PVC tpr drain

[Chris Stichter]

I know this has been discussed before, however, I'm being challenged by the plumber (via the seller). The question: Is there pvc rated for tpr drain lines? The plumber says its fine. It was my contention that it was not. I told the seller that if the plumber says otherwise to please provide me with some documentation to update my records....Thanks for your help!

Chris

[Gunnar Alquist]

I know this has been discussed before, however, I'm being challenged by the plumber (via the seller). The question: Is there pvc rated for tpr drain lines? The plumber says its fine. It was my contention that it was not. I told the seller that if the plumber says otherwise to please provide me with some documentation to update my records....Thanks for your help!

Chris,

There is a plastic drain pipe that is rated and it is specifically labeled. Otherwise, the IRC (and, I believe the water heater manufacturer) does specify a metal TPR drain. If the plumber can provide documentation, please post it for us as well.

[Jerry Peck]

Is there pvc rated for tpr drain lines?


There is a plastic drain pipe that is rated and it is specifically labeled.

CPVC is rated for that use.

As Gunnar said, there is (someone posted a photo of it) a PVC or PVC looking plastic T&P discharge line made and rated for that use, with the standard it was tested to stamped on it and the product approval stamped on it.

Either that information was stamped on it, or it was just marked as 'Suitable for use as temperature and pressure relief valve discharge line.' - but without the other markings and we questioned its approval for that use.

I don't remember whether it had the approvals on it or not.

Anyone remember those posts and that photo?

As Gunnar said, have the plumber "prove it", because unless he can "prove it", the answer is no, it is not allowed, which is what you stated.

From the 2006 IRC.
- P2803.6.1 Requirements for discharge pipe. The discharge piping serving a pressure-relief valve, temperature-relief valve or combination valve shall:
- - 13. Be constructed of those materials listed in Section P2904.5 or materials tested, rated and approved for such use in accordance with ASME A112.4.1.

TABLE P2904.5
WATER DISTRIBUTION PIPE
MATERIAL ------------------------------------------------ STANDARD
Brass pipe ------------------------------------------------ ASTM B 43
Chlorinated polyvinyl chloride (CPVC) plastic pipe and tubing - ASTM D 2846; ASTM F 441; ASTM F 442; CSA B137.6
Copper or copper-alloy pipe -------------------------------- ASTM B 42; ASTM B 302
Copper or copper-alloy tubing (Type K, WK, L, WL, M or WM) -- ASTM B 75; ASTM B 88; ASTM B 251; ASTM B 447
Cross-linked polyethylene (PEX) plastic tubing ---------------- ASTM F 877; CSA B137.5
Cross-linked polyethylene/aluminum/cross-linked polyethylene (PEX-AL-PEX) pipe - ASTM F 1281; CSACAN/CSA-B137.10
Cross-linked polyethylene/aluminum/high-density polyethylene (PEX-AL-HDPE) - ASTM F 1986
Galvanized steel pipe ---------------------------------------- ASTM A 53
Polybutylene (PB) plastic pipe and tubing --------------------- ASTM D 3309; CSA CAN3-B137.8
Polyethylene/aluminum/polyethylene (PE-AL-PE) composite pipe - ASTM F 1282
Polypropylene (PP) plastic pipe or tubing ----------------------- ASTM F 2389; CSA B137.11
Stainless steel (Type 304/304L) pipe -------------------------- ASTM A 312; ASTM A 778
Stainless steel (Type 316/316L) pipe -------------------------- ASTM A 312; ASTM A 778

As you can see, PVC is not in Table 2904.5 and is thus not allowed, unless it is "materials tested, rated and approved for such use in accordance with ASME A112.4.1." - thus if it does not state that it is ASME A112.4.1 approved, it is not allowed to be used for that use.

[Billy Stephens]

Anyone remember those posts and that photo?

.
.
Thread title: pvc pipe from pressure relief. Author: Matt Fellman, last posted to 2-25-08.
( sorry could not get link to come up. )

[James Bohac]

I often see a plastic drain line for the water heater in manufactured housing. It appears to be a form of PEX material.

[Jerry Peck]

Billy,

Thank you, that is the one, and, if I remember, the conclusion was just as I posted above:

As you can see, PVC is not in Table 2904.5 and is thus not allowed, unless it is "materials tested, rated and approved for such use in accordance with ASME A112.4.1." - thus if it does not state that it is ASME A112.4.1 approved, it is not allowed to be used for that use.

Unless it is stamped on it that it is approved per ASME A112.4.1, and if it is PVC and not CPVC, then it cannot be (er ... okay, it *can be* - we saw it - but ... ) ... then it *IS NOT ALLOWED TO BE* used for that use.

[Jerry Peck]

It appears to be a form of PEX material.

PEX is listed in the table I posted above, thus that would be acceptable for use as a T&P relief valve discharge line.

[Tim Kallmer]

I understand PEX and CPVC being listed in the table above, but what about the temperature ratings of these? I believe these are rated up to 180-degF. Steam discharging from the TPR could be 212-degF. Any problem there? Thanks.

[Scott Patterson]

I understand PEX and CPVC being listed in the table above, but what about the temperature ratings of these? I believe these are rated up to 180-degF. Steam discharging from the TPR could be 212-degF. Any problem there? Thanks.

No problems until it melts! :D

I think most PEX is rated in the high 200 deg F range.

[Joshua Hardesty]

Something else that comes into play, is that while these plastic pipes are rated at a specific temperature and pressure range, the T&P discharge is open, so there's not really any pressure on it. Structural integrity isn't *quite* as important at higher temperatures if there's no pressure on the line.