Tpr Discharge line is PEX

Specific Inspection Topics Plumbing Inspections
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The following is specific to Florida, although the FBC is pretty much a direct copy of the IRC. Truth be known, the FBC is actually falling behind the IRC but that’s another topic for another time.
The issue we have here is not reading the entire code when it comes to T & P line piping, I have had this discussion with many code officials and inspectors and most get it wrong. The FBC has always stated that in cases where there is conflict within a code, that the most stringent shall apply. In the case of T & P line piping, you have to understand that the code states the manufacturer’s specifications shall take precedence unless the code is more restrictive, in which case the code would take precedence. Watts is one of the more common T & P manufacturer’s I run into, I have contacted them to inquire about there recommendations for the piping and they stated either “polypropylene or copper” was what they approved. I believe that’s what their lines are made of, the side mount line is poly and the topside mount line is brass.
That being said, the code reference goes like this(using residential):

***2010 Florida Building Code, Residential 102.1 General.
**Where there is a conflict between a general requirement and a specific requirement, the specific requirement shall be applicable. Where, in any specific case, different sections of this code specify different materials, methods of construction or other requirements, the most restrictive shall govern. *

*2010 Florida Building Code, Residential M2005.1 General.
Water heaters shall be installed in accordance with the manufacturer’s installation instructions and the requirements of this code. Water heaters installed in an attic shall conform to the requirements of Section M1305.1.3. Gas-fired water heaters shall conform to the requirements in Chapter 24. Domestic electric water heaters shall conform to UL 174 or UL 1453. Commercial electric water heaters shall conform to UL 1453. Oiled-fired water heaters shall conform to UL 732. *

*P2803.5 Combination *pressure-/temperature-relief valves. **
Combination pressure-/temperature-relief valves shall comply with all the requirements for separate pressure- and temperature-relief valves.

*P2803.6.1 ****Requirements for discharge pipe. **
The discharge piping serving a pressure-relief valve, temperature relief valve or combination valve shall: *
13. Be constructed of those materials listed in Section P2904.5 or materials tested, rated and approved for such use in accordance with ASME A112.4.1.

The manufacturer installation instructions are in clear conflict with the code as most require the piping to meet 250 degrees without distortion. Also, the code is in conflict with itself over what is required. ASME A112.4.1 is not a schedule of approved piping, but a schedule of temperature pressure type ratings for specific piping. ASME A112.4.1 being the more stringent application, the piping must meet the requirements of the manufacturer specifications both of the vale and water heater. In which case the line must be metallic and capable of handling temperatures at 250 degrees.

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Found this one today, it looks to me like there is a reduction smaller than 3/4", let alone the flexibility issue (this one wasn’t secured).

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I just found one that had white PEX installed and had the following listed on the pipe. The temperature and pressure rating for the pipe material is 160 PSI @ 73°F or 100 PSI @ 180°F or 80PSI @ 200°F. I wrote this one up because the TPR valve discharge would be over 210 degrees at over 150 PSI.

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That’s right. That is my opinion, based on fact, in writing. Not ANY water pipe is suitable. It is a Safety relief valve, not a water line. Similar to why you can’t use flex connectors for a discharge tube. The little tag glued to the flex connector says, “For use as a water supply fitting only.” A TPRV is not a water supply component.

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No matter what the material, the TPR discharge pipe termination must be visible (from the water heater.) This is to ensure through visual observation that it has not been capped.

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It’s not a water supply component but it is a component of the potable water system. Guess what is on the other side of a TPRV…potable water. For this reason the discharge pipe must me made of material suitable for potable water in that particular jurisdiction. PEX is an approved material in most jurisdictions.

The discharge pipe may drain onto the floor, outside or into a pipe that it approved for DWV in that jurisdiction. That could be PVC, cast iron, ABS and so on.

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Well, I’ve been doing more research and code does say any material used for hot water transport. I found more info that says if it is PEX or PERT, it must be one nominal size larger in diameter so, 1" on a 3/4" TPRV. It is certainly counter-intuitive that a pipe not rated for the temperature and pressure of the device is suitable. I don’t get that. But, there are many discrepancies in the codes. Code says that a bottom water heater strap has to be in the lower 1/3 of the tank and 4" above the gas controller. On a 59-60" tall water heater, if you go 4" above the gas controller you are well into the middle 1/3.
“The Titanic was built by experts who knew better than us also.” I can only defend what I can find in writing, so…

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New code 2018 IPC. Water heaters installed prior to 2018 can use 3/4” PEX.

