Floor drain for T&P relief valve

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by nukeman, Nov 20, 2009.

  1. nukeman

    nukeman Nuclear Engineer

    Joined:
    Nov 20, 2009
    Occupation:
    Nuclear Engineer
    Location:
    VA
    Hi guys,

    New to the forum. The situation that I have is that I have a water heater (electric) that is located under the stairway closet in the basement. We had the T&P lift a couple months back and flooded the closet (no drain), soaked the drywall, carpet, etc. This has kind of brought about a full basement remodel (we wanted to do it sometime and this gave us an excuse). For the old waterheater, I believe the thermostat is what failed. In addition to the T&P lifting, the waterheater also split open. I have a new WH in there now, but the T&P is still aimed at the floor with nowhere to really go.

    Anyway, what I would like to do is to add a floor drain for the T&P to discharge into (if it ever happens again) and also give a place to drain the pan for the hot water heater (if there is condensation or small leaks).

    I am in Virginia. The plumbing code can be found here:
    https://www2.iccsafe.org/states/Virginia/Plumbing/Plumbing_Frameset.html

    No local changes to this code that I know of. The problem that I see relates to section 802.3 "Waste receptors shall not be installed in bathrooms or toilet rooms or in any inaccessible or unventilated space such as a closet or a storeroom."

    I know that it is fairly common to put the WH under the stairs (probably not the best location, though). What do people typically do in this situation? I know that where the T&P is allowed to discharge varies. Where I am located it is allowed to discharge to the floor, an indirect waste receptor, or to the outdoors. Since the closet is in the center of the house, running it outside would be difficult.

    The options that I can think of:

    - add a floor drain/sink in the adjacent (unfinished) laundary area. There is already a floor drain in the center of the room, but perhaps something closer to the WH would be better.

    - relocate the WH to the furnace room. There is already a 2" indirect waste receptor there (for the AC condensate). Running the plumbing and electrical there would be no problem, but I don't know if I would maintain the clearance needed to service the furnace and WH. In addition, the only location in that room to put the WH would make it difficult to reach the water shutoff valve for the house.

    Sorry for the long post, but I wanted to try to give all of the info needed. If there is something I forgot to mention, just let me know. This work is done under a permit. Since their job is not to design, I have to come up with something that should meet code in order for them to approve it.

    Thanks,

    Kent
     
  2. Gary Swart

    Gary Swart In the Trades

    Joined:
    Sep 1, 2004
    Location:
    Yakima, WA
    Here's what I have in my basement for this situation. There was an existing floor drain about 4 feet from where I wanted to relocate my water heater. I made a 2-1/2 x 5' x 6" basin enclosing the drain. On the end where the heater was to be, I added a 4" step-up from the floor. I now can drain the tank and handle the T/P without a flood. To keep the basin from leaking, I got a waterproofing product from HD and it worked great! I changed to tank drain to a full 3/4" with a ball valve and plumbed it down to the basin floor so when I drain/flush the tank, I can really get a huge flow without a problem. One of my smartest ideas.:D
     
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  4. nukeman

    nukeman Nuclear Engineer

    Joined:
    Nov 20, 2009
    Occupation:
    Nuclear Engineer
    Location:
    VA
    Thanks for the input. Something like that may work for me, my floor drain is about 10' or so away, though. I could simply run the line through the closet wall and have it point down to the laundry room floor and let the water run to the floor drain. I would like something a little cleaner, though.

    I'm not affraid to tear up concrete and run a new line. I have to go through that process to relocate a shower drain anyway. I wish I could just put the waste receptor in the closet. Perhaps the concern is the trap drying out and having sewer gases fill the space? If so, maybe I could use a trap primer and maybe add a louvered door for ventilation?

    I could post some pics or a diagram of what I am dealing with if that would help.

    Thanks!
     
  5. Inspektor Ludwig

    Inspektor Ludwig Journeyman/Inspector

    Joined:
    May 11, 2006
    Location:
    In the good ol' UPC
    You could run your T+P to your laundry standpipe as long as the t+p drain is higher than the opening for the stand pipe. Or you could run it outside if you have a place for the pipe to go. The pipe has to remain level or drop down but it can never be ran up.
     
  6. nukeman

    nukeman Nuclear Engineer

    Joined:
    Nov 20, 2009
    Occupation:
    Nuclear Engineer
    Location:
    VA
    Due to the layout, that would be difficult. The washer is even further away than the floor drain. It would require running the pipe across a doorway unless you could run up (which you can't). I do understand that GA does allow you to run up if you have no other options. That doesn't apply here nor do I think it is a good idea.

    Thanks for the ideas. I really appreciate it!

    I guess the other option wpuld be to relocate the WH to the laundry area. That area is the only unfinished portion of the basement with the exception of the furnace room. This way I could just dump the T&P to the floor.

    One of the reasons why I would like to add an additional floor drain is I have an old dehumidifier that I would like to hook up and would be great to have a place for the condensate to go.

    The remaining option that I can think of is to try to get an exception to place the waste receptor in the closet. hmm...

    Keep the ideas coming! The ones so far have been really good. Boy, putting WHs in a closet like this gets them out of the way, but it sure makes it a pain with dumping the T&P to a good place.

    EDIT: Here is what I am dealing with in terms of layout. Current floor drain near center of utility room.

