ABS vs. PVC DWV

[Spaceman Spiff]

I'm an ex-electrician / commercial architect building my own house. I know a bunch of residential but commercial is definitely my forte.

I specified cast for the vertical stacks, but the other day my plumber offers me a choice between PVC and ABS for all of the other runs. In all of my personal home renovation I've only seen ABS and didn't know PVC was an option. My plumber says it doesn't act like a noodle when it is in the sun for a while and is quieter than ABS.

Could I get some opinions and info so I can make an informed decision, please? I'm not worried about parts availability... the big orange box doesn't carry PVC, but there are numerous plumbing supply houses around.

Thanks!!!

 

[hj]

pipe

IN most areas you do not get the choice. The supply houses in an area usually carry one or the other, with possibly is sprinkling of the alternate material. The pipe in your house is not going to be in the sun so it will not turn into a noodle, and since the pipe walls are the same thickness I doubt there is any material difference in sound transmission. But since the verticals are going to cast iron anyway, sound should not be a factor. This area is one that is all ABS and any drainage problems are usually caused by poor installation, not the pipe material.

 

[Sponsor]

 

[Master Plumber Mark]

pvc sch 40 is the best.

get the pvc sch 40 pipe it is the most
heavy duty you can use......or get the pvc 40 foam core
which is supposed to be quieter ....

also on another note in the Mid West the ABS black stuff
was outlawed years ago because of fire safety issues....
cant even get it around here anymore.

in a fire they found that the pvc would only
smoulder and never really light up
but the Black ABS would light up like a log
and burn for a long time adding to the fire

both put out toxic fumes in a fire, but it was
deemed that the PVC was considered more fire safe.


both cost about the same.

 

[Cal]

Use Pvc ( sch 40 or foam core) it is a MUCH better material then ABS. I am in No.Va. we have several developments that are ABS and I am always over there replacing something! One thing about PVC is that it is more flexable then abs.Abs has a tendency to split at fitting connections if it has some strain on it . Like Mark, I thought ABS had been outlawed .

Good Luck !

 

[Jimbo]

ABS is still the pipe of choice in much of the country. Despite some of the previous posts, I am not aware of scientific evidence that PVC performs better in fires. At one time my job involved getting UL and CSA approvals for consumer electronic products. ABS was the principal material that passed the flammability tests.

Many years ago there were 2 companies making bad ABS. Too much regrind and some other production problems. Class action suits, etc. etc. That is all ancient history now, but of course in certain areas ( AZ was one area) lots of that old stuff is still there, and some split fittings will crop up now and then.

Now, if only we could get Sylvan to chime in.................

 

[DX]

Indeed, in the midwest ABS is only seen in irrigation. Never seen ABS inside a house. Everybody is happy. I am curious as the why cast iron for the vertical runs. I see no reason for the extra expense. If you want quiet, use heavier pipe (like schedule 80) or wrap the pipe. Much cheaper and easier to service/modify later.

 

[Plumguy]

Here in MA the popular choice is pvc, although abs is legal. As far as thickness they are both the same, schedule 40 is schedule 40. Abs is slighty lighter which is why I think pvc is now available in foam core(junk). Abs is twice as much in costs but that could be because it is not the choice of the two and it is harder to find. They both can withstand the same pressure as far testing for inspections. Pvc is more brittle than abs!! Go figure that, with our winters if you drop a pvc fitting it shatters as opposed to abs it breaks evenly. Not that it matters they are both broken.

I don't think there is a major difference between the two as far as the dwv system for you're house. As previously stated the are both very toxic in a fire and are not going to be vulnerable to sunlight. I would go with what is more readily available in you're area. It keeps everybody happy and familiar.

As far as cast iron on the main stacks, that will make a big difference in the noise level of you're system. Insulating pvc cannot compare to CI. It is not uncommon around her to see it done in million dollar plus homes. That is one downside of plastic pipe that while entertaining or dining hearing a toilet flush and drain is not very appealing!