Approved water heater discharge material

Does anyone have a list of the Iapmo approved list for the material to be used for the pressure relief valve extension . I found one with pex style pipe installed at the PRV and the contractor says its ok. I did find where Pex style is not allowed within 18 inches of the water heater. 2009- 508.5 Iapmo

eh hum

18" is for service pipe. Only hard pipe is allowed for TPRV discharge in Illinois, don’t know about California.

Thanks Mike , I’ve seen the IRC requirements but here we dont use IRC for plumbing or mechanical. California uses Iapmo UPC uniform pluming code.

Given in a TPR valve pex is not exposed to hot water 100% of time, I can’t see a reason it would wrong if Pex IS approved for continuous hot water exposure.

Ah, here we go:

Although, you possibly make an argument PEX is considered a “listed relief valve drain tube” given Pex is a tube approved for hot water use. :wink:

Thanks Ian, I appreciate it.

I dont know how the fitting would handle a surge in pressure

Also the pipe is reduced from the original size of the valve

How much pressure is there on a open ended pipe?