Ask the Home Inspector: Can I Join ABS to PVC?
There are ii commonly used plastics for drain, waste material, and vent pipes inside of homes: ABS (black) and PVC (white, mostly). These two plastics are near all that is ever used in new residential structure here in Minnesota, and I doubtable for the residual of the land as well. For most systems, a plumber will use one material or the other, but not both. This makes all of the connections elementary; the plumber uses a solvent cement (aka glue) made simply for that material, things stick together, and everyone is happy…
Until and then the "handy" homeowner comes along and messes it upwards.
For the most part, ABS and PVC are not supposed to be glued together. We'll turn to the Minnesota State Plumbing Code for some background on this topic. (The Minnesota Code is used for reference because that's where I alive. Always check your local codes.)
ABS to PVC: What does the MN plumbing code say?
If nosotros read chapter 7 of the MN state plumbing code, we tin observe a agglomeration of info on drains. Section705.1.2: ABS Solvent Cement Joints (for ABS) says the following, among other stuff:
Where surfaces to be joined are cleaned and costless of clay, moisture, oil, and other foreign material, solvent cement in accord with ASTM D 2235 shall be applied to all joint surfaces.
And then according to this, you can gum ABS using something that meets ASTM D 2235 (the standard for solvent cement for ABS).
Section705.7.ii: Solvent Cement Joints (for PVC) says the following, amid other stuff:
Where surfaces to be joined are cleaned and gratuitous of dirt, wet, oil, and other strange cloth, apply primer purple in color in accordance with ASMT F 656. – and –Solvent cements in accordance with ASTM D 2564 shall be applied to all joint surfaces.
Then as long equally y'all employ the right purple primer, y'all tin can also gum PVC. Y'all also need to apply a mucilage that meets ASTM D 2564, the standard for solvent cement for PVC, of course.
So how tin these two materials be continued together? Nosotros need to turn to department705.11.3:PlasticPipe to Other Materials:
Where connecting plastic pipe to other types of plastic or other types of piping fabric; approved listed adapter or transition fittings and listed for the specific transition intended shall be used.
That means that if ABS and PVC are connected together, some type of adapter or fitting needs to be used. That's it. That's all that'southward allowed. The paradigm below shows one such adapter on the correct side. This has a stainless steel band going through the centre for rigidity. The image on the left shows a coupling that lacks a metal ring in the middle and likewise lacks UPC blessing.
What about ABS to PVC Cement?
If you stop past any home improvement store, you'll exist able to find a green cement that will connect ABS to PVC. Information technology might even have an IAPMO blessing stamp on it (UPC), and so what could the problem be? I mean, if it's canonical, it'south approved, right?
The problem is in the standard. If yous look up the technical specifications for the product, you'll find that it meets ASTM Standard D 3138. You'll notice the following information on the ASTM website.
one.2 These cements are intended for use in cementing transition joints between ABS and PVC materials in not-pressure level applications just (25 psi (170 kPa) or less). Note 1 This specification was developed to provide a ways for joining an ABS non-pressure level piping organisation using a solvent-cemented transition joint, for instance, joining ABS building drain to a PVC sewer arrangement.The intention was not to create a specification for an all purpose ABS-PVC solvent cement that would exist used for mixing of ABS and PVC pipage materials nor to specify a cement that could by and large exist used for either material. Specific cements for ABS or PVC components should exist used (encounter ).
That spells it out pretty clearly, yeah? ABS to PVC cement is only meant to connect an ABS arrangement to a PVC organisation. An example of this would be an ABS drain arrangement inside of a domicile connecting to a PVC drain system only outside the building, or vice-versa. That'due south the merely place that this cement is supposed to be used.
What if ABS and PVC accept already been cemented together?
To this I say 'meh'- it is no big deal if this is done. It's technically non right, but that'south all. I accept yet to find a unmarried failure at this connection point. I've talked to a handful of experienced plumbers most this, and not one of them take seen this connection fail either. I typically bespeak it out as an improper installation, just I leave information technology at that. I don't tell people to rip information technology autonomously and put it dorsum together. Why would I?
Simply for fun, I did a trivial experimenting at habitation to show how some of these different types of cement hold up. I started by cementing a bunch of materials together with a agglomeration of different types of cement. I waited 24 hours, then cut each one roughly in half, down the centre.
Next, I cut each section in half lengthwise and put the coupling in a vice to get the materials to split up.
I got well-nigh of the connections to separate, simply not all of them.
The easiest section to carve up was the PVC to PVC without purple primer. Next was the ABS to PVC without royal primer. The ABS to PVC connections with purple primer were as stiff equally the PVC to PVC connections with imperial primer, if not stronger. Information technology really seemed to pull the surface of the ABS right off of the pipe. The only connection that refused to come autonomously was the ABS to ABS; the plastic would probably rip autonomously before that connection would fail.
Over again, an ABS to PVC glued connection isn't technically correct, but this connexion is highly unlikely to fail. I remember failure is close to incommunicable; if I hadn't used a vice, at that place's no way I could have separated the two. There's no need to lose sleep over connections like this.
About the writer
Reuben Saltzman is a second-generation home inspector and the possessor and president of Structure Tech Home Inspections in Minnesota.
Source: https://www.familyhandyman.com/article/can-i-join-abs-to-pvc/
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