# PVC vs. ABS toilet floor flanges



## RippySkippy (Feb 9, 2007)

From what I've observed, the use of PVC or ABS seems to be primarily regional. Around here...houses built into the mid 80's had a mix of ABS...but most were PVC. Now PVC is the norm. You almost have to go out of your way to find ABS and the fitting selection not as extensive as for PVC.

For the flanges in particular, the types we have readily available are PVC, PVC with brass ring, stamped steel, or cast iron. The only one I'd even consider is PVC with brass, but there's no clear advantage so for me it's PVC. I've not had a PVC flange fail in residential housing, assuming everything was installed correctly.


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## RippySkippy (Feb 9, 2007)

Nestor_Kelebay said:


> I understand that PVC is intended to be used in commercial applications. Why is that, and why isn't ABS approved for commercial applications?


From the Charlotte Pipe company site..the comparisons between ABS and PVC are very similar except for one...fire. That would be my guess as to why it's not used in commercial applications.


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## majakdragon (Sep 16, 2006)

I agree with the "supply" situation being small with ABS. Unless you have a plumbing supply store in your area, you will not find a large selection of ABS at Lowes or HD, where most DIYer's shop.


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## Nestor_Kelebay (Jun 17, 2008)

So, from a physical properties standpoint, like strength, hardness, toughness, chemical resistance and the like, there's no clear advantage in either plastic over the other.

ABS is more flammable and so that's the only reason it's not approved for commercial applications. Have I got that right?

It seems to me that neither plastic is very flammable. They'd both melt into a blob and turn into black char.

But, maybe ABS releases more harmful fumes when it melts into a black charred blob than PVC.


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## RippySkippy (Feb 9, 2007)

Nestor_Kelebay said:


> So, from a physical properties standpoint, like strength, hardness, toughness, chemical resistance and the like, there's no clear advantage in either plastic over the other.


I would agree. In addition, the have similar restrictions.



Nestor_Kelebay said:


> ABS is more flammable and so that's the only reason it's not approved for commercial applications. Have I got that right?


seems so...the MFG page says PVC is self-extinguishing so I would assume ABS isn't.



Nestor_Kelebay said:


> It seems to me that neither plastic is very flammable. They'd both melt into a blob and turn into black char.


Yup...



Nestor_Kelebay said:


> But, maybe ABS releases more harmful fumes when it melts into a black charred blob than PVC.


Could be. So given the facts...why would one choose ABS? I'm not sure why they have 2 products with such close characteristics. There must be subtle differences...but they are not listed.

I guess for me, since there are no clear advantages to use ABS...I'll stick with PVC.


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## jogr (Jul 24, 2007)

ABS isn't legal here but PVC is (maybe because of the burn difference?). I guess the best answer I have is to match the existing plumbing if your code permits either one.


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