knocking and shut offs...

[paulhar]

1)
I have a separate shower and bath. I have put piping to prevent knocking for the bathtub. Does a separate shower require the same thing?

2)
If I have shut off valves for the entire bathroom, do I need separate shutoff valvues for my sink?
(Since they are seen under every sink...)

Thanks

[plumber1]

(1)...what do you mean when you say pipes to prevent knocking? shock suppressors? Where did you put them?

(2)...You think they look bad or what?...If you are the guy servicing the bathroom, you would want them. Personally I think that because you need a supply pipe that a small chrome shut-off doesn't detract. So whats your real question?

[paulhar]

1) On the tub - there is a tee connection going into each valve with 1/2 pipe extending up two feet. Perhaps this is fiction but it seems to me that tubs are more prone to knocking than showers.. Is this true?

2) From your reply - it appears that there is no real reason to additional shut offs at the sink...? How is it any more convienent for service?

[prashster]

Separate shutoffs are advisable bkz if you need to disable the sink for several days, the absence of its own shut offs would mean you couldn't use the rest of the bathroom. Hope you can hold it for that long!!!

Those stubs are called hammer arresters. They say (I cannot confirm) that simple stubs of pipe like this eventually fill with water, making them useless in suppressing hammering. "Proper" hammer arresters are sold as such, and I imply by their higher price that there's something in there that prevents them from filling. Can someone confirm?

[plumber1]

" Prashster says: there's something in there that prevents them from filling. Can someone confirm?"

Sounds like they put air chambers behind the tub too. Probably a pipe extension with a cap on top.

[jadnashua]

Hammer arrestors have a bladder or sealed compartment...it is not open to the water where the trapped air can disolve into the water stream over time.

[prashster]

You can keep your simple pipe stubs functioning like good hammer arrestors by draining your houses water supply every couple days and replenishing the air. Doesn't that sound like fun?