question about attic supply line

In my attic I have 3 places that the hot and cold lines end. One of these ends just does a 90 degree bend and drops to the kitcken. The other two have a T on the end, one side drops to a bathroom the other side goes up about 18 in and is then capped off.


what are the little risers for?


i hope that was clear as mud. I have included a few picture below.....


water supply line
-------------------------
..................................l
..................................l drop down to kitcken
..................................l



......................................l
......................................l riser that has a cap on it (~18in tall)
water supply line................l
----------------------------
......................................l
......................................l
......................................l drop down to bathroom sink
......................................l
......................................l

My guess is it was an attempt to stop water hammer.

That riser is old school thoughts on preventing hammer situations. It quickly becomes useless. Sticking up in the attic, I hope you don't have freezing problems...

If you want to do something that actually works long term, you could install a proper hammer arrestor, but in reality, if you need one at all, it should be closer to where it is needed. Typical locations in a kitchen would be for an ice-maker or the dishwasher...those both have a valve that can close quickly, not giving the water a chance to adjust the flow, therefore having more energy to slam a pipe when the flow stops (think hitting a brick wall verses a normal stop in your car - a hammer arrestor is sort of like an airbag).