27 Jul 2000 at 8:06 pm #273263MasterPlumbersKeymaster
Owner/Builder of a single story ranch house in LA County and curious if the Masters think it would be advantagous if the copper plumbing running through the attic was hung instead of attached to the trusses? I’m about 10 miles from the Mother of all fault lines. I’m trying to build in a little insurance… There will be up to 12 copper lines, from 3/4″ to 1.5″ and the run lengths vary from 10′ to 75′. Hot water for the radiant hydronic heat and cold water for the air-conditioning.
One more question if I may. Why do they hang plumbing in commercial buildings?
PS. There are paid professionals building the house and as far as I know, none of them work at Home DEPOT.
27 Jul 2000 at 10:40 pm #287229
Hi Steve, copper tubing is great for taking vibration and swaying unlike plastic OR screwed piping, especially if the copper is brazed instead of soldered.
About your question “One more question if I may. Why do they hang plumbing in commercial buildings?” On high rise building (42 stories height) the building sway and we have to provide a means to keep undue stress on the pipe (the same as hot water expansion to allow for the coefficient of expansion per degree)
Think about having a storm line or soil stack going up (vertically) over 325 feet the amount of sway the building has having a pipe rigidly connected would cause the joints to give up the ghost without a means of allowing for movement
Even in a one family home provisions should be made off the hot water riser for expansion/contraction like a four fitting swing NOT restricting the movement by clamps anchoring it the studs.
Now since a lot of states do not require a heating person to have any license you can see lots of failures constantly by the “heating contractor” installing copper tubing through metal studs and these folks don’t realize the copper movement will scrape against the metal thus creating a hole. On fin tube especially you can hear the shifting as this piping gets hot and cools.
The proper way of hanging the copper is the key to a long lasting quiet system.
Copper should be supported as follows 11/4 or Less every 6 feet and 11/2 or more every 10 feet.
The use of band iron FORGET ABOUT IT.. Use copper coated clevis hangers or riser clamps (copper coated) Vertically piping should be supported every story height.
If your supporting several pipes close together you can use a trapeze.
For hot water/steam piping you could also use roller (clevis) hangers to allow for movement like we do on commerical and large buildings.
The piping for a shower head should be anchored against a stud so as to prevent this pipe from vibrating AND makes it much easier to replace the shower arm if need be.
You should also try to keep the hot and cold piping seperated by at least 6″ and have a return circulation line installed on all H/W piping over 50′ from the source.
Having a return circulation can help prevent excessive thermo stress on your piping as you don’t get such a drastic temperature change.
By having the return H/W mix with the incoming cold water you save BTU’s as the in coming water doesn’t need as many therms to heat it AND your not putting very cold water into your hot water tank (Less condensation also) PLUS you get the added benefit of almost instant hot water with less waste of water that your not heating water that will just sit in a pipe to cool down as most non circulated homes face.
If you have any more questions please feel free to ask.
One more point IF your also running the H/W in the attic and having it down feed becareful of the temperature of this water. If a leak should occur you certainly do not want anyone scalded so place these pipes as much as possible from harms way.
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