# Pressure Relief Discharge to Garage Slab



## JMORRISON (Apr 23, 2010)

Do you allow water heater pressure relief discharge to go to garage slab?


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## Mule (Apr 23, 2010)

Nope! We feel that this would be in a manner that would cause personal injury.

Now we do allow the drain pans to dump into the lower section of the garage.


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## FredK (Apr 23, 2010)

No.

How come no is to short an answer???


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## Mule (Apr 23, 2010)

How many of you require the discharge line to discharge through an air gap located in the same

room as the water heater?

It's required by code!

We don't!


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## mtlogcabin (Apr 23, 2010)

Yes



> How come no is to short an answer???


You to have 10 characters t post an answer


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## JMORRISON (Apr 23, 2010)

I am still twisted on this.  These are SFR with 3' foundation wall and joists dropped so garage and entry have no steps to house.

Water heater in alcove accessed from the garage.  If PR drain to outside by the time it gets there it is below outside grade.

I have required hub drain with trap primer in the past but we have seen a few trap primers fail and trap dry out and stink. I have allowed pan to dump to garage floor.

If PR dumps to garage it would certainly be noticed when there is problem.  My highly fuel efficient and "green machine" (Ford Expedition) brings more white water daily into garage than the PR will probably ever dump.


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## 88twin (Apr 23, 2010)

yes

2009 IRC P2803.6.1 specificly (sic) #5, #6, #10

allowed by #5

we do not feel #6 applies because of #10


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## skipharper (Apr 26, 2010)

Sure, allowed by code.


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## Moscow (Apr 27, 2010)

I allow it to dump not more then 6 inches from the garage floor.

Justin


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## peach (Apr 27, 2010)

yes.. garage slab is observable.. does not (usually) do damage to the structure..  pretty common application


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## Pcinspector1 (Apr 29, 2010)

I agree with the peach, I would allow it, most garage floors these days are pitched to the front door, would have to be a min 6" from the floor. I think its visable and don't think much water damage would occur.


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## Bootleg (Apr 29, 2010)

Pcinspector1 said:
			
		

> I agree with the peach, I would allow it, most garage floors these days are pitched to the front door, would have to be a min 6" from the floor. I think its visable and don't think much water damage would occur.


Also water heater would need to be 18" off of garage floor.


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## Mule (Apr 29, 2010)

Bootleg said:
			
		

> Also water heater would need to be 18" off of garage floor.


Maybe....maybe not!


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## Bootleg (Apr 29, 2010)

Mule said:
			
		

> Maybe....maybe not!


Mule,

Would this be if the water heater is gas or electric?


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## Mule (Apr 29, 2010)

Even if it's gas it could possibly still be on the garage floor.

I'm making you think now aren't I!  

Let me know when you give up.


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## vegas paul (Apr 29, 2010)

Mule - if the WH is listed as flammable vapor ignition resistant, then put it on the floor!


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## Mule (Apr 29, 2010)

Hey!!!!! I was trying to get Bootleg to do some research!! 

You done went and spoiled my fun!


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## vegas paul (Apr 29, 2010)

But Mule, Everyone knows that it's best to raise the WH up as high as you can... cuz hot water rises, and the higher you place the WH, the less you have to heat it... So if you have to heat it 18" less, then you save money!  Maybe I better get my thermodynamics book out and review it.  Been too long since I Boyle'd (sic) water!


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## Bootleg (Apr 29, 2010)

Mule said:
			
		

> Hey!!!!! I was trying to get Bootleg to do some research!! You done went and spoiled my fun!


Mule,

If the water heater is electric would you approved it on the floor?

What about the code people that say an electric water heater is a source of ignition.


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## Mule (Apr 29, 2010)

No.  We had a sit down discussion and determined that electric water heaters with their contact's, elements and wiring have the potential for being a souce of ignition by arcing or shorting out.

From the 2006 IRC

M1307.3 Elevation of ignition source. Appliances having an

*ignition source* shall be elevated such that the source of ignition

is not less than 18 inches (457 mm) above the floor in garages.

