1. #1
    MembersZone Subscriber

    Join Date
    Jan 2003
    Canuck Expat May be anywhere

    Default American hydrant thread name

    Can anyone tell me the proper nasme for the thread on 1 1/2 and 2 1/2 hydrant and hose fittings. I am trying to crossover some US Hydrants here to accept British Instantaneous fittings and I need the name of the type of thread coming off the 2 1/2" outlet on the hydrant. In Canada, we used to call it FHT for fire hose thread. No one in this part of the world (Middle East) seems to have a clue about it. I appreciate any help
    Thank you

  2. #2
    Forum Member
    BCmdepas3280's Avatar
    Join Date
    Mar 2001


    They call it NST (National Standard Thread) but they also have a corser thread that is called bastard thread.
    IACOJ Membership 2002

    Mike IAFF

    The beatings will continue until the morale improves

  3. #3
    Forum Member

    Join Date
    Dec 2002
    Essex Junction, Vt.


    Once you step out of fire dept. circles (where it is indeed referred to as NST), the official engineering designation is "NH" for National Hose. The 2 1/2" would be specified 2.5-7.5NH (2 1/2 nominal size, 7 1/2 threads per inch, National Hose thread form.) 1 1/2 would be 1.5-9NH, although it is common (at least around here) for 1 1/2 to be "Iron Pipe" instead of "National Standard". In this case, it would be designated 1.5-11.5NPSH. This will actually thread onto an equivalent size taper pipe thread (NPT).
    Essex Junction Fire Dept.

  4. #4
    Junior Member

    Join Date
    Apr 2003
    Dayton, PA, USA


    Originally posted by Ltmdepas3280
    They call it NST (National Standard Thread) but they also have a corser thread that is called bastard thread.
    hahahaha that hilarious, hahahaha, even if it is true, its still hilarious, lol

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