    [​IMG]
     

    Attached Files:

    Last edited: Nov 20, 2009
  7. hj

    hj Moderator & Master Plumber Staff Member

    Joined:
    Aug 31, 2004
    Occupation:
    Plumber
    Location:
    Cave Creek, Arizona
    t&p

    Dumping the T&P discharge onto the floor is NEVER a good idea, and is not permitted here. If you move the water heater, dump the discharge into the washer's standpipe. There is a "safe" way to go up over the door, actually go up to the ceiling and around the corner, but it would require a "thinking inspector" to approve it, and they are few and far between.
     
  8. nukeman

    nukeman Nuclear Engineer

    Joined:
    Nov 20, 2009
    Occupation:
    Nuclear Engineer
    Location:
    VA
    Thanks, hj. I agree that a floor drain or standpipe is probably the best option. Perhaps I can locate the WH next to the washer. The hot and cold lines run across the bottom of the joists between the mechanical room and the utliity room (straight shot) and everything branches off from those two lines. This means that it would be pretty straightforward to move the WH anywhere along that line.

    I suppose that I wouldn't need a drip pan as the utility room has a concrete floor and the walls are cinder block. Wouldn't have to worry about damage due to a leak.

    I'm leaning towards the standpipe idea. It sure would be nice to eliminate busting up more concrete than needed. Perhaps I could even locate the dehumidifier in the same area and tie it into the standpipe too.

    Thanks for the great advise! I'll let you know how it works out.

    Kent
     
  9. nhmaster

    nhmaster Master Plumber

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    Jul 30, 2008
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    Tech. Instructor
    Location:
    S. Maine
    Ne he can not! The T&P drain has to be in the same room as the appliance. Unless the laundry stand pipe is unused he can not run two appliances into it either.
     
  10. G60

    G60 New Member

    Joined:
    Nov 12, 2009
    Location:
    DC
    I am no expert, but I have been reading up a bit on this here: http://www.nachi.org/forum/f22/do-you-allow-tpr-discharge-into-wh-pan-40155/ and elsewhere.

    mine, a second floor electric, T+P currently goes to the floor drain, but this makes it not really possible to a) see if the T+P it is leaking, and b) not really conducive to yearly testing, both of which are are considered important. In some locations you are allowed to drop a copper pipe to 6 inches above a plumbed drip pan in some places you are not. the advantage of doing that is you can see leaks and you can test.
     
  11. hj

    hj Moderator & Master Plumber Staff Member

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    Plumber
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    Cave Creek, Arizona
    t&p

    If the discharge HAD to be in the same room as the heater, then it would be IMPOSSIBLE to obey the other part of the paragraph which states, "OR to a location where the discharge will not cause damage". Here, that usually, (acutally almost every time), means to the exterior of the building, which is NOT the same room as the heater.
     
  12. nukeman

    nukeman Nuclear Engineer

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    Nov 20, 2009
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    Nuclear Engineer
    Location:
    VA
    Peter Griffin: I have read that the dischage is supposed to be in the same area as the WH. I have not seen the limitation on the standpipe. Can you point me to the code on that? It seems like you could possibly wye into the standpipe, but I may be wrong there.

    G60: Thanks. I have been reading about your situation too. You have a bigger chance of damage since it is on the 2nd floor. I did read once about someone else that had their WH on the 2nd floor like you do (was in a closet). What they did is they built basically a small shower pan and set the WH on top. That way leaks or the T&P would drain into the 1.5" or 2" shower drain. Eliminates the drip pan and also eliminates some piping. Maybe something like this would work for you. You could route your condensate lines into the pan too if you wanted.

    Although it isn't too likely that the T&P will open again in the near future, but I want to be protected if it does. I was outside when it happened and luckily I came down to the basement to put a tool away. We were then getting reading to leave for the rest of the day. If it happened while we were away or during the night, it would have been much worse!

    Anyway, cost or labor is not a factor. I just want to do it right.

    Thanks, guys.

    EDIT: on my code, it says that the T&P must discharge though an air gap located in the same room as the WH (504.6). In areas subject to freezing, I am also required to go throgh an air gap in a conditioned space and through an indirect waste receptor if I want to run it to the outdoors. (also 504.6).
     
    Last edited: Nov 22, 2009
  13. hj

    hj Moderator & Master Plumber Staff Member

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    standpipe

    You CAN "Y" into the standpipe, but only to create a second parallel standpipe. The water heater T&P discharge HAS to terminate at least 1" above the standpipe, it cannot hang inside it. And as stated in the code, the discharge MUST go to a location where it will NOT cause damage, and a discharge to the floor will USUALLY cause damage unless it is a completely unfinished area, with no stored items on the floor, and a floor drain somewhere.
     
  14. nukeman

    nukeman Nuclear Engineer

    Joined:
    Nov 20, 2009
    Occupation:
    Nuclear Engineer
    Location:
    VA
    That makes sense. So, put the wye towards the bottom of the current standpipe, add an angle to bring the wye side portion vertical and then extend to whatever vertical height to make a parallel standpipe. Bring the T&P above this line (minimum 1"-1.5") and secure it.

    The other option may be to add a floor drain or floor sink near where the WH is re-located.

    Thanks for the input!
     
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