For the purpose of this section, rooms or spaces that are not part

of the living space of a dwelling unit and that communicate

with a private garage through openings shall be considered to

be part of the garage.

From the definitions section of the 2006 IRC

IGNITION SOURCE. A flame spark or hot surface capable

of igniting flammable vapors or fumes. Such sources include

appliance burners, burner ignitors *and electrical switching*

*devices.*


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## Bootleg (Apr 29, 2010)

Mule,

I guess that would make a refrigerator, freezer, washer and drier a source of ignition and need to be elevated also?

At this time I only required electric and gas water heaters if not flammable vapor ignition resistant.


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## Mule (Apr 29, 2010)

Bootleg said:
			
		

> Mule,I guess that would make a refrigerator, freezer, washer and drier a source of ignition and need to be elevated also?


Yep! Crazy but I believe they would be an ignition source.

And we require the same as you.


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## peach (May 4, 2010)

Gotta kinda go with Mule on this...   the appliance is not the only thing in a garage that can produce flammable vapors... unless you never store a car or lawnmower in your garage.


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## Glennman CBO (May 5, 2010)

We're in the UPC. Electrical devices are not included in the verbage in what needs to be elevated (as far as water heaters are concerned). 508.14 states that "all burners and burner ignition devices" shall be elevated min 18" above the floor. It does state however, in 506.1, that water heaters deriving heat from other sources shall be installed in accordance with approved standards. There may be other sources that require elevation of electric water heaters, but in our state the IRC is not one of them, at least the way I understand it. Even ch 24 covers only fuel gas equipment, therefore, the "ignition source" there would only include gas flames. Food for thought.


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## FredK (May 5, 2010)

The only thing in the garage when I do a final is the water heater.  Usually sitting 18" off the floor.

Leave all those other things that might go in there out of the equation.


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## Bootleg (May 5, 2010)

Glennman CBO said:
			
		

> We're in the UPC. Electrical devices are not included in the verbage in what needs to be elevated (as far as water heaters are concerned). 508.14 states that "all burners and burner ignition devices" shall be elevated min 18" above the floor. It does state however, in 506.1, that water heaters deriving heat from other sources shall be installed in accordance with approved standards. There may be other sources that require elevation of electric water heaters, but in our state the IRC is not one of them, at least the way I understand it. Even ch 24 covers only fuel gas equipment, therefore, the "ignition source" there would only include gas flames. Food for thought.


Glennman,

Under the UPC you don't require an electric water heater to be elevateted in a garage?

I'm in Washington State under the UPC also and most of the JHA requied the water heater to be elevated I only know of one who does'nt require an electric water heater to be elevated.

I don't see the life safety risk with an electric water heater sitting only on R-10 ridgid insulation on a garage slab.


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## JBI (May 5, 2010)

Mule, Excellent use of the 'Definitions' section. Too often we answer (or engage the thought process) using only the definitions we carry around in our heads. The definitions sections in the codes are there for a reason, and you drove that point home on this one.


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## Glennman CBO (May 5, 2010)

Bootleg,

I agree. I'm relatively new in my current setting. We have only had an issue with one electric water heater in a garage that has come up since I started here. When I brought up these code sections as stated in my post, no one could argue with it.


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## Bootleg (May 5, 2010)

Glennman,

I'm going to stick with what Mule posted and require that electric water heater be elevated until I have a code that says otherwise.


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## Mule (May 5, 2010)

JBI said:
			
		

> Mule, Excellent use of the 'Definitions' section. Too often we answer (or engage the thought process) using only the definitions we carry around in our heads. The definitions sections in the codes are there for a reason, and you drove that point home on this one.


Thank you JPA...I mean JBI!  

Sometimes I sling out something worth reading! :???:


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## peach (May 5, 2010)

an ignition source can be a spark from the electric ignition of an electric water heater igniting the gas fumes in the garage..  gasoline fumes are heavier than air and settle/collect near the floor.


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## Glennman CBO (May 5, 2010)

Bootleg,

Better to err on the side of safety. BTW, what specific code section would you use to back it up, should you be challenged? Just curious.

Good discussion.


