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New Construction Plumbing: White PVC vs The Black Stuff

Posted by fmfguy (My Page) on
Fri, Mar 2, 07 at 10:27

OK,

I've always assumed that white pvc pipes used for drains are the only way to go and never even saw the black pipes. Recently, however, I toured a house that the framer we're using built that is a medium range house (not high end) and the plumber there was using the black pipes (don't know the name) then I toured another house the framer was building and a different plumber was using the black stuff as well. This house is going to list on the market for $2.29 Million. A plumber I know told me the black pipes are inferior and used by plumbers to save money. Is this true? What are the differences? I'm confused because even the high end builder was using them. Are they that much cheaper? I can't find out anything about it online. Thanks!


Follow-Up Postings:

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RE: New Construction Plumbing: White PVC vs The Black Stuff

The white pipe is PVC (Poly-vinyl Chloride)
The black pipe is ABS(Acylonitrile-Butadiene-Styrene).

Both PVC & ABS schedule 40 pipe is approved under both the International Residential Code and the Uniform Plumbing Code for DWV (Drain, waste & Vent) applications inside a structure above grade, inside a structure below grade and for direct burial outside a structure. (Note-only schedule 40 is approved for DWV application)

Some local codes will require PVC only or ABS only. (check your local AHJ)

While both materials will provide nearly identical service life ABS is slightly easier to install because it can be glued in one step by the application of the appropriate ASTM rated ABS glue. PVC joints are a two step process requiring the application of an ASTM rated PVC solvent/primer before applying the ASTM rated PVC Glue.

The solvent primer for PVC is made in both a clear liquid and a purple dye type. While both primers are the same most local codes require the use of the purple dye type in new construction so an inspector can be visually assured that the primer was used prior to gluing the joint.

There are some glues on the market that are said to be interchangable between PVC & ABS (Read the labels on the can carefully to insure the glue is rated for the type of pipe you are using.)

Most local codes will restrict you to using a glue or glue & primer made specifically for the type of pipe you are using.

Code prohibits directly gluing PVC to ABS. Some local codes will permit a maximum of one PVC to ABS joint per structure when making a transition of materials but once you have made the transition from one to the other you must continue to finish the job with the new material. Under no circumstances may PVC and ABS pipe and fittings be co-mingled in the system.


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RE: New Construction Plumbing: White PVC vs The Black Stuff

Wow. Thanks lazypup. You're definitely not lazy. Very thorough.

So am I wrong to assume that ABS is cheaper (price wise) ?


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RE: New Construction Plumbing: White PVC vs The Black Stuff

When we compare the basic FOB price of the two types at the factory door they are very cost closely competitive however there can be a slightly noticable price difference at the consumer level. Generally the price difference at the consumer level is influenced more by the physical distance, ergo the freight cost, from the point of manufacture to the point of use. This would then also be influenced by which material is preferred in any specific region. Obviously your supplier would buy the preferred material in larger quantities therefore getting a better wholesale price as well as a better freight rate but in the final analisys if you consider the cost of either material in reference to the total cost of the plumbing in your job you will find that the actual pipe price is a very small percentage of the overall cost. In fact,when considering PVC or ABS for your DWV system it is doubtful if one type of pipe over the other will effect your bottom line price by more than one or two percent


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RE: New Construction Plumbing: White PVC vs The Black Stuff

ABS is more susceptible to damage from exposure to petroleum oils than is PVC. In residential settings, this should not be a problem. But it is one of the differences in the two materials. In NC, the State amendments to the plumbing code absolutely prohibits the direct joining of dissimilar plumbing materials using solvent cements. A Fernco coupling is acceptable.


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RE: New Construction Plumbing: White PVC vs The Black Stuff

Although ABS has been said to be more prone to damage from petroleaum such is not the case. In fact, ABS pipe was originally created for use in the oil industry and it was first used for DWV purpose in phoenix,Az by a petro-chemical engineer who got the pipe from the oil company he worked for.


