ABS vs PVC DWV plumbing

[Greg_The_Hammer]

I have been RVing for going on 20 years. Also, I have been involved with residential contracting for quite some time as well. Many years ago, ABS replaced copper as the preferred material for plumbing the drain systems in residences. Then maybe 20 years or so ago, PVC replaced ABS as the preferred material for DWV systems, and is in use everywhere today, EXCEPT in RV's. The RV manufacturers seem to have stuck with ABS for some reason.

Does anyone have knowledge as to the reason they continue to use ABS rather than PVC? Is it less susceptible the vibration rigors of the open road? Is it less prone to rupture from freezing? Is it less brittle when cold? There must be a bona fide reason they don't use PVC, which is much more readily available.

I'm about to replace a ruptured section of ABS with PVC, unless there is a compelling reason not to. Thoughts?

[Harvey51]

We had an ABS elbow crack on a sink drain running several feet down then 7 feet across the RV to the grey water tank. I think it was just too long and too rigid. I replaced with a rubber elbow and have not had any more trouble.

[dougrainer]

OldSoldier53 wrote:
After doing a little research, I am going with PEX for my TT restoration. Took out PVC some of which was broken. All of which was a bad job. Don't know what was there before. It is a 1968. At about $30 for 100 ft and probably the same amount for fittings, seems like a no brainer.

PVC and Copper was common until about 1978-80 for fresh water piping. The problem with PVC (not to be confused with PEX) is, when it froze, it shattered and splintered in long lengths. After 1980, some used Copper and some used Plastic(pex type) for fresh water piping. By 1990, almost all used Plastic tubing. Doug

[OldSoldier53]

After doing a little research, I am going with PEX for my TT restoration. Took out PVC some of which was broken. All of which was a bad job. Don't know what was there before. It is a 1968. At about $30 for 100 ft and probably the same amount for fittings, seems like a no brainer.

[Lantley]

The OP started the thread referring to DWV piping. Drain Waste Vent.
Somehow the the replies are referring to fresh or supply water piping!

Gets confusing when you start mixing the drain and supply piping.
Wouldn't want to shower with black water even if it is piped in pex!

[OldSoldier53]

I am renovating an 14 ft 1968 Chateau TT. Probably had copper in it but that was poorly replaced with PVC. I have removed all the PVC and will be replacing it with PEX. After looking at all the posts and doing a little research of my own, it looks like that is the best bet. It should be easier to install and will last longer.

BTW. It anybody out there has any info on old Chateau trailer, please share. I am most interested to know what make and model the original furnace and fridge were.

Thanks

[OldSoldier53]

I am renovating an 14 ft 1968 Chateau TT. Probably had copper in it but that was poorly replaced with PVC. I have removed all the PVC and will be replacing it with PEX. After looking at all the posts and doing a little research of my own, it looks like that is the best bet. It should be easier to install and will last longer.

BTW. It anybody out there has any info on old Chateau trailer, please share. I am most interested to know what make and model the original furnace and fridge were.

Thanks

[WILDEBILL308]

PVC and ABS are now being replaced by PEX. I had to learn a whole new process this spring.
Bill

[wintersun]

Water supply lines, hot and cold, are not going to be PVC or ABS in any building or RV. Instead a flexible line is used and unfortunately this practice has extended to residential construction with PEX where it is a poor substitute for copper piping. Waste lines outside the living space are always done with ABS pipe where the installation is a permanent one and not easily repaired or replaced.

I have a sprinkler system at my house for which I naturally used PVC. All the exposed pipe has become brittle in less than a year's time. I would not want PV used in a RV for pressure lines.

PVC also loses strength with temperature. A pipe that has a PSI burst strength of 450 PSI at 73 F (temp used for standards) will have a pressure rating of 337 PSI at 100 F.

PCV also expands with temperature and a 100' length can expand 4 inches with 140 degree water inside (or less with outside air temps over 100 F) and with an RV a 20' length could still expand an inch and cause a problem.

With an RV the manufacturers err on the safe side to avoid plumbing problems that could be prohibitively expensive to repair with the very limited access with most RV's.

[beemerphile1]

My experience has been that most manufacturers and professional plumbers use ABS and home handymen use PVC. My guess is cost and availability.

[dougrainer]

Strength

ABS piping has a higher impact strength than PVC, especially at lower temperatures. However, ABS can deform under sun exposure.

Durability

ABS is highly durable with high impact strength. PVC is less durable, as it is designed to be flexible and softer than usual plastics. However, both plastics are resistant to chemical and water degradation.

Doug

[westend]

ABS is more impact resistant and probably has more wall strength but I'm not sure about the latter.

[mobeewan]

May have to do with UV exposure for outside use with the tanks. Could also be that sealers used at tank connections work better with ABS.

White PVC is not good when exposed to sunlight. Grey PVC (more expensive) is for exterior use.

That is something to consider in the overall cost of keeping 2 different construction materials stocked for separate indoor and outdoor use.

[time2roll]

http://drainwastevent.com/

PVC appears to be superior to ABS and is an accepted replacement.
I think the glue might be a bit different so watch the transition.

[n7bsn]

PCV does not handle vibration as well, but I suspect most of it is simply cost.