Thread: TPR Extension

It was my belief that any TPR extension needed to end above floor at six inches. If this is true than venting into drain would create the same issue that terminating less than six inches would cause. Does anyone have a differing opinion?

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I don't see a problem with it.

"10. Not terminate more than 6 inches (152 mm) above

the floor or waste receptor"


"5. 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."

Can someone please remind me what the reason is for not allowing the tpr to discharge into the pan?
Assuming there is a reason, of course.

Originally Posted by John Arnold

Can someone please remind me what the reason is for not allowing the tpr to discharge into the pan?
Assuming there is a reason, of course.

I am sure that there are a number of reasons why the TPR shouldn't discharge into the pan, one being that this could possible lead to corrosion of the bottom of the unit, shortening the lifespan of the equipment. It is a rare occasion when I find a water heater installed to the manufacturers specifications. Even when the installer leaves the installation instructions attached to the side of the unit they are usually not done right, leaving the instructions attached does give me something to show the buyers though...
In my area there usually isn't a pan or discharge tube installed at all, even more rare is to find a home where combustion air is supplied to the gas fired equipment...

"Yes, because the code prohibits it."


Where does the code prohibit discharge to the pan?

Aaron
Yes, I did look at the diagram you posted.

Thanks for posting the code for me.
The reason I asked is I could not (cannot) find that wording in my version of the code (2006 IRC).

P2801.5 Required pan.

Wherewater heaters or hotwater storage
tanks are installed in locations where leakage of the tanks
or connections will cause damage, the tank orwater heater shall
be installed in a galvanized steel pan having a minimum thickness
of 24 gage (0.016 inch) (0.4 mm) or other pans for such
use. Listed pans shall comply with CSA LC3.

P2801.5.1 Pan size and drain.

The pan shall be not less
than 11/2 inches (38 mm) deep and shall be of sufficient size
and shape to receive all dripping or condensate from the
tank or water heater. The pan shall be drained by an indirect
waste pipe having a minimum diameter of 3/4 inch (19 mm).
Piping for safety pan drains shall be of those materials listed
in Table P2904.5.

P2801.5.2 Pan drain termination.

The pan drain shall
extend full-size and terminate over a suitably located indirect
waste receptor or shall extend to the exterior of the
building and terminate not less than 6 inches (152 mm) and
not more than 24 inches (610 mm) above the adjacent

ground surface.

Alan,

While out on an inspection this afternoon I remembered your question, so I took a pic from a A.O. Smith water heater manual for you.

rick

I don't believe piping it into a discharge tank is ok as you cant see any leaking of the tpr.

The code wants the occupants to be able to see if the WH's TPR has "The Drip".

In addition, the code makers want to assure that should the TPRV be slow to activate, or fail to fully open (scaled over, or as in this case restricted by either the reinforced reflective insulation blanket material or items on the too-close food supply shelf, etc.), there is sufficient space/volume for a release of energy possible to avoid a steam flash event; and to keep the path clear and safe for the occupant or attendant to approach & shut down the (run-away) system without suffering serious scalding, burns or other injury to personel (such as before the vessel explodes).

I'm just happy to see a TPR valve with a line attached to it! Sometimes you have to let common sense take hold and provide a little guidance. I have seen many installations where the lined ended in the pan, it was really the only option.

The TPR should not leak and water should not stand in the pan. If you have water in the pan then you have a problem that needs attention. So the argument that leakage is going to cause damage to the unit is kind of weak. I agree that it needs to discharge in a location that can be seen.

It seems that the NC Plumbing Code does not prohibit the relief valve from discharging into the backup drain pan as long as the drain pan outlet is visible to the occupant. The pan acts like the air gap.

That's why I always qualify my responses with "in NC". What is done in NC does not mean squat anywhere else.

Originally Posted by James Duffin

It seems that the NC Plumbing Code does not prohibit the relief valve from discharging into the backup drain pan as long as the drain pan outlet is visible to the occupant. The pan acts like the air gap.

Actually, that is not what that says, read 4 again.

I will go through 4 if you need me to.

"I will go through 4 if you need me to."

Would you?

504.6 Requirements for discharge piping. The discharge piping serving a pressure relief valve, temperature relief valve or combination thereof shall:
- 4. Serve a single relief device and shall not connect to piping

serving any other relief device or equipment.

What is the purpose of that drain pan and its drain line?

Also this is rather screwy: 2. Discharge through an air gap located in the same room as the water heater either on the floor into an indirect waste receptor or outdoors.

Now, unless the water heater is listed for use outdoors ... how is the "or outdoors" going to be accomplished when it is required to be through an air gap "located in the same room" as the water heater? And when is the last time you have seen (installed, not in photos) a water heater listed for use outdoors?