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RE: New Construction Plumbing: White PVC vs The Black Stuff

Here in Ontario, all DWV piping above the concrete basement floor is exclusively ABS. The four inch piping that is installed below the concrete basement floor is white or green PVC for both the sani and the storm lines. It pokes up through the finished concrete floor and an ABS cleanout is installed right at that point using a transition cement designed to join the two types of plastic. P"ain and simple........it works.

Of course, copper and cast iron are still permitted.


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RE: New Construction Plumbing: White PVC vs The Black Stuff

Here in Manitoba, all DWV is ABS. I didn't see what the contractor ran from the septic tank to the crawlspace, but everything I can see is ABS.


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RE: New Construction Plumbing: White PVC vs The Black Stuff

"...using a transition cement designed to join the two types of plastic.

While the manufacturers claim to have cements for this purpose, none have the correct listing for use in the US by ASTM.
Joining of ABS to PVC is prohibited for this reason.
Good luck with long term reliability.
The last time I looked into the problem the solvents for ABS could cause cracking of PVC under stress long term.
Maybe they changed solvents, but since the ASTM listing has not changed the material remains unallowed in the US.


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RE: New Construction Plumbing: White PVC vs The Black Stuff

ABS is prone to fatigue as a result of direct exposure to sunlight. Some Codes require that all exposed ABS must be painted with latex housepaint for UV protection.


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RE: New Construction Plumbing: White PVC vs The Black Stuff

The coefficients of thermal expansion of ABS and PVC differ enough to be significant in some instances. I rarely see a mixture of those materials on a job. I often see where plumbing installations have not accounted for thermal expansion. The results range from annoying noises to failure.


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RE: New Construction Plumbing: White PVC vs The Black Stuff

Your US code says what it says and I don't dispute that. However, there are millions of such ABS to PVC joints (as I described in my post above) in homes all across this province that date back at least thirty years. I have four such transitional connections in my own home and I built it back in 1989.

Failures as described by you guys are unheard of. If there was a problem, it would have showed up long ago and our code would have changed as a result. As such, I'd say that long-term reliability has been proven and in no need of any luck.

As for ABS and sunlight, I can't think of a single place inside my home where ABS is ever exposed to direct sunlight.


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RE: New Construction Plumbing: White PVC vs The Black Stuff

Thanks for all of the information. I asked this question initially because a relative of mine (plumbing apprentice of sorts) told me that ABS was of inferior quality and morever that it was very loud when water was traveling through it as opposed to PVC which muffled the sound much more effectively. Any truth to this?


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RE: New Construction Plumbing: White PVC vs The Black Stuff

"As for ABS and sunlight, I can't think of a single place inside my home where ABS is ever exposed to direct sunlight."

While this statement may or may not be true forCastoff's structure, it must be remembered that the Vents do pass through the roof where they remain in full direct exposure to sunlight. It is also common for DWV piping in a basement to receive direct sunlight exposure through a window and in some rare instances the local codes permit DWV stacks to be on the exterior of the bldg.

While most homeowners only think in terms of their respective structure it must be remembered that the codes are written to meet the needs of all structures under many varying conditions.


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RE: New Construction Plumbing: White PVC vs The Black Stuff

Ack......where was my head at when I made that comment?

Of course the stacks are totally exposed. Now I have to eat my words and then amend them.

There are millions of homes all across Ontario that have ABS pipe sticking a couple of feet above the roof lines, including my own home. Surprisingly, in spite of the claims in this thread, those stacks don't get replaced due to deterioration. And there are plenty of industrial and commercial buildings that are plumbed with ABS too, including exposed stacks on flat roofs.

From this guy's perepective, I think your code is vastly out of tune with the realities of ABS. How is it possible for plumbers in Ontario and other provinces to use ABS successfully for more than thirty-years without the sort of problems being touted in this thread?