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## Bootleg (May 5, 2010)

Glennman CBO said:
			
		

> Bootleg,Better to err on the side of safety. BTW, what specific code section would you use to back it up, should you be challenged? Just curious.
> 
> Good discussion.


Glennman,

Good question!

I would use the code Mule quoted:

From the definitions section of the 2006 IRC

IGNITION SOURCE. A flame spark or hot surface capable

of igniting flammable vapors or fumes. Such sources include

appliance burners, burner ignitors and electrical switching

devices.


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## mtlogcabin (May 6, 2010)

Bootleg

Now you have to apply the definition to a code section and unless you are using the Mechanical, Plumbing or Fuel Gas portions of the IRC I don't believe you will prevail if challanged JMHO

Good try though

BTW we are under the UPC and require electric water heaters located in a garage to be elevated. How do we do it? The contractors do not own a code book :lol:


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## Mule (May 6, 2010)

What does the UMC say about sources of ignition in the garage.

Just wondering since the section I quoted came from the mechanical section of the IRC.


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## Mule (May 6, 2010)

Okay, I dug out the really old UPC...1997

*Section 510.0 Protection From Damage*

510.1 Water heaters generating a glow, spark, or flame capable of ignighting flammable vapors may be installed in a garage, provided the pilots, burners or heating elements, and switches are at least eighteen (18) inches above the floor level.

Does your newer UPC have the same lanquage???


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## Bootleg (May 6, 2010)

Mule said:
			
		

> Okay, I dug out the really old UPC...1997*Section 510.0 Protection From Damage*
> 
> 510.1 Water heaters generating a glow, spark, or flame capable of ignighting flammable vapors may be installed in a garage, provided the pilots, burners or heating elements, and switches are at least eighteen (18) inches above the floor level.
> 
> Does your newer UPC have the same lanquage???


Mule,

It looks like it was taken out.

The 2006 UPC 508.14 Installation in Residential Garages.

(1) Gas utilization equipment in residential garages and in adjacent spaces that open to the garage and not part of the living space of a dwelling unit shall be installed so that all burners and burner-ignition devices are located not less than 18 inches above the floor unless listed as flammable vapor ignition resistant.

It looks like mtlogcabin is right that under the 2006 UPC that an electric water heater is to code when on the floor in a garage of a SFR.


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## peach (May 7, 2010)

someone had a good lobby at the last UPC hearings.


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## D a v e W (May 10, 2010)

I agree with all, electric water heaters up, gas non-fvir up, tp to garage floor sloped to exterior ok.


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## JMORRISON (May 10, 2010)

View attachment 125


Here is schematic of electric water heater. In Washington State this sits on 2" insulated pad. The thermostat sits behind a plastic shield, a bunch of insulation and the metal cover. Under UPC language I allow to be on floor.
	

		
			
		

		
	

View attachment 125


/monthly_2010_05/fetchDocument..jpg.c5000efb0cde85afcd1581971eef0525.jpg


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## FredK (May 10, 2010)

Just to put the electric heater in prospective. The heating unit is not at ground level so be careful asking for a stand.


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## Glennman CBO (May 10, 2010)

JMORRISON,

Agreed.


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## Alias (May 10, 2010)

JMORRISON said:
			
		

> Do you allow water heater pressure relief discharge to go to garage slab?


Funny, I was just having this discussion with a happy homeowner this AM.  And the answer is:

No.  Must be piped to outside, CPC 608.5.

Sue, where the west still lives...............


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## pwood (May 10, 2010)

Alias said:
			
		

> Funny, I was just having this discussion with a happy homeowner this AM. And the answer is:No. Must be piped to outside, CPC 608.5.
> 
> Sue, where the west still lives...............


sue,

   608.5 also says "other approved locations"  i have approved other locations!


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## jim baird (May 11, 2010)

I have OK'd the garage floor discharge terminal but not right by the door where people come and go routinely.


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## Mule (May 11, 2010)

jim baird said:
			
		

> I have OK'd the garage floor discharge terminal but not right by the door where people come and go routinely.


Ditto on Jim's answer.


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