1. #1
    Firehouse.com Guest

    Post 2&1/2" vs 3" hose

    Any of you have a good source of any studies of this? I had a fire mag with a good article but can't find it.

    What are your pro's and con's for one vs. the other? Safety? Weight? Firefighting?


  2. #2
    Firehouse.com Guest


    For starters they have totally different functions on the fireground:

    The 2 1/2 inch is an attack line; whereas the 3 inch is a supply line.

    The 3 inch has roughly half the friction loss of the 2 1/2 inch, etc, etc.

    Stay safe!!

  3. #3
    Firehouse.com Guest


    What will you be using these lines for.
    3" can be used for attack, but it is much harder to move than 2.5"
    If you want to hit the fire then mop up with 1.75 then 3" will be fine.
    If your intent is to take the line inside then stay away from 3" it's too big and heavy. We have had several successful attacks with 2.5" inside buildings. Depending on your needs you may want to look into 2" line.

    As for supply line 2.5 red lines at 400
    3" red lines at 600
    if you can go even bigger to 4 or 5"

    Hope that helped

  4. #4
    Firehouse.com Guest


    I agree that a 3" line is too much to handle for interior attack. They are pretty demanding for exterior as well. The 2 1/2" is much easier to handle all around.

    As for supply lines, LDH is the proven way to go. However, if you are not in a position to change to a LDH, 3" is bigger than 2 1/2". On a department I used to be on, we had a 2 1/2" preconnect attack line on the engine. The hose load for supply was a dual 3" lay with 2 1/2" connections. We did a lot of testing and were amazed at how much more friction developed in the 2 1/2" lines when used for supply compared to the 3" even with the 2 1/2" couplings.

    Richard Nester
    Orrville (OH) Fire Dept.

    [This message has been edited by MetalMedic (edited August 02, 2000).]

  5. #5
    Firehouse.com Guest


    3" as a supply line (dual lay of course) has its advantages. You can flow almost as much water with dual 3" as with one 5". The advantage is if you lose one for whatever reason you still have a supply, as opposed to if you lose your one 5".

    My current department only carries three size lines: 5", 3", 2". 2" offers all the disadvantages of 2 1/2, without the flow capacity. 3" as an interior attack line is almost out of the question, however it is useful for master stream appliances and on handlines for "surround and drown" operations.

  6. #6
    Nick SBFD 6
    Firehouse.com Guest


    About two years ago, our department recived a whole S@#$ load of 3" hose from an area full time department. It is fairly new and we replaced all of our 2 1/2" hos ewith this new stuff. It has worked out great, it is mainly used for master streams. There is no real noticable difference in hadling characteristics Charged or Not between the two that I can see.

  7. #7
    S. Cook
    Firehouse.com Guest


    Depends on the application. Probably not a good interior line, but great for outside firefighting.

    The 3" makes a great blitz line with a Big Paulie nozzle, giving over 600 gpm. A 2.5" drops it to around 400gpm.

    I expect it will work well with TFT's new BlitzFire monitor too.

    In supply, a single 5" flows over TWICE as much water as dual 3" lines...

    At 25 psi hydrant.

    1 - 3" will move 222gpm 500' and 157gpm 1,000'
    2 - 3" will move 484gpm 500' and 343gpm 1,000'
    1 - 5" will move 1,108gpm 500' and 783gpm 1,000'

    At 50 psi hydrant.

    1 - 3" will move 342gpm 500' and 222gpm 1,000'
    2 - 3" will move 687gpm 500' and 485gpm 1,000'
    and 1 - 5" will move 1,567gpm 500' and 1,110gpm 1,000'

    At 80 psi hydrant.

    1 - 3" will move 434gpm 500' and 281gpm 1,000'
    2 - 3" will move 868gpm 500' and 562gpm 1,000'
    1 - 5" will move 1,982gpm 500' and 1,401gpm 1,000'

    Check out Paul Shapiros book "Layin' the Big Lines" for more info.

  8. #8
    Firehouse.com Guest


    I failed to mention in my 1st post that we already use 3" for blitz and supply but wanted to check out the 2.5" for additional attack lines to replace some of the 3"

    Thanks again for the help!

  9. #9
    S. Cook
    Firehouse.com Guest


    Are you researching this for the airport or for something else?

