Mixed ABS & PVC Drain Piping

[Gunnar Alquist]

I tried to look this up in the archive, but did not find a match, so I'm hoping that someone here can help.

Periodically, I will run across a combination of ABS and PVC drain piping under a home, sometimes going back and forth between the two materials. I have been under the impression that mixing the two materials could be done, if the proper cement (greenish-blue) was used.


I was looking for a specific code section (for something else) in my aging copy of Code Check Complete and ran across a mention that ABS and PVC could not be connected together EXCEPT at the building drain or building sewer. I pulled-up my 2016 CPC and could not find it, so I then looked up 316.1.6 in the 2007 CPC, and there it was.


316.1.6 Solvent Cement Plastic Pipe Joints.
Plastic pipe and fittings designed to be joined by solvent cementing shall comply with appropriate IAPMO Installation Standards.
A solvent cement transition joint between ABS and PVC building drain or building sewer shall be made using a listed transition solvent cement.


I have been unable to locate that statement in the 2016 CPC and wondered if anyone else has. I did manage to find something of a similar nature, but it opens a new question. Has anyone seen an "approved listed adapter or transition fitting" or would the special cement work?


705.9.3 Plastic Pipe to Other Materials. Where connecting plastic pipe to other types of plastic or other types of piping material; approved listed adapter or transition fittings and listed for the specific transition intended shall be used.


Or, have I misunderstood the entire point?

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[Jerry Peck]

Periodically, I will run across a combination of ABS and PVC drain piping under a home, sometimes going back and forth between the two materials. I have been under the impression that mixing the two materials could be done, if the proper cement (greenish-blue) was used.

I was looking for a specific code section (for something else) in my aging copy of Code Check Complete and ran across a mention that ABS and PVC could not be connected together EXCEPT at the building drain or building sewer. I pulled-up my 2016 CPC and could not find it, so I then looked up 316.1.6 in the 2007 CPC, and there it was.

316.1.6 Solvent Cement Plastic Pipe Joints.
Plastic pipe and fittings designed to be joined by solvent cementing shall comply with appropriate IAPMO Installation Standards.
A solvent cement transition joint between ABS and PVC building drain or building sewer shall be made using a listed transition solvent cement.

First, that isn't saying what you think it says.

We need to start with the definitions of what is what, in this case, the definitions of "building drain" and "building sewer".

BUILDING DRAIN. The lowest piping that collects the discharge from all other drainage piping inside the house and extends 30 inches (762 mm) in developed length of pipe, beyond the exterior walls and conveys the drainage to the building sewer.

BUILDING SEWER. That part of the drainage system that extends from the end of the building drain and conveys its discharge to a public sewer, private sewer, individual sewage-disposal system or other point of disposal.

That says that "A solvent cement transition joint between ABS and PVC building drain or building sewer" ... in the building drain (see definition) ... "or" ... in the building sewer (see definition) ... not where the two connect ... "shall be made using a listed transition solvent cement". The "or" clarifies that it is not stating where the two connect, but that when the two types are mixed 'in' one part of the system ... "or" ... the other part of the system, that the proper solvent cement shall be used.

I have been unable to locate that statement in the 2016 CPC and wondered if anyone else has. I did manage to find something of a similar nature, but it opens a new question. Has anyone seen an "approved listed adapter or transition fitting" or would the special cement work?

But this is saying what you thought the IAPMO was saying, and it says it clearly (underlining and bold are mine)
IRC
- P3003.13.4 Plastic pipe or tubing to other piping material.
- - Joints between different types of plastic pipe shall be made with an approved adapter fitting or by a solvent-cement joint only where a single joint is made between ABS and PVC pipe at the end of the building drainage pipe and the beginning of the building sewer pipe using a solvent cement complying with ASTM D3138. Joints between plastic pipe and other piping material shall be made with an approved adapter fitting. Joints between plastic pipe and cast-iorn hub pipe shall be made by a caulked joint or a mechanical compression joint.

