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Bull head end of T rules/codes

mike chaconmike chacon Member Posts: 17
What is code for entering bull side of T on potable water and hydronics?


  • Mark EathertonMark Eatherton Member Posts: 5,584

    Que pasa mi amigo:-)

    To the best of my knowledge, and as it pertains to the plumbing code, that focus is very blurry due to the lack of using it on a regular basis, but it USE to be legal to do so. You have 70 PSI of driving force behind the water, and it WILL go where you want it to, and KEEP going there.

    In a closed loop system, it USE to be illegal, but when modcon boilers were introduced, the AHJ's were SO confused, that instead of trying to educate themselves so they could tell the difference between an illegal BH tee and a primary secondary connection, they did away with the whole section in the code that addressed the BH tee situation.... Sad day in codesville in my humble opinion.

    As for your next anticipated question, YES, it absolutely DOES make a difference. If bull headed, the flows will constantly keep changing, because as you remember from class, water is like my ex brother in law. Wet lazy and stupid. He MUST be show what direction to go, because if he has to make up his simple mind, it will keep changing because the pressure drops related to the circuits keeps changing as well.

    The ONLY exception I allow to this rule, is in situations where the BH tee is being used to determine wether the flow goes to a DHW indirect tank, or to a space heating load. Under this scenario, the flow WILL be locked into the load (forced by dedicated prioritized pumps) and will not deviate.

    To all of my friends here on the Wall, my apologies for being so thin as of late. My new positions with IAPMO/RPA is consuming my every waking hour. I knew I was in for a rough ride initially when I took this position. Hopefully, things will smooth out now.

    The good news is, that we are making some fantastic progress in assembling the 8 committees that I will be charged with keeping busy and productive. We have a GREAT stable of guys (and gals) and are marching forward. This NEW RPA is going to make some indelible marks on life, good beneficial marks. Come join us won't you?

    Visit the site at and click on the Committee's button and see if there a place for you at one of the tables. This group is BY the members, FOR the members. Our annual conference/meeting/education track is coming together for September 18 thru the 20th and I think it is going to knock your socks off.

    Mark your calendar now and see us in Philadelphia.

    It's not so much a case of "You got what you paid for", as it is a matter of "You DIDN'T get what you DIDN'T pay for, and you're NOT going to get what you thought you were in the way of comfort". Borrowed from Heatboy.
  • mike chaconmike chacon Member Posts: 17
    Thanks Mark

    Nice to hear from you. Congrats on your new position. Hope to run into you soon. Thanks for the info. Mike
  • Bob HarperBob Harper Member Posts: 732
    2009 IRC

    M2101.7 Prohibited tee applications- Fluid in the supply side of a hydronic system shall not enter a tee fitting through the branch opening.

    Nothing noted in the IPC about potable water piping and tee orientation.

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