    [This message has been edited by S. Cook (edited August 03, 2000).]

  10. #10
    M G
    Firehouse.com Guest


    ....another person who swears that dual 3" hose is the way to go....UGH! This is kinda like the fire instructor who tells his students that if you are in a rural area that you should buy 4" hose instead of 5" hose because it takes less water to fill it...when will people stop being archaic and embrace ideas which work without thinking of and supporting the mindless arguments against it.

    Anyway, if you use 2.5 or 3" hose as attack/blitz lines, remember that the limiting factor is the nozzle. On one engine where I ride we have a 200' 3" preconnect with a 250 GPM nozzle, thats just silly! We could be using 1 3/4" hose in its place with the right nozzle. Go with the TFT Handline series nozzle (50-350 GPM) or smooth bore stacked tips on these lines to make the most of them (the big Paulie is simply stacked tips with a modified handle design and full flow 2" ball valve). The tailboard mounted deck gun would be well suited for 3" hose. I suppose that some folks would say that 2" hose pumped at higher pressures would do the same job...and, yes i'm sure it would. These are just some options you have.

    The information presented herin is simply my opinion and does not represent the opinion or view of my employer(s) or any department/agency to which I belong.

  11. #11
    Bob Snyder
    Firehouse.com Guest


    Lots of good points...no argument from me. I'll just interject this because there are some folks out there who tend to think in terms of friction loss vs flows:

    The friction loss in 2 1/2 lines is just a hair shy of triple the friction loss in 3" lines. Even for long attack lines, that would make a difference. Although, I honestly can't imagine anyone actually wanting to lug a 3" attack line around. Did it once in a training experiment. Won't do it again, if I can help it.

  12. #12
    Firehouse.com Guest


    On a long attack lay you can use 3 in. and y to 1 3/4 's for the last 50 to 100 ft.


  13. #13
    Jay Sonnenfeld
    Firehouse.com Guest


    I agree that 3" hose should not be used for hand lines. Its way to heavy and awkward. With today's manpower shortages its just not feasible. Take a 2.5 Blitz line with stackable tips (1.125 & 1.250 ) gives you 265 GPM and 325 GPM at 50 psi NP. This is still a good workout. Like someone said in previous reply lay 3" to gated wye and work from there . This also gives you the opportunity to swicth over to master stream if things get out of control.

  14. #14
    Firehouse.com Guest


    I find it hard to believe that we are having this discussion in 2000 about 3" or 2 1/2" supply hose. I'm not quite sure where some of you get your information( dual 3" hose flows as much as 5"). Oh, just like someone from a neighboring company once told me "you guys only have 5" we have 6" with dual 3's. Sorry, time to find a new hobby...wrong!!! Bying LDH is probably the smartest thing any company can do.

  15. #15
    Firehouse.com Guest


    I think 3" is a supply line, and 2 1/2" is a hand line. I calculated that each section of 3" holds about 6 or 7 gallons more water than a 2 1/2". That is about 50 lbs per section. It adds up when 200 feet of line needs to be moved for example. I also can get a better grip to pull the 2 1/2. The smaller diameter allows me to get a better hand hold and pull or handle the line. Sounds crazy, but if you have both, try it. When we went to 5" supply line years back, we of course had to keep the 3" on the engine also. My argument was that the 5" replaced the 3", and we should use 2 1/2" for large caliber hand lines. Some guys say we don't use large hand lines that often, so 3" will do the job. These guys think 3" is too much hassle to handle, so lets just flow 1 3/4" on everything! I think there is a time and place for duce and a half.

  16. #16
    Capt. LaFrance
    Firehouse.com Guest

    Thumbs up

    "Big Paulie" says: Big Fire=Big Water. Most of the time we use 1-3/4" attack lines with TFT 50-350gpm nozzles. If you are using a "blitz line it should be used for a blitz attack".We use 150' of Neidner 3' with a hydrant gate valve for a shut-off (no snapping the bail shut) coupled to a TFT MR nozzle. It can be deployed quicker than a step gun, and can be safely put in service by 2 firefighters. Agreed, it is not a line that has mobility, however if "Big Water" (600-800gpm) is needed, it foots the bill. When first introducted to this tool, I also was skeptical. But if you train, do the hydraulics, and use it safely, it is a great tool in the arsenal.

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