[Gunnar Alquist]

Jerry,

P3003.13.4 is IRC. Unfortunately, California only enforces the building section of the IRC. We are on the 2016 CPC, which is a modified version of the 2015 UPC. While the definition from the IRC is better, I have to stick with the one in the CPC.

So, now I might be completely lost. First I need to clarify in my own mind the two definitions. Below are application of common examples.

BUILDING DRAIN: In most homes that I inspect, this is a 3" pipe to which all of the drain pipes from the various plumbing fixtures (sinks, showers, tubs, toilets, laundry, etc.) are connected, which then runs 30 inches past the exterior foundation wall of the home toward the street. The portion under the home (foundation crawlspace) might be partially above ground or might be partially buried.

BUILDING SEWER: Connects between the building drain and the city sewer at the street (around here, most folks refer to that as the "sewer lateral"). This is underground and I am not likely to see it.

Essentially correct? If not, then the rest of this is pointless.

705.8 is about "special joints". The code has no definition for what they consider "special" but 705.8.4 refers only to the connection between the building drain and building sewer when ABS and PVC piping is used. Further, (assuming my above reworded definitions are correct) this is buried, outside the building, and I am unlikely to see it unless it's new construction or someone has dug it up.

705.8 Special Joints. Special joints shall comply with Section 705.8.1 through Section 705.8.4.


705.8.4 Transition Joint. A solvent cement transition joint between ABS and PVC building drain and building sewer shall be made using listed transition solvent cement in accordance with ASTM D3138.

Then 705.9 talks about connecting one material of pipe to another. The various sections of the code that I have not included have connections between copper and cast iron, stainless steel and other materials, etc. as well as ABS to PVC.


705.9 Joints Between Various Materials. Joints between various materials shall be installed in accordance with the manufacturer's installation instructions and shall comply with Section 705.9.1 through Section 705.9.4. Mechanical couplings used to join different materials shall be in accordance with ASTM Cl173 for belowground use, ASTM C1460 for aboveground use, or ASTM C1461 for aboveground and belowground use.

Again, assuming I have correctly understood all of the above, 705.9.3 addresses plastic to other plastic as well as other materials.


705.9.3 Plastic Pipe to Other Materials. Where connecting plastic pipe to other types of plastic or other types of piping material; approved listed adapter or transition fittings and listed for the specific transition intended shall be used.



This seems to me to say that you can only use the special cement between one type of plastic building drain to another type of building sewer (i.e. ABS building drain to PVC building sewer outside of the building and buried) and whenever you have any other dissimilar materials, transition fittings or adapters are necessary.

Did I get it essentially right this time?

If so, what are these "transition fittings" and "adapters"? Could a no-hub coupling (specifically for plastic pipe) be used?

My head hurts. I'm going to bed now.

[Darren Miller]

Here's what New Jersey has to say...

[Gunnar Alquist]

Here's what New Jersey has to say...

Darren,

Thank you. That was my interpretation as well. Although I didn't say it as clearly.

I also posted the question on the CREIA message board and got this response from Douglas Hansen (CodeCheck, Electrical Inspection of Existing Dwellings, etc.).

"In the 2019 California Plumbing Code, they nudged it to section 705.9.4. The language they chose seems to make the point that they are talking about one location only where solvent cement is acceptable: "A solvent cement transition joint between ABS and PVC building drain and building sewer shall be made using listed transition solvent cement in accordance with ASTM D3138". Richard's great photo of it on a trap arm would not be an approved application. Typically, the transition of building drain to building sewer has a 2-way cleanout. In our jurisdiction we also require one at the transition to the city-owned piping at the street.


Douglas Hansen"

[John Dirks Jr]

In my 12 years inspecting homes, I've yet to see a leaking joint of PVC to ABS. I'm sure it happens but I've not caught it so far.

