Below is a snippit of a debate I had with the ICC about this conflicting code. They agree that it is poorly worded.
I believe the intent of the code is this and this is what I require as an AHJ in my municipality: 1) To allow the TPRV discharge piping to extend from a water heater in a garage or crawl space directly to the outdoors to a conspicuous area. 2) To allow a garage water heater to discharge to the pan, to the garage floor, or to a waste receptor. 3) Because the discharge piping would not be fully visible, attic or interior units cannot go directly outdoors but must discharge to a waste receptor and the pan is the most logical place.
I DO see the contradiction but I can’t do anything about it. It is the code as developed by the consensus process. I’m not here to defend the code in what it says but only to try and interpret the code to best of my abilities. And I understand your thoughts about an air gap in a crawl space and certainly, as an ex-master plumber, I understand “laughable” code requirements/building official demands. But, the code says what it says and it’s my task to interpret the code as it is written.
I hope you understand that anyone can make a proposal to change the code. If you feel strongly that the code is broken, then you should probably redirect your energies towards completing a code change proposal form and submit a code change proposal for the upcoming code change cycle for the International Residential Code. I can’t write it for you but I help you with getting it completed.
Fred Grable, P.E.
Chicago District Office
International Code Council
From: Joe Funderburk [mailto:email@example.com]
Sent: Monday, April 02, 2012 5:06 PM
To: Fred Grable
Subject: RE: 12 IRC P2803.6.1 (FG)
Thank you for your time and the explanation.
If you will entertain me for one more minute to make my point perfectly clear, please ask yourself why the code and the commentary include the outdoors in the list of acceptable options if the drain must go to a waste receptor (air gap) first? A waste receptor is clearly one of the acceptable options. And then the code says another option is “OR the outdoors”. Don’t you see the apparent contradiction? By your interpretation that ALL discharge from the drain must go to an air gap first, the outdoors is really not an option at all. Yet the outdoors is included in the list of options and it is clearly an option as indicated by use of the word “OR”.
“Water discharged from the T&P valve must be directed to one of four locations: (1) the floor below the water heater; (2) the water heater or storage tank pan, if present; (3) a waste receptor, such as a floor drain; OR (4) the outdoors.”
And yet if the outdoors is an option, then the code contradicts that by stating that all discharge must: “2**. Discharge through an air gap located in the same room as the water heater.” **
I’m scratching my head trying to make sense of it. To me it is very clear that the code contradicts itself when it states in list item 2 that the drain must discharge to an air gap and then states in list item 5 that it is permitted to discharge to an air gap OR the outdoors.
By the way, I do disagree with the logic of running a WH in a crawl space into an air gap in the crawl space. As one who has been in well over a thousand crawl spaces, I can testify to the likelihood of the air gap becoming contaminated/clogged by debris from falling insulation, etc. Also, in 8 years of owning a home inspection company inspecting well over a thousand crawl spaces in many municipalities, large and small in NC and SC, I can say I have NEVER seen a WH in a crawl space discharge to an air gap in the crawl space. If I were to require that as a BO, I’d be laughed out of town by the plumbers you say would be inconvenienced by having to go outside the crawl to inspect the discharge pipe.
Building Official / Town of Clover
114 Bethel St., Clover, SC 29710