I am building a home and I have heard that I can use either ABS or PVC for my DWV. I have ruled out cast because of the cost. Can anyone give me the pros and cons of ABS & PVC? Which is preferred and why. They seem the same to me. I know some places do not allow ABS, but noone can tell me why.

Thanks,

Brian

Here are the pros and cons.
ABS is easier to work with due to its one step process. You cut it, glue it, and put it together and if you cut it square, it is perfect.
However, ABS is foam core so if you don't glue the end of every piece of pipe less than 1' long, you will get a leak and be unable to pass your pressure test.
ABS also is more flexible than PVC so it will warp in the sun. Proper precautions need to be made to prevent it from being exposed to the sun.

PVC is easy to work with in the same manner as ABS, but if you buy foam core, you will have the same problems. You can buy PVC in solid core. The real problem with PVC is it is a 2 step process. You have to use purple primer before you glue each joint and hub. ABS only needs glue. If you don't use the cleaner, the joints will come apart. The problem with the purple primer, is it is so viscous, it literally gets all over everything and makes the piping look terrible unless you are extreemly carefull. Often times you will end up with purple runns down the white pipe. Many plumbers won't use it because it looks bad when installed.
Finally, PVC must be held together every joint for 7 to 10 seconds, or it will automatically come apart. ABS glues immediately and won't come apart.

So there you have it, these are the real differences. The basic cost is the same for the material, within a few cents, but the labor for PVC is higher than ABS.
Good Luck


Raymond VinZant Plumbing Prof.

Ive read that pvc is also stronger. Is it also rated against pressure and heat(hot water)?

As a master plumber I have found over the past 40 years plastic piping systems are the most expensive systems to be placed in a building where the owner plans on keeping the home.

If I was to work for a get in and get out and never look back type of home builder and had non skilled employees then I would certainly pick plastic over a quality, non carcinogenic material such as cast iron.

Even Charlotte pipe the manufacturer of plastic and CI recommends CI for above ground drainage and waste and soil lines and plastic for venting.

Plastic piping needs proper supports BUT considering the caliper of installer found installing plastic in most cases they use band iron in lieu of clevis hangers which should be spaced much closer then required for CI piping.

I do suggest plastic piping for people with hearing problems as they will not notice the excessive noise and don't mind having a drain cleaning guy available as the short radius fittings do cause a lot more stoppages then a long sweep that is readily available in no hub cast iron.

Every NH CI joint in reality is a possible clean out.

You normally get what you pay for, an example an Americast / cast iron bath tub cost 3 times more then a steel tub thus for those builders interested in cheap as possible low bidder gets the job plastic piping and steel tubs is the way to go.

By the way FYI go on the internet and type in "Toxic plastic" and then ask yourself what are the real qualifications of the so called plumbers who want to install it in your home

http://www.checnet.org/HealtheHouse/education/articles-detail.asp?Main_ID=185