It is suitable as the discharge pipe as it is not under pressure, the end is open. The ratings on the pipe are for a temperature and pressure. PEX pipe will be rated for a different pressure when it has 70F water in if than 159F water in it. This is an excellent example of why plumbers are licensed. Plumbers know this kind of information and this is a perfect example of someone interpreting a code without the knowledge of a trained professional.

Again this is just stupid. Seismic strap should be on the top 1/3 of a water heater and bottom 1/3. You can’t put a strap below a gas valve. Good thing plumbers have common sense. Ever see a 5 gallon water heater about 18” tall. Common sense goes a long way for the folks that actually install the equipment and don’t read about codes without the proper training.

What? :drooling_face:

The worlds most famous book has been interpreted differently by every reader for 2000 years. You may want to give your local plumbing inspector a call the next time you are confused about plumbing codes.

Please don’t. You will look foolish to someone educated. I strongly recommend you take the plumbing course as it may clear up many of your brilliant ideas.

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Welcome to our forum, Michael!..Enjoy! :smile:

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Thanks Larry

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Hey Martin, there’s no need to be insulting. The problem with these internet forums, people feel shielded. I did not insult YOU.
Anyway, I’ve been inspecting for 30 years. I’m sure I have seen more than you. I’ve been dealing with ridiculous codes for that long. That’s why they keep changing the codes every 3 years. One year something is ok and then they decide it is not ok.
I think I am educated, I can read. I am an engineer, so I’ve gotten some pretty heavy education. But, before we go down this road, regarding the water heaters I’m addressing here, the same brilliant plumber brought two 1" Pex tubes back into 1, in a Tee fitting and then terminated it through the original 3/4" pipe, so now that is considered reduced. The two in series 20 gallon electric heaters were
not secured in place, not even 1 strap.
The other Tankless water heater in the ATTIC, had no catch pan and there was no platform in front of it, just a myriad of wires and pipes. I couldn’t even get to the water heater to inspect it. AND that PEX from the TPRV undulated up and down causing a Trapped condition. And the 1" PEX also terminated through the 3/4" copper elbow. So, yes, everything about these water heaters is questionable. This house was re-built 9 years ago, 5100 sq ft, a major undertaking in an upscale area, it would have had to require permits and inspections. There’s no way a city inspector should have signed off on these water heaters. And this is not the only problem in the house.
As for codes, they should be written clearer and more specifically so as not to need “interpretation”. So, before insinuating what somebody else knows or doesn’t know, and getting defensive and insulting, how about having a discussion and ask questions…as if we were sitting in the same room with the same goals.
Mike

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The problem with these internet forums is you can pretend to be anyone you say you are. We do not know you, next to your name it says, “Non-Member Guest.” Act like a guest. If you were in my home I’d toss you out on your ear.

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Michael I think your mom is calling you up from the basement, your bowl of fruity pebbles is ready.

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They don’t make engineers like they use to. There was a time even an engineer would be capable of understanding that a open pipe can hold no pressure. Maybe Mikey is this kind of engineer.

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Mike…dont worry about it…

Both of these guys have a lot of history acting like this on this message board.

I dont know if they just are angry little men or frustrated or what…but I think they have not matured much since middle school

You are completely correct in that this board should be a place where people can discuss and decide what is best for our practice. It should be a place to help and build up rather than beat down and attempt to ridicule.

I recommend continuing to post on this board and either ignoring the little angry men or blocking them

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Thank you for that. I appreciate it. I have learned the hard way myself. The internet requires great restraint. Thx

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I too have had problems with understanding. I believe it was the 13 rules for installing a valve drain line.

The end has to be visible from where the hot water heater is. But can’t damage structure. If the hot water heaters on the second floor, how do you do that?

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The TPRV should discharge to a termination point that is readily observable. Often the water heater TPRV discharge pipe drains to the outside. Plumbing jurisdictions vary and the current codes today may not be the codes that were in place when the home was built. Some current codes (IPC)today require it discharge in the same room with the water heater through an air gap. Others (UPC) state the piping may discharge to the outside.

If the water heater is on the second floor it should discharge into a pan. The discharge piping will go into the pan and the drain from the pan will discharge safely elsewhere where it cannot do damage to the structure.

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Discharging a TPRV over a catch pan is prohibited. It doesn’t have to be visible from the water heater (like an electrical disconnect) it has to be to a conspicuous location. Preferably outside. It may discharge over a garage floor if the floor is sloped for drainage.

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IPC 504.6(5)

IPC 504.6(2).

This requirement is not in the code book. Can you provide the source for your “recommendations”

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