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What is my Pipe Size

Shuttle
Shuttle Member Posts: 24
in Strictly Steam
I am trying to determine the size of the main in my basement so I can purchase Pipe insulation.



I am trying to figure out what size insulation to buy from statesupply.com



my pipe outer diameter is about 2 1/2 inches (is this the size??)



or isit the inside diameter? (about 2in???)



statesupply only carries 2"

Comments

  • Rod
    Rod Posts: 2,067
    edited January 2011
    Pipe Sizing Chart

    Hi - The easiest way is to measure circumference. Wrap a strip of paper around the pipe and mark where the end of the strip touches and then measure the length from the end of the strip to the mark.  Consult the attached chart for the pipe size.

    Insulation- There was some discussion on this recently . Here is a source that Gerry Gill suggested. http://buyinsulationproducts.com/

    - Rod
  • BobC
    BobC Member Posts: 5,502
    Pipe size

    A pipe with 2.37" outside diameter is a 2" pipe.



    Bob
    Smith G8-3 with EZ Gas @ 90,000 BTU, Single pipe steam
    Vaporstat with a 12oz cut-out and 4oz cut-in
    3PSI gauge
  • Shuttle
    Shuttle Member Posts: 24
    edited January 2011
    Still Confused!

    Now back to square One!



    according to the chart I have 2 1/2 " Pipe (9 inch circumference)



    According to BobC I have a 2" Pipe (2 1/2 " OD!!! )



    That is my original question (which of the two is it?)
  • Dave in QCA
    Dave in QCA Member Posts: 1,788
    edited January 2011
    Read the chart again....

    And remeasure your pipe.

    The first column is the nominal pipe size, This is the "name" of the pipe, although it does not measure this size.  The 2nd column, of course is the actual circumference.  The 3rd column is the actual diameter.



    It is a mathematical impossibility to have a pipe, or any cylinder for that matter, that has a circumference of 9.032" and a diameter of 2.375"  

    You are doing something wrong.....
    Dave in Quad Cities, America
    Weil-McLain 680 with Riello 2-stage burner, December 2012. Firing rate=375MBH Low, 690MBH Hi.
    System = Early Dunham 2-pipe Vacuo-Vapor (inlet and outlet both at bottom of radiators) Traps are Dunham #2 rebuilt w. Barnes-Jones Cage Units, Dunham-Bush 1E, Mepco 1E, and Armstrong TS-2. All valves haveTunstall orifices sized at 8 oz.
    Current connected load EDR= 1,259 sq ft, Original system EDR = 2,100 sq ft Vaporstat, 13 oz cutout, 4 oz cutin - Temp. control Tekmar 279.
    http://grandviewdavenport.com
  • crash2009
    crash2009 Member Posts: 1,484
    Forget about the diameter

     unless you have a micrometer.  I had to measure all mine for insulation too.  I used my wife's canvas measuring device, that she uses for sewing.  Measure the circumferance, that's the distance all the way around the pipe. 

    a two inch pipe is about seven and one half inches (7.461")

    a two and a half inch pipe is about nine inches (9.032")

    I don't blame ya for being confused.  Decimals and fractions don't belong on the same page, unless you have dual (USA/CAN) citizenship. 
  • Dave in QCA
    Dave in QCA Member Posts: 1,788
    Agreement

    Measuring the diameter is VERY difficult.  I use 2 straight sticks of wood, a ruler or rigid measuring tape, and it takes 3 hands.
    Dave in Quad Cities, America
    Weil-McLain 680 with Riello 2-stage burner, December 2012. Firing rate=375MBH Low, 690MBH Hi.
    System = Early Dunham 2-pipe Vacuo-Vapor (inlet and outlet both at bottom of radiators) Traps are Dunham #2 rebuilt w. Barnes-Jones Cage Units, Dunham-Bush 1E, Mepco 1E, and Armstrong TS-2. All valves haveTunstall orifices sized at 8 oz.
    Current connected load EDR= 1,259 sq ft, Original system EDR = 2,100 sq ft Vaporstat, 13 oz cutout, 4 oz cutin - Temp. control Tekmar 279.
    http://grandviewdavenport.com
  • crash2009
    crash2009 Member Posts: 1,484
    Morning Dave

    I had you pegged as a micrometer kinda guy.  I was using all three hands yesterday.  Had to get 25 door closers working.  Spring loaded hinge pins, historicly correct, but a pain in the neck.
  • jpf321
    jpf321 Member Posts: 1,568
    buy a pocket rocket available from this site...

    it handles this task perfectly... http://is.gd/34cp65
    1-pipe Homeowner - Queens, NYC

    NEW: SlantFin Intrepid TR-30 + Tankless + Riello 40-F5 @ 0.85gph | OLD: Fitzgibbons 402 boiler + Beckett "SR" Oil Gun @ 1.75gph

    installed: 0-20oz/si gauge | vaporstat | hour-meter | gortons on all rads | 1pc G#2 + 1pc G#1 on each of 2 mains

    Connected EDR load: 371 sf venting load: 2.95cfm vent capacity: 4.62cfm
    my NEW system pics | my OLD system pics
  • Dave in QCA
    Dave in QCA Member Posts: 1,788
    make do in a pinch

    Micrometer.... no, just 2 sticks!  I woulda measured the circumferance, but didn't have the table handy.  My old rule of thumb, is the actual outside diameter will measure approximately the same as the next larger pipe size.   If it measures 5, it is 4".  measure 3, it is 2 1/2, etc.
    Dave in Quad Cities, America
    Weil-McLain 680 with Riello 2-stage burner, December 2012. Firing rate=375MBH Low, 690MBH Hi.
    System = Early Dunham 2-pipe Vacuo-Vapor (inlet and outlet both at bottom of radiators) Traps are Dunham #2 rebuilt w. Barnes-Jones Cage Units, Dunham-Bush 1E, Mepco 1E, and Armstrong TS-2. All valves haveTunstall orifices sized at 8 oz.
    Current connected load EDR= 1,259 sq ft, Original system EDR = 2,100 sq ft Vaporstat, 13 oz cutout, 4 oz cutin - Temp. control Tekmar 279.
    http://grandviewdavenport.com
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