Here is a link that might be useful: ABS facts


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RE: New Construction Plumbing: White PVC vs The Black Stuff

If you will re-read my post i stated that either PVC or ABS are completely suitable. I merely pointed out that there are some concerns about continued UV exposure to ABS which prompts some local codes to require it to be painted with latex paint.

Personally I would not hesitate to use either product.

On the other hand, although your ABS vent stacks are functioning fine and probably do not need any attention, i can testify first hand that they become very brittle from UV exposure and can easily be damaged by any mechanical stress .


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RE: New Construction Plumbing: White PVC vs The Black Stuff

New concerns here in California ~ new construction ~ stacks to be painted. Some may not due to their influence with building officials.

As far as I understand White PVC will become damaged as will ABS but I have not come across a ABS stack that has broken as much as a PVC stack has ~ on the roof top. ABS is more versatile and widely used here in California. I see PVC used more so as a statement ~ higher end homes ~ but they both get covered in the walls and they both function. PVC take more time to install which = less profit = less project. Time is money 120 joints in a home and I have to glue each joint twice and carry two cans of glue ( ok primer and glue) as opposed to one type of glue. Oh and what about the different sizes of pipe ~ yep different glue.

Plastic is plastic ~ running water makes the same noise regardless if it is PVC or ABS ~ the only way to stop or dampen this as I was told was to replace that plastic section with steel ~ such as running down a dining room wall or a living room wall where you will be watching TV. But in truth ~ you will never be able to eliminate the sound of running water in a wall ~ through a pipe but possible you will be able to minimize it.

I would hope before you run out and start painting you stacks of your house (vent pipes) to make sure the paint will not excel the deterioration of your pipe ~ find a paint that is friendly to your pipes before you paint..

Just my two cents I am throwing into the bowl to swish around..


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RE: New Construction Plumbing: White PVC vs The Black Stuff

As a baby boomer who grew up in rural America I can remember a time when people were not only not offended, they were actually proud of the sound of water rushing through a pipe in the dining room wall, it announced to all your guests that you really did have indoor plumbing, LOL.

Now in regards to why some local codes require ABS instead of PVC there is one consideration that totally eludes not only homeowners but most practicing plumbers. The plumbing codes specifically state that all plastic DWV piping within the structure must be constructed with schedule 40 pipe. Understanding that ABS is only approved for DWV applications, it then stands that the ABS pipe is only made in schedule 40 however:

PVC pipe is used for both DWV and pressure pipe applications therefore it is made in sched.20, sched.40, sched.80, sched. 120 and sched.200 as well as in SDR-20 and SDR-35. With some rare exceptions it is easy to insure that the DWV system is initially constructed with sched.40 PVC because the installation with undergo and onsight inspection during the construction. On the other hand, after the initial construction when an untrained homeowner or novice DIY-er is confronted with maintenance on the system they often take the attitude that "plastic is plastic" and "PVC is PVC" giving little regard to the actual weight of the pipe, but rather they just use whatever they may have at hand or whichever is the cheapest or most convenient to reach at the hardware store. In order to insure that people do not use the wrong pipe some local codes have adopted a policy of only approving the ABS.


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RE: New Construction Plumbing: White PVC vs The Black Stuff

I'm not a big tree hugger type but, PVC is aid to be very bad for the enviroment and is a contaminant in the recycling chain.
Here in Northern California we use ABS, you cannot even find PVC DWV at the supply house.
I understand you can test a PVC system with air but not ABS.
ABS is very strong, try beating a hole in it with a hammer some time, PVC will shatter.
On medium to high end homes we always use cast iron for the second floor drains and down the wall for noise.


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RE: New Construction Plumbing: White PVC vs The Black Stuff

I have been a contractor in South Dakota for 11 years, that does not make me an expert but I can say for certain that pvc degrages in direct sunlight by getting very brittle. And it does this quickly, with in like a year. As for the abs I can't say much as it is not allowed to be used. Just my two cents.


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