Is copper more quiet than pvc?

[sparks98]

I must have a section of 3" drain pipe, about 9 feet, that will be coming from the upstairs bathroom exposed in the living room. I may end up boxing it in later. Cast is just too heavey for me to support properly, so I'll have that exposed section in copper or pvc. Is copper ANY quiter that pvc at all or should I just keep the whole run in pvc?

[Gary Swart]

I don't know for sure if there would be any difference, but either one will be somewhat of a PITA. Since you will be boxing it in, I would suggest you fill the box with insulation. I would look into possibly using the foam cans. This stuff expands, so you would have to allow for that, but it would help with the noise. I'd try to allow for the expansion so as not to have too much excess. You can trim off excess easily after it dries, just mask off walls, floors, etc. It's a bit messy to use, but latex gloves will help. Fiberglass insulation would also work pretty well, but not as well as the foam. Just some thoughts that might give you some ideas.

[master plumber mark]

I know that copper is louder than pvc.

if youi get the FOAM CORE type pvc it certanly is quiter than the copper.


I got abathroom above my kids room in copper and it sounds like a train rushing by when you flush the toielt.

Also if yoiu try to keep whatever youi use from touiching the joists or any lumber along this section it will keep it quieter. they all will transfer sound if they are touiching the wood.

[sparks98]

What is this Foam Core Type pvc?

[Clayton]

PVC is available in a composite pipe made up of at least 3 layers extruded together to form a pipe. A thin solid PVC layer on the inside and outside with the majority of the wall thickness made up of a PVC foam sandwiched between the two layers. Some manufacturers us a non-PVC foam core.
Some benefits of the foam core pipe would be that it is much lighter for ease of handling and shipping and uses less raw materials which all bring down the cost, and it is somewhat more rigid and also quieter. The Cons are that the product is not as strong as its solid wall counterpart and therefore is not approved for all the same applications.

ABS is also available in a foam core type composite pipe.

[dimprov]

I know that copper is louder than pvc.

if youi get the FOAM CORE type pvc it certanly is quiter than the copper.


I got abathroom above my kids room in copper and it sounds like a train rushing by when you flush the toielt.

Also if yoiu try to keep whatever youi use from touiching the joists or any lumber along this section it will keep it quieter. they all will transfer sound if they are touiching the wood.

1. Where does one get foam core PVC? It sounds like a specialty item.
2. How do you keep it from touching the joists or any lumber? Hang it with straps? What kind? The toilet itself sits on 3/4" plywood, so there's no way to isolate the PVC from touching that--or is there? Maybe an elastomeric gasket?

I know that cars use thick elastomeric stuff to reduce road noise inside the cabin. It turns the sound/vibrational energy into negligible heat, basically like a shock absorber. Is there anything like this that's applicable to silencing noisy PVC toilet drain pipes?

This morning I removed the drywall from the ceiling that's underneath the toilet drain pipe, and the 3 inch PVC pipe is on full display. Now is a perfect opportunity to make it quiet.

David

[master plumber mark]

if you have 3 inch pvc already it might just be as well
to cram a bunch of pink insulation under and around that pipe.....

I dont know if it is really worth all the trouble to cut out
perfectly goood pvc to do this..

foam core is quieter, but not that much quieter that you
would want to go to all the trouble.


you can get foam core at any legit plumbing supply house

[jadnashua]

Well, cast iron is a lot quieter than any plastic pipe. Pipes make noises for several reasons: expansion and contraction - rubbing on tight joints, and vibrating as stuff flows through them. CI doesn't expand and contract as much as plastic and because of its weight, doesn't transmit as much noise. Stuffing the joist bay with fiberglass will help a little...foam maybe more, but future maintenance would be a major pain. 5/8" drywall is quieter than 1/2". Two layers even more. Adding noise isolation strips to the drywall installation might help. Or, (it's quite costly), you can buy a composite drywall panel that has a layer of lead in the middle (it's used in high-end home theater and to help in a high security conference room).

[dimprov]

I'm moving the toilet a few feet anyway, so the foamcore is an option.

For the quietest accoustics, what's the ideal way to support/hang it? Version 1.0 was supported by a combination of wooden blocks and metal pins. I suspect that noise conduction plays a non-trivial factor.

I may use Quietrock when I redo the demo'd portion of the ceiling. I'm not planning to put it everywhere, however, so that's another reason to limit the sound conduction.

Any advice appreciated.

David

[dimprov]

For instance, maybe a viscoelastic coating like this:

http://www.quietsolution.com/html/quietcoat.html

could be applied to the toilet drain pipes to good effect?

David

[dimprov]

I took a closer look, and it's actually a NAIL that's partially supporting the drain. The nail is supporting one side, and the wooden block the other.

Is this common? It apparently works, but it doesn't look very comfortable for the pipe.

Anyway, I'd still like to know what the best way of supporting piping is from a sound-proofing point of view. Any input on that would be appreciated.

e.g. is there an isotrax, as it were, for piping? And if there were, would it make a difference in reducing plumbing noise? Please let me know if I'm running down a blind alley.

David

[jadnashua]

When you drain hot water through a pvc pipe (say from a shower, sink, tub, etc.), the heat causes the pipe to expand quite a bit. Anything touching the pipe can cause a noise as the pipe expands across it. Then, as it cools, it contracts, so you get it twice. Supporting it, routing it, and designing a good installation can minimize sounds. This type of expansion/contraction can be squeaks, pipes, clicks, etc. as the pipe moves, depending on whether it is held tight and 'jumps' once it overcomes the friction. A well designed installation means it can expand and contract without rubbing on something that will make noise.