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

Serve a single relief device
OK

Shall not CONNECT TO PIPING serving any other relief device or equpiment.
OK It does not CONNECT to any piping
The TPR drain line will be 6" above the floor of the pan.

I don't see the problem.

"2. Discharge through an air gap located in the same room

as the water heater either on the floor into an indirect

waste receptor or outdoors."

Lets reword it a little.

Discharge in the same room as the WH
through an air gap
that drains outdoors
or into a waste receptor.

At least thats the way I read it.

Let's do it this way:

- 504.6 Requirements for discharge piping. The discharge piping serving a pressure relief valve, temperature relief valve or combination thereof shall:
- - 1. Not be directly connected to the drainage system.
- - - Okay, it cannot be connected to the drainage system, it is okay there.
- - 2. Discharge through an air gap located in the same room as the water heater either on the floor into an indirect waste receptor or outdoors.
- - - Okay, it cannot be connect to *any* piping - not "directly" connected - as it is required to discharge through an air gap, which leaves it discharging into the open or a drain line designed for in accordance with minimum drain line sizes, which means it would be a minimum of 1-1/2" in size. The typical drain pan drain line is 3/4" to 1" in size.
- - 3. Not be smaller than the diameter of the outlet of the valve served and shall discharge full size to the air gap.
- - - This means that the discharge pipe may be 3/4" if the valve outlet is 3/4" and that it shall discharge full size (cannot be reduced in size) to the air gap.
- - 4. Serve a single relief device and shall not connect to piping serving any other relief device or equipment.
- - - This says the discharge line shall serve one single relief valve (it does only serve that one relief valve) and shall not connect to piping (obviously, it is required to discharge to an air gap) and that the piping it is connected to (obviously it is being treated as 'being connected to' some piping even though it is not "directly connected to" the piping, otherwise this section would not even be there, it would simply not be allowed to connect to *ANY* piping, which it apparently is, and thus the conditions put on it) and that the piping it is connected to shall not serve any other relief valve ... or ... "equipment". The drain pan drain line is connected to serve the water heater should it leak. Which makes that piping "serve ... other ... equipment".

Now let's go to 13.
- - 13. Be constructed of those materials listed in Section 605.4 or materials tested, rated and approved for such use in accordance with ASME AI12.4.1.
- - - This does not allow PVC to be used for the T&P discharge drain line as it is not one of the materials listed as 605.4 is for water distribution pipe, for which PVC is not approved. New for 2006 was a requirement that the drain pan drain line be of material listed for use as water distribution piping, which, on newer homes which used CPVC instead of PVC for the drain pan drain line may be able to get by on this one aspect only, but the drain pan and all other conditions would need to meet the code too.

- - - Additionally, the plastic drain pans are doubtful to be approved for use with that hot of water and be rated to that standard.

Lets say the WH sits directly on the floor (just say ceramic tile), no pan.
There is a floor drain near the WH (in the same room).
The TPR Discharge is <6" above the floor
and will drain into the floor drain (if it leaks)
My question is, can the drain line to the floor drain be made of PVC?
How about any of the drain lines in the house?

This
air gap located in the same room as the water heater either on the floor into an indirect waste receptor

Or this

or outdoors.

It does not need to be in the same room with an air gap

And some inspectors wonder why builders can't seem to get it right.

Originally Posted by Ted Menelly

This
air gap located in the same room as the water heater either on the floor into an indirect waste receptor

Or this

or outdoors.

It does not need to be in the same room with an air gap

Ted,

If the air gap is located in the same room, then the end of the discharge line is located in the same room as the water heater.

"2. Discharge through an air gap located in the same room as the water heater either on the floor into an indirect waste receptor or outdoors"

The air gap then discharges either on the floor into an indirect waste receptor OR to the outdoors.

Ever try to catch the discharge from a T&P into an air gap? You have to BEFORE you can pipe it to the outdoors, and, by the way, that is what they are using the drain pan drain line for, except that the drain pan drain line serves the drain pan and the T&P is only allowed to discharge to a pipe which serves only it.

Jerry, have you got "to" and "through" mixed up? After the air-gap it is no longer the discharge line, it is the receptor. As I see it the pipe connected to the T&P can not serve more than the one T&P. After the end of that pipe it is just a waste line.

"After the air-gap it is no longer the discharge line, it is the receptor."

Thats what I've been saying, at least trying to say.

2. Discharge through an air gap located in the same room as the water heater either on the floor into an indirect waste receptor

or outdoors.

In other words. Run the line to the exterior for discharge. Doesn't say it has to discharge in the same room first . It is either or.

I don't think it can be any more clear than that. It is either the underlined section or discharge it outdoors.

I am not sure what else you are saying.

