Approved water heater discharge material

[erichards1 (Eric L. Richards)]

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

[mlarson (Michael Larson, WI Lic. # 1672-106)]

eh hum

Tpr Discharge line is PEX

[ccurrins (Christopher Currins, CMI)]

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

[erichards1 (Eric L. Richards)]

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.

[imayer (Ian Mayer, CMI)]

http://www.iapmo.org/2010%20California%20Plumbing%20Code/Chapter%2006.pdf

PEX tubing shall meet or exceed the requirements of ASTM F876-08 or an equivalent or more stringent standard when used in continuously recirculat-
ing hot water systems and the PEX tubing is exposed to the hot water 100% of the time.

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:

608.5
Relief valves located inside a building shall be provided
with a drain, not smaller than the relief valve outlet, of galva-
nized steel, hard-drawn copper piping and fittings, CPVC or
listed relief valve drain tube with fittings that will not reduce
**the internal bore of the pipe or tubing **(straight lengths as op-
posed to coils) and shall extend from the valve to the outside of
the building, with the end of the pipe not more than two (2)
feet (610 mm) nor less than six (6) inches (152 mm) above
ground or the flood level of the area receiving the discharge
and pointing downward. Such drains shall be permitted to ter-
minate at other approved locations. Relief valve drains shall
not terminate in a building’s crawl space. No part of such drain
pipe shall be trapped or subject to freezing. The terminal end of
the drain pipe shall not be threaded.

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.

[erichards1 (Eric L. Richards)]

@imayer

http://www.iapmo.org/2010%20California%20Plumbing%20Code/Chapter%2006.pdf
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.

Thanks Ian, I appreciate it.

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

[erichards1 (Eric L. Richards)]

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

[mlarson (Michael Larson, WI Lic. # 1672-106)]

@erichards1

Thanks Ian, I appreciate it.

I don’t know how the fitting would handle a surge in pressure

How much pressure is there on a open ended pipe?