retrofit arrestors if the need arose. I hope you do not use the two showers at the same time, because that presssure balancer probably has very small internal passages and was intended for one user at a time.

Thank you, Jadnasha and HJ. It doesn't sound like I need to worry so much about this. Yes, HJ... I knew that this unit doesn't have the greatest flow but there won't be much, if any, occassion when both the shower and bath are in use at the same time. Out of curiosity -- are bathtub valves usually pressure balanced? I included the bathtub because logistically it was easy to do and I thought somebody could have their head under the faucet and get scalded. But are dedicated bathtubs usually pressure balanced the way showers are? Thanks again.

All new (in the US anyways) shower valves are pressure balanced, thermostatically controlled, or both. Don't think that that applies to a tub only fixture, but since many of them can be used for a shower as well, most probably are.