Discharge through an air gap located in the same room as the water heater either on the floor into an indirect waste receptor or outdoors

Must meet this requirement:
Discharge through an air gap located in the same room as the water heater

Then you have a choice of
either

1st choice
on the floor into an indirect waste receptor

2nd choice
or outdoors

The requirement to discharge through an air gap applies to both choices.

"RC, TM, and the rest of the Density:

If you cannot simply take the code for what it says, why not opt for sending in an RFI to the ICC, so that they can tell you what I and JP have been telling you for 37 posts or so . . . ? Then you can argue with them."

What is fun about that.

My head is spinning but I need to ask this question.

In my area on most newer or new homes I see the discharge from the Hot Water Heater as follows. They run from the Temp Relief with 3/4 directly to the outside of the home and it is usually about 6 inches from the ground. No air gap ever. In reading this it sound like somewhere in the same room it has to drain into an air gap before it is piped outside. If thats the case and code is the IBC here and I don't have one only the 2006 IRC does anyone have the reference in the IBC. Thanks. Hope I am reading this wrong.

Originally Posted by William Brady

My head is spinning but I need to ask this question.

In my area on most newer or new homes I see the discharge from the Hot Water Heater as follows. They run from the Temp Relief with 3/4 directly to the outside of the home and it is usually about 6 inches from the ground. No air gap ever. In reading this it sound like somewhere in the same room it has to drain into an air gap before it is piped outside. If thats the case and code is the IBC here and I don't have one only the 2006 IRC does anyone have the reference in the IBC. Thanks. Hope I am reading this wrong.

You are reading it right. The early day this morning gave me an edge to get the thoughts going from some other folks. I cannot help myself sometime with Jerry and AD. Yes, air gap in the same room but I know no city that is doing it unless it is in a condo or town home some where. It just all depends on when they adopt in in there area.

I will check again but this city uses the IBC for residential and issues the CO. I know the IRC but have never read the other just know I hear them refer to it all the time for code. As a matter of fact last year I visited the Construction Industries Division Code Enforcement to make sure of a fire seperation issue question I had and they talked about the IBC. Maybe I'm wrong so now I have to go and find out again.

Thanks

Originally Posted by Ted Menelly

2. Discharge through an air gap located in the same room as the water heater either on the floor into an indirect waste receptor

or outdoors.

Read it the way it is written:

2. Discharge

through an air gap

located in the same room as the water heater

either on the floor into an indirect waste receptor or outdoors.

Let's go through it: "2. Discharge" the water coming out the T&P shall go (discharge)

"through an air gap" through an air gap, which is simply just a gap of air

"located in the same room as the water heater" the end of the T&P discharge line and the air gap are to be located in the same room as the water heater

"either on the floor into an indirect waste receptor or outdoors." the discharge stream coming out the end of the discharge pipe goes through a gap of air and can either go into an indirect waste receptor in the floor or to the outdoors

Now I ask again, with the discharge pipe indoors, the air gap indoors, HOW is the discharging stream of hot water going to get OUTDOORS? Through a big ol' hole in the wall?

Think, man, think.

Originally Posted by Jerry Peck

Read it the way it is written:

2. Discharge

through an air gap

located in the same room as the water heater

either on the floor into an indirect waste receptor or outdoors.

Let's go through it: "2. Discharge" the water coming out the T&P shall go (discharge)

"through an air gap" through an air gap, which is simply just a gap of air

"located in the same room as the water heater" the end of the T&P discharge line and the air gap are to be located in the same room as the water heater

"either on the floor into an indirect waste receptor or outdoors." the discharge stream coming out the end of the discharge pipe goes through a gap of air and can either go into an indirect waste receptor in the floor or to the outdoors

Now I ask again, with the discharge pipe indoors, the air gap indoors, HOW is the discharging stream of hot water going to get OUTDOORS? Through a big ol' hole in the wall?

Think, man, think.

Jerry the air gap inside yes. I siad in my last post I was just doing the early morning mind pump thing with you and AD. This has been discussed many times about the air gap and blah blah blah.

I know it is hard to believe but I concur and always did. Like Rick said to his post from AD. Why argue with the code creators "That's no fun"

As far as whether it should be in the city one is on.....sure...why not.... but if it has not been adopted as most cities around here have not then it is all just gibberish until they do. Just another explanation to the client about "code, no inspect yet in this city about this code".

Here is a water heater installation I inspected today with a "custom" drain pan. The relief valve dumps into the pan. This was passed by the plumbing inspection the first of the week. I did make a note that they had used the wrong type fitting to connect the pan liner to the drain.

James,

Is that blue smurf tube? If so, what is it being used for?

The main problem with that installation, like all similar installations, is that the water heater is not listed for being installed partially submerged and that pan is intended to have water in it.

The next problem is that the drain is PVC and not of the materials specified as being required.

Also not sure that the shower pan liner is rated for that use either as it likely is not rated for that temperature.

