Heated and bent PVC

[Gary Mohel]

Is it proper to heat and bend PVC for plumbing vents? Saw this on an inspection. Noted the heating and bending but I did not know if you can properly do this and what source I can refer to if it is not proper. Seems like a lot of unneeded effort when there are couplings available.

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[Jerry Peck]

No photos, but basically the answer is 'No, not allowed.' You are describing "changed in direction" in the piping, which is addressed here:

From the 2006 IRC. (underlining and bold are mine)
- P3005.1 Drainage fittings and connections. Changes in direction in drainage piping shall be made by the appropriate use of sanitary tees, wyes, sweeps, bends or by a combination of these drainage fittings in accordance with Table P3005.1. Change in direction by combination fittings, heel or side inlets or increasers shall be installed in accordance with Table P3005.1 and Sections P3005.1.1 through P3005.1.4. based on the pattern of flow created by the fitting.

[A.D. Miller]

No photos, but basically the answer is 'No, not allowed.' You are describing "changed in direction" in the piping, which is addressed here:

From the 2006 IRC. (underlining and bold are mine)
- P3005.1 Drainage fittings and connections. Changes in direction in drainage piping shall be made by the appropriate use of sanitary tees, wyes, sweeps, bends or by a combination of these drainage fittings in accordance with Table P3005.1. Change in direction by combination fittings, heel or side inlets or increasers shall be installed in accordance with Table P3005.1 and Sections P3005.1.1 through P3005.1.4. based on the pattern of flow created by the fitting.


JP: Agreed. I only ever see this on pool and spa installations. I write it up for the reason you posted plus:

(1) Heating the pipe decreases the pipe's wall thickness thereby lessening the integrity of the piping.
(2) This decreases the designed operating pressure of the piping.
(3) Heating tends to make the piping elipsoid rather than round.
(4) This sort of alteration of a code-approved material would require testing and approval of the AHJ.

[Matt Vozzella]

(4) This sort of alteration of a code-approved material would require testing and approval of the AHJ.

I would think the AHJ wouldn't approve the change - The heating removes any ASTME rating of the piping.

[A.D. Miller]

I would think the AHJ wouldn't approve the change - The heating removes any ASTME rating of the piping.

MV: Excellent point.

[Jerry Peck]

Correct, for plumbing, heating the pipe is not allowed for all the reasons mentioned above.

The pipe is no longer "approved" or "listed and labeled" as that listing as been voided.

I took the easy way out and simply pointed out that any change in direction had to be made with a fitting designed and approved for that purpose - glad that you guys followed up with the additional information.