2012 Changes in International Residential Code from 2006

Users who are viewing this thread

Brother

Member
Messages
69
Reaction score
0
Points
6
Location
UPC
Had buddy of mine show the IRC concerning the questions I had about water heater tp relief valve drainage. Thanks to all who answered my previous posts.

The question I have is about the change they made from the 2006 to the 2012 under P2803.6.1 Requirements for discharge pipe.

#5 stated in 2006 edition that the drain pipe will "Discharge to the floor, to an indirect waste receptor or to the outdoors. Where discharging to the outdoors in areas subject to freezing, discharge piping shall be first piped to an indirect waste receptor through an air gap located in a conditioned area.

#5 in the 2012 edition says the drain pipe will "Discharge to the floor, to the pan serving the water heater or storage tank, to a waste receptor or to the outdoors. "

Does anyone know whey the 'subject to freezing' was removed from the 2012 language? I am not a plumber, just trying to learn here. I assume they believe the air gap requirement in #2 would prevent any real issues.
 

WJcandee

Wise One
Messages
3,181
Reaction score
170
Points
63
Location
New York, NY
The change actually took place in the 2009 code, and continued in the 2012 code.

I can only guess at the reason, but here's what I think: Each enumerated requirement in the subsection must be met in all installations, so they are cumulative. Subsection 2803.6.1 expressly requires, in Paragraph 2, that the tp valve discharge into drainage through an air gap located in the same room as the water heater. So if it is discharged to the outside, it automatically has to have an air gap located in the same (presumably warm) room between the valve and the pipe going outside. The "freezing area" requirement in Paragraph 5 is thus redundant and could be confusing -- do I NOT need an air gap located in a warm area if I am discharging to the outside in areas not subject to freezing? Nope. You do, pursuant to Paragraph 2. The 2003 code did not have a universal air gap requirement, and didn't separately-enumerate each requirement; it was just a single paragraph with multiple sentences. I think that when, in 2006, the subsection was broken down into numbered requirements and the air gap added for all installations in Paragraph 2, they just didn't bother to remove the "freezing area" language that was in the 2003 code, but pulled it in 2009 after realizing that it was redundant and confusing.

The point of this "freezing area" requirement is of course to prevent a clog of ice from blocking the output of the valve and causing an explosion. This could happen if the valve, as is often the case, just dribbles from time to time. If a continuous pipe ran from the valve to the outside, those dribbles could freeze into a clog which might or might not give way quickly enough if the valve tried to open to prevent an explosion. Requiring an indoor air gap is important anyway, because just because the pipe to the outside isn't subject to freezing doesn't mean that it isn't subject to clogging. Insects and other things could cause that outside-discharge pipe to clog, so Paragraph 2 prevents explosion by requiring an air gap on any pipe, including those to the outside, so if the drainage is clogged, all that would be caused is a flood, not an explosion.

In another post on here, we have various videos of water-heaters which turned into rocket ships when the tp valve wasn't working. The ones from Mythbusters are pretty amazing. They really will shoot through a floor or two and out the roof.
 
Last edited:

Brother

Member
Messages
69
Reaction score
0
Points
6
Location
UPC
I was curious as to how do they reconcile the UPC and IRC? The UPC prohibits the tp reife valve from bing discharged into the pan and the IRC allows it.
 

Reach4

Well-Known Member
Messages
38,796
Reaction score
4,412
Points
113
Location
IL
Governments decide which to adopt, if any. Then often they make amendments using the selected code as a starting point, but they publish the local differences.
 

WJcandee

Wise One
Messages
3,181
Reaction score
170
Points
63
Location
New York, NY
The state or local government will decide which code to adopt/adapt. The UPC as a broad sweeping generalization requires a more robust plumbing system than does the IRC. Bigger vents, different fixture counts, etc. Some munipalities try to adopt the IRC as part of a simple adoption of the I-codes, which is easy for them to do. Often, thinking local plumbers will raise hell when they try to do this.

If you are in Tacoma, it follows the UPC, with the exception of a few amendments and a refusal to adopt two chapters. It is all spelled out here, in Chapter 2.06: http://cms.cityoftacoma.org/cityclerk/Files/MunicipalCode/Title02-Buildings.PDF

I am under the impression that dumping the tp valve into the pan could be considered kinda dumb because it almost certainly is going to overflow the pan or exceed the capacity of the pan's drain, so, unless it is just dribbling, it's not much different than dumping it on the floor. That difference in opinion may be one reason for the difference in the codes.

People who support the UPC say that it maximizes safety and proper functioning. People who argue for the IRC say that all the UPC does is oversize things and sell more and more-expensive plumbing. It's the difference between "good" and "good enough". There are some that will argue that "good enough" isn't really good enough. In our very-old house, everything is oversized as compared to today's standards, with copper pipe everywhere. It sure feels nice to take a shower and know that someone can run the washing machine, the dishwasher, toilets, baths and other showers with minimal effect on my shower. I generally don't even know that any of that is happening. That's good. And way better than minimally-acceptable, or "good enough". I appreciate what those plumbers did a long time ago every time I open a tap.
 
Last edited:
Top
Hey, wait a minute.

This is awkward, but...

It looks like you're using an ad blocker. We get it, but (1) terrylove.com can't live without ads, and (2) ad blockers can cause issues with videos and comments. If you'd like to support the site, please allow ads.

If any particular ad is your REASON for blocking ads, please let us know. We might be able to do something about it. Thanks.
I've Disabled AdBlock    No Thanks