Alternative for pvc

[Baker]

We are trying to build with as little chemical offgasing as we can but don't know alot yet. Just starting to research. We will be using air tubes for ventilation and had thought we would use pvc -easy to work with and readily available. However, yesterday I read that among other problems, it off gases for its entire life. Does any one know of a good alternative - needs to be a least 4", 8" or 12" in diameter.

[hitssquad]

I understand that the PVC-impregnated airforms can be coated to minimize offgassing. Maybe the insides of the airtubes could somehow be coated. Extruded PVA-ECC (ductile concrete) might be an option if you could find someone making pipes out of it.

I would look into using a length of PVC pipe as a form for sprayed-on PVA-ECC. That way you could make your own tubes. The folks on the ferrocement discussion list might be able to help you out in that area:
http://www.ferrocement.net/index.php?inc=2

PVA-ECC expert Richard McCabe is often active on that list. You might title a post "Question for Richard McCabe about making PVA-ECC pipes".

[Ula Oh]

Look into PEX for water piping. I don't think it adds any thing to the water and I don't think it off gasses at all. Plus it is very flexible so you will save money on piecing together bends in the pipe. The inside is incredibly smooth (which allows for more water flow) so you can use a smaller diameter pipe, even smaller if you use water saving fixtures.

http://www.google.com/search?q=PEX&clie ... cape:en-US

It would probably work great with grey water systems too!

Ula

[Nick Howes]

FWIW:

I used PEX for water supply.

I used PVC for air ducts, DWV, and electrical conduits. PVC used for pipes and conduits is unplasticized, so it doesn't outgas (much). Most "green building" reports I've seen say unplasticized PVC is "OK" - not great, but not so bad compared with other building materials.

[BWARDEN]

PEX is great stuff. I have it in my radiant floor and most of my domestic water plumbing. Just be aware that some PEX is rated for potable water, and some is not. My radiant floor PEX is not rated for potable water.

The other thing about PEX in domestic water plumbing is that the flexibility of the tubing can cause it to move as you turn water on and off, so it must be firmly fixed in your wall to minimize rattling noises, and possibly tubing wear as it rubs on your wall studs.