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Max. Vent

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  • #16
    Re: Max. Vent

    Originally posted by drtyhands View Post
    A little object for discussion.

    Our maximum length we can run a 2" horizontal vent is 1/3 the total vertical length of 120'(40')

    1-1/2"s maximum length is 1/3 of the total vertical length of 60'(20')

    Here is what we have.

    From the vent stack there is 30 feet of 2" horizontal vent piping to a W/C.There is one branch that comes off of that 2" vent and runs another 30' horizontal to a hand sink this fixture only needs 1-1/2".

    The 1-1/2" vent needs to be increased 1 pipe size to increase the allowable distance to an undetermined length(not in the chart,most say infinity).

    So now the hand sink vent is 2" at 30'

    The W/C is 2" at 30' which is under the maximum.

    Could a person say that the 2" vent line is now sixty feet and needs to be increased one pipe size.

    I say "no" the larger 2" from the hand sink is only to increase that branch and does not affect the atmospheric pressure on the W/C vent.

    Hope I did not make it too confusing.If I did you guys know it won't be the first time
    If I'm reading this right you are fine. Your 2" toilet vent would be 30' long (fine). Your hand sink vent would be a total of (and if this is if the branck was at the end of the toilet vent) another 30' (only 10' that must be 2"). Thus the hand sink vent would be a total of 40' (fine). This is all if I'm reading this right. Keep in mind that the building's vent must equal the surface area of the main building drain.

    I haven't read the rest of the posts, so pleases excuse me if this is a repeat of info.
    the dog


    • #17
      Re: Max. Vent

      Adam, a ciircuit vent is just one the doesn't loop back to the vent stack and goes through the roof on it's own...I figured I just throw it out there not knowing how high up the roof is, nor that it was a remodel.
      We don't do waste and vent combo's here, only wet vents on bath groups.
      It's a matter of Mars vs Venus...I might as well be citing code from Uganda from your perspective regarding this.


      • #18
        Re: Max. Vent

        Just learned something today,thanks Duck.No one has used that term around me before,and I took a code class back in the eighties.

        This is a renovation of a quadrant of the 15th floor af a medical building.It's 3 suites combined.Full gut and replace,usually is with tenant improvements.