TPR has PEX2 for discharge piping

New home construction - PEX 2 used for TPR discharge piping at tank. On the exterior it was plumbed with copper. From what I understand the discharge piping can only be galvanized steel, hard drawn copper or cpvc.
First time I have seen this setup. Any comments would be appreciated.
Also foam was used around flue. I dont think foam can be used for this purpose. Any comments would be appreciated.





I don't have the IRC handy...but my understanding is the discharge pipe can be the following:
  • Hard Drawn Copper, CPVC, polybutylene or steel…

polybutylene…imagine that…well thats because the pipe would be fine…but the fitting would blow to heck…thehehe

The requirements for pipe material are at IRC P2803.6.1: “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.”

A screen shot of the table is attached, and PEX is on the list. (Think about it, if PEX is suitable for distribution of hot water, why not as a discharge for it? About the fittings, don’t they withstand all the pressure in the system under normal conditions and wouldn’t you think there is a pretty high safety factor built in? I don’t know the limitations on the fittings, but the table seems to be clear.)

P2904-05.pdf (157 KB)

PEX is acceptable here.

I personally think the TPR discharge piping should be rated for the same temperature and pressure that pops the valve. Most water heaters have valves that open at 150 psi, or 212 degrees. Is pex or cpvc rated that high?

If the drain pipe were closed, I would agree with you. But with an open pipe, it won’t have to take the pressure or the temperature for any extended period of time, usually something on the order of seconds. If you look at pressure and temperature ratings, the rating tests usually take place over minutes or hours.

Piping is rated at 1000 psi at 180 degrees. I got that off the pex markings on the piping.

Where did you get your copy of the IRC in pdf form?

what do you guys think about what appears to be can insulation around the vent in picture 3. Is this acceptable. Is this fire stop? (see first post)

There is some foam that is rated for high temperatures, but could you verify that the foam used is the high-rated foam? Paid $54.50 to download the PDF file of the entire 2006 IRC.

Nice Joe