Then there is the fact that the end of the discharge pipe appears to be below the top of the 'pan' and it is required to be at least 2 x the diameter of the pipe above it, with that being 3/4" pipe the end would be required to be 1-1/2" minimum above the top of the 'pan'.

Then there is the fact that the shower pan liner does not go up and over the top of the wood as it should, which will allow water to get between the pieces of wood when water gets in that 'pan'.

Then there is the fact that shower pan liners are required to be installed on a floor which is sloped 1/4" per foot and not flat ...

And then ...

But other than those things ... ... and a few more ... sure, looks all okay and good to go.

Originally Posted by A.D. Miller

JP: While that may be true, the IRC seems to disagree . . .

That picture is the way I see Town Homes and condos set up. I have not seen a home set up like that yet,,,,,Well, old homes that someone added a pan to a new water heater in one of those raised closets and added a receptacle on the drain line and drained the HVAC condensation drain water, drain pan and the TPR drain water into it with an air gap.

Originally Posted by A.D. Miller

JP: While that may be true, the IRC seems to disagree . . .

I had a long post all typed out with the code references and everything showing that is incorrect and that the manufacturer's installation instructions and listing and labeling is REQUIRED to be followed, and some other pertinent information, and it all got lost in cyberspace ... so I am just going to direct you to the listing and labeling, and installation requirements sections for water heater in the plumbing, mechanical, fuel gas, and the electrical sections of the IRC and you will see that drawing does not depict what the code states.

Originally Posted by Jerry Peck

Ted,

If the air gap is located in the same room, then the end of the discharge line is located in the same room as the water heater.

"2. Discharge through an air gap located in the same room as the water heater either on the floor into an indirect waste receptor or outdoors"

The air gap then discharges either on the floor into an indirect waste receptor OR to the outdoors.

Ever try to catch the discharge from a T&P into an air gap? You have to BEFORE you can pipe it to the outdoors, and, by the way, that is what they are using the drain pan drain line for, except that the drain pan drain line serves the drain pan and the T&P is only allowed to discharge to a pipe which serves only it.

Jerry,

Used to work with someone that like to send out emails with large red type. No one paid any attention to her when she did that. Which are you trying to emphasize---the red or the blue? Liked your responses when you used the underline to make a point.

Originally Posted by Rich Goeken

Used to work with someone that like to send out emails with large red type. No one paid any attention to her when she did that. Which are you trying to emphasize---the red or the blue? Liked your responses when you used the underline to make a point.

Rich,

Appears you did not read through the posts leading to that post, therefore your reply is suspect.

I will clue you in:
- Go back and read and look at posts 1-24, looking for that larger red text.
- You did not find it did you?

Now, another clue for you:
- Go back and read and look at post 25, looking for that larger red text.
- Whoa! Dang! You just found it, didn't you.

Now do you understand why I used that large red text?

So colorful. Are you guys with the Rainbow Coalition?

My order of who to "believe" is the manufactures installation instructions, the applicable code, and the AHJ who can override the first two. It's not cool to write up a "problem" and then have the seller get your "problem" solved by calling the AHJ who says it is OK the way it is. Once the AHJ says it is OK then they are "the last man in" and the responsibility falls back on them. I'm sure there are some folks who will not agree...(talk about an understatement! )

Originally Posted by James Duffin

My order of who to "believe" is the manufactures installation instructions, the applicable code, and the AHJ who can override the first two. It's not cool to write up a "problem" and then have the seller get your "problem" solved by calling the AHJ who says it is OK the way it is. Once the AHJ says it is OK then they are "the last man in" and the responsibility falls back on them.

Almost there ...

That ONLY applies if the AHJ PUTS THAT IN WRITING, otherwise it means diddly squat because the next person from the same AHJ may say differently - and likely will.

I've had that happen and then started having them put it in writing ... they would not, and instead refer back to what the code wording was and go by it ... which was the same thing I was saying.

Only when they put it in writing is it an official interpretation.

Originally Posted by A.D. Miller

Nah, reformed commies . . .

Ok, commies I can deal with, the other,,not so much.

There is a difference in practicality and reality. I deal with reality and let the folks with more free time than me deal with practicality. ie....I don't have the time or inkling to get in a pissing match with the AHJ.

Once the air gap or six inches above splash back or floor (sanitary, potable protection, i.e. no yuckus backing up via discharge pipe, valve assembly, contaminating potable water system)...

It is no longer "discharge", beyond the sufficiently provided air gap or space to free air where energy may be dissapated, released: it (the products of discharge from the TPRV) is "transformed" into drainage after/at the receiving end of the discharge pipe or tube. where exposed to atmosphere and free air

The receiving air gap or receptor has at its output, drainage, hot water drainage capable, but not steam -- it is not a transporter of discharge.