# Would you approve this T & P installation?



## mtlogcabin (Jun 28, 2013)

We have the plumbers discharge the T&P and the pan drain to the garage because there is less chance of the T&P freezing if a small leak happens during the winter months. Found this combination, plumber stated the state allows this configuration because of the freezing issue. This a separate room directly accessed from the garage and includes the crawlspace access so the potential for someone getting hurt if the T&P discharges is pretty nil. We use the 2009 UPC for our plumbing code.


----------



## ICE (Jun 28, 2013)

There's at least two 90s and I wonder if the water will pile up and backup.

So no I wouldn't want to approve that.


----------



## globe trekker (Jun 28, 2013)

I don't believe that the regular pvc is allowed on the T & P drain line, because it is not rated for those

high of temperatures. See Section P2803.6.1, No: 13, and Table P2904.5 in the 2006 Edition of the

IRC.

.


----------



## JMORRISON (Jun 28, 2013)

Only if the T & P were piped separate from the pan, as pictured it will flood the pan.


----------



## Gregg Harris (Jun 28, 2013)

globe trekker said:
			
		

> I don't believe that the regular pvc is allowed on the T & P drain line, because it is not rated for thosehigh of temperatures. See Section P2803.6.1, No: 13, and Table P2904.5 in the 2006 Edition of the
> 
> IRC.
> 
> .


You would be correct it would need to be CPVC to meet temperature


----------



## mtlogcabin (Jun 28, 2013)

Missed the fact it is not CPVC. For a small leak I think it will work as is, but if the T&P discharges due to high pressure I agree it will allow water and steam to blow back into the pan. The best way is to separate them.


----------



## Uncle Bob (Jun 28, 2013)

No air gap.


----------



## Glenn (Jun 28, 2013)

Uncle Bob said:
			
		

> No air gap.


Agreed...that's an air break, not an air gap.  Although I don't think it's asking for an air gap for the same reason as a plumbing fixture (funk growing up on the outlet of the fixture).  An air break, I think, would be sufficient, and sufficient for freeze protection.  My only guess for the full air "gap" would be so it is readily visible that it's discharging while in the same room as the equipment.


----------



## Uncle Bob (Jun 29, 2013)

Glenn said:
			
		

> Agreed...that's an air break, not an air gap.  Although I don't think it's asking for an air gap for the same reason as a plumbing fixture (funk growing up on the outlet of the fixture).  An air break, I think, would be sufficient, and sufficient for freeze protection.  My only guess for the full air "gap" would be so it is readily visible that it's discharging while in the same room as the equipment.


I don't know about the UPC; but, 2009 IRC, P2803.6.1 The discharge piping serving a pressure-relief valve, temperature relief valve or combination valve shall:  #2.  Discharge through an *air gap *located in the same room as the water heater.


----------



## ICE (Jun 29, 2013)

Uncle Bob said:
			
		

> #2.  Discharge through an *air gap *located in the same room as the water heater.


I have heard of that and never seen it done except with commercial and a mop/floor/laundry sink.  Even with commercial we allow a direct shot to the outside.  I didn't find the requirement in the UPC and we don't enforce the IRC plumbing code.

Anybody know why this air gap is a good idea?


----------



## Keystone (Jul 2, 2013)

2009 IRC - P2803.6.1 Requirements for discharge pipe. The discharge piping serving a pressure-relief valve, temperature relief valve or combination valve shall:

1. Not be directly connected to the drainage system.

2. Discharge through an air gap located in the same room as the water heater.

3. Not be smaller than the diameter of the outlet of the valve served and shall discharge full size to the air gap.

4. Serve a single relief device and shall not connect to piping serving any other relief device or equipment.

Discharge shall terminate to air gap in room them to exterior, prevents possible contamination and freezing.

You all are on point;

Contamination from the funk build up / growth can easily bypass the rubber seat of the valve.

Air gap also provides ready visibility of a problem.

Freezing, air break has the potential to cause freezing.


----------



## Rider Rick (Jul 2, 2013)

I have in some cases approved the PTR drain line tied into the pan drain if the 3/4" PTR line was 12" below the pan where it teed in and sized up to 1" from the tee to laundry box drain and it had a 1" air gap.

It would need to be all copper or cpvc.

I was under the UPC.


----------



## Gregg Harris (Jul 2, 2013)

ICE said:
			
		

> I have heard of that and never seen it done except with commercial and a mop/floor/laundry sink.  Even with commercial we allow a direct shot to the outside.  I didn't find the requirement in the UPC and we don't enforce the IRC plumbing code.Anybody know why this air gap is a good idea?


Air gap only required when draining to the sanitary drainage to prevent a cross connection, it can #5 Discharge to the floor, to the pan serving the water heater or storage tank, to a waste receptor or to the outdoors.


----------



## Rider Rick (Jul 2, 2013)

Gregg Harris said:
			
		

> Air gap only required when draining to the sanitary drainage to prevent a cross connection, it can #5 Discharge to the floor, to the pan serving the water heater or storage tank, to a waste receptor or to the outdoors.


Good question.


----------



## Keystone (Jul 3, 2013)

I do not see any exceptions that would permit anything but an airgap.


----------



## Keystone (Jul 3, 2013)

"Discharge line must pitch downward from the valve and terminate at least 6" (152mm) above a drain where any discharge will be clearly visible."

Temperature and Pressure (T&P) relief valves - Support - Water Safety & Flow Control -Watts


----------