[Steve Klassen]

I'm not sure why people want to dissect code for the answers
Were not code inspectors
Try talking to plumbers for straight forward answers
PVC pipe can be used as long as it is schedule 40, and can be joined to ABS as long as the proper glue/solvent is used (which cant be conclusively be determined during a home inspection)
As long as all the pipe is schedule 40, I write up the solvent/glue thing as a limitation to the inspection.
I also have never seen one of these joints leak. (yet)
Lets keep it simple folks

[Gunnar Alquist]

I'm not sure why people want to dissect code for the answers
Were not code inspectors
Try talking to plumbers for straight forward answers
PVC pipe can be used as long as it is schedule 40, and can be joined to ABS as long as the proper glue/solvent is used (which cant be conclusively be determined during a home inspection)
As long as all the pipe is schedule 40, I write up the solvent/glue thing as a limitation to the inspection.
I also have never seen one of these joints leak. (yet)
Lets keep it simple folks

Steve,

I am going to have to disagree with you there. I understand that "we are not code inspectors", but the reality is that the codes are really the only building standard that can be relied upon, and your inspections and reports are still largely based on what is written in the codes. I do not believe that I can just tell a client "Well, I just don't like the way that has been done." I believe that I should know what I am talking about, even if I am not going to quote code in my report. Also, I have found that many plumbers don't know code. So asking them is not necessarily going to give me a correct answer.

For example; can a circuit breaker panel be installed in a clothes closet? Can more than one neutral conductor be connected at a terminal? These two things (there are others) were improperly enforced for years (at least around here) primarily because the code, as written, was not adequately understood.

And, no. According to the plumbing codes, PVC and ABS cannot be glued together, except at one place. I agree with you that I have not seen an ABS-PVC glued joint leak, but for that matter, I have not seen a fire start due to a circuit breaker panel installed in a clothes closet either.

[Jerry Peck]

Try talking to plumbers for straight forward answers
.
.
Lets keep it simple folks

Keeping it simple here.

Do you think that all plumber always do things according to the code all the time, or is it more likely that they do things 'the way they were taught/saw others doing things as they were learning the trade?

Well, that and 'this is what I happen to have on the truck, and it will work' ... which is something they likely also saw during their 'learning to be a plumber' period.

If we really want to keep it simple, then this is the way to do it:

Arrive at the inspection; look around for fire trucks and rescue units; look at the house ... if the house is still standing and there are no fire trucks or rescue units outside ... how bad can the house be?

The home inspection is complete.

Keeping it simple.

[Jerry Peck]

For example; can ... ? Can ... ?

(Cringe ... cringe ... shiver me timbers ... )

We see is, and photos of it, being done all the time, so, 'can it be done?' ... Yeppers ... is it allowed to be done? ... Nope.

Just pointing out that wording matters, and the use of 'can this been done' when I am asked a question about a photo showing that it WAS done, brings out the answer of 'Yes it can, we're looking at it, but if you are asking if it is allowed to be done, no, it is not.'

And I use 'allowed' instead of 'permitted', as in 'that is permitted to be done' because we have no idea if it was permitted or not, but the code which should have been followed "allows" (or "does not allow") it to be done.

[Gunnar Alquist]

Oy! Edited to get Jerry off of my back.



Steve,

I am going to have to disagree with you there. I understand that "we are not code inspectors", but the reality is that the codes are really the only building standard that can be relied upon, and your inspections and reports are still largely based on what is written in the codes. I am not willing to just tell a client "Well, I just don't like the way that has been done." I believe that I should know what I am talking about, even if I am not going to quote code in my report. Also, I have found that many plumbers don't know code. So asking them is not necessarily going to give me a correct answer.

For example; is a circuit breaker panel allowed to be installed in a clothes closet? Is more than one neutral conductor allowed to be connected at a terminal? These two things (there are others) were improperly enforced for years (at least around here) primarily because the code, as written, was not adequately understood.

And, no. According to the plumbing codes, PVC and ABS are not allowed to be glued together, except at one place. I agree with you that I have not seen an ABS-PVC glued joint leak, but for that matter, I have not seen a fire start due to a circuit breaker panel installed in a clothes closet either.[/QUOTE]