Thread: Nozzle

  1. #1
    chiefjay4
    Firehouse.com Guest

    Post Nozzle

    What size smoothbore nozzle on the 2 1/2"?

  2. #2
    Plug-Ugly
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    Post

    Standard fire stream = 2 1/2" hose, 1 1/8" tip, 45-50psi nozzle pressure, 250 GPM.


  3. #3
    BIG PAULIE
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    Post

    1" tip @ 100 psi np = 300 gpm
    1-1/8" tip @ 115" psi np = 400 gpm
    1-1/4" tip @ 80 psi np = 400 gpm
    1-3/8" tip @ 55 psi np = 400 gpm
    1-3/8" tip @ 80 psi np = 500 gpm
    Remember
    1.The waterway in the nozzle valve should be larger then the tip size.
    2. A stream shaper will improve the stream performance. This is a good to have but not mandatory.

  4. #4
    FyredUp
    Firehouse.com Guest

    Post

    1 1/4" at 50 psi gives you 326 gpm.

    We use this size tip on our 2 inch hose.

  5. #5
    Lt.Houck
    Firehouse.com Guest

    Question

    Big Pauli,

    I was wandering if you have ever actually used these pressures on those nozzle sizes? The normal operating pressure for solid bore nozzles in 45 to 55 psi at the nozzle. This pressure creates the best stream with the most reach and a reasonable amount of back pressure. To go along with your numbers I have calculated the Nozzle Reaction Force for those flows.

    1" tip at 100 psi np = 300 gpm & 157lbs rf
    1 1/8" at 115 psi np = 400 gpm & 228lbs rf
    1 1/4" at 80 psi np = 415 gpm & 192lbs rf
    1 3/8" at 55 psi np = 415 gpm & 163lbs rf
    1 3/8" at 80 psi np = 500 gpm & 237lbs rf

    Give the fact the a 1 3/4" attack line with a fog nozzle at 100 psi nozzle pressure and flowing 150 gpm has a reaction force of only 75 lbs, I think its safe to say that most of the numbers you posted are not safe. You can get 325 gpm from a 2 1/2" line with a 1 1/4" tip at 50 psi NP and only have 122 lbs of reaction force. Trying to force more water thru a solid tip nozzle rather than going up a size just leads to problems and a chance of someone getting hurt should that line get away from the nozzle person, especially with 237 lbs reaction force pushing it around.

    Chiefjay I would stay with no more than 1 1/4" tip anything more can be very hard to control.
    Good luck, and stay safe

  6. #6
    Dalmatian90
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    Post

    *chuckles* the Lt's never seen Big Paulie operate...

    Actually, at our Monday night drill before BP posted his above formulas, we had a 2.5" in operation with the 1-1/8" and 115psi on the tip. Handled nicely by two firefighters standing up, the backup man backed into the nozzle man...plus a third kneeling on the line a few feet behind them. So I've used them, but it's not unmanagable with a trained crew -- and we're not pulling out all of BP tricks.

    Now I do prefer to use a portable gun when flowing in the 350+ gpm range, but if you need to it's nice to know how to make the big flows from handlines.

    With our new ladder going in service, our 1st Due Engine-Tank will arrive with it's 2.5" preconnect w/fog nozzle, and the Ladder will keep it's 2.5" preconnect with a medium-sized playpipe & 1-1/8" at the end of the stacked tips.

  7. #7
    *LHS
    Firehouse.com Guest

    Post

    Wow, 125 pounds reaction on a 2 1/2" fog tip flowing 250 gpm at 100 psi nozzle pressure. SO if yo let go of the nozzle would the hose go flying off?

    Sounds like a bunch of useless book stuff to me. Keep your books I'll take street smarts any day. 125 pounds reaction yeah right!

    Why does the line fly away? Why can 1 guy flow 250 gpm all day? Look mom, no hands!

    go to and explain the photo
    http://www.geocities.com/Baja/Trails/6658/b.html




    [This message has been edited by *LHS (edited 06-19-2001).]

  8. #8
    Lt.Houck
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    Post

    I've seen your picture in the magazine article that it came from. If you notice the ff is not using a solid bore nozzle, nor is the nozzle set to straight stream. A Fog nozzle opened up on a wider pattern dramatically reduces the reaction force of the nozzle. The ff is also has the hose laid out in a perfectly straight line behind him for at least 25' to 50'. I have tried this technique and it uses the friction of the straight hose on the ground to keep the nozzle from slipping away.

    The only reason I asked about the over pressuring of the smaller tips, is because the same flow could be reached with less effort from the nozzle person simply by increasing size. I will have to give big paulie's numbers a try though to see how they work out.


  9. #9
    *LHS
    Firehouse.com Guest

    Post

    Actually, the original photos are mine.

    So the fog nozzle being in a wide fog is why the nozzle doesn't take off? Funy even with the hose in a tight half circle it doesn't take off.

    Ok, here it is in straight stream. Does anyone really believe there is 125 pounds reaction against the lap of the nozzleman? Book reaction numbers and reality are way off.
    http://www.geocities.com/ecburtblue33/f.html

    [This message has been edited by *LHS (edited 06-19-2001).]

  10. #10
    Lt.Houck
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    Post

    There are a lot of factors going into that nozzle staying where it is. The lap of the ff is not what is keeping the hose from moving. It is the friction of the hose on the ground. What happens when the ff turns the nozzle to one side or the other. As for reaction force, it is based on physics and is very accurate. When you loop the hose in a circle and sit on it you are again using friction and you body weight to stop the line from moving. Try those experiments on wet grass or other surfaces with less friction. Or simply try to have the ff move the line by himself. I agee with you that reaction force is easy to over come, with good tactics and training. I used that article to teach my own personel some of the techniques shown. They work very well. But as I said if you change some of the variables such as adding wet grass or a ff trying to direct the line to one side or another it gets much more difficult than the pictures would have you believe. I am not concerned with the stationary 2 1/2" line in defensive ops. I am worried about the crew working the line on the fire ground while trying to make an attack. I have seen handlines get away from people, I have seen ffs get hurt from this. Don't underestimate the force behind that nozzle.

  11. #11
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    LHS:
    I know you probably cant respond anymore but what the heck.

    /Book reaction numbers and reality are way off./

    If this is the case then why on earth would you use book numbers to support your position in articles you wrote in Firefighter News? Or, why no mention of this when some peoples reaction testing matched what a book said?

    Come on Larry, at least try to be consistent.
    Kirk Allen
    First Strike Technologies, Inc

  12. #12
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    Lt Houck, Mother earth can absorb alot more nozzle reaction then you think. These flows and pressures are meant to be used in the stationary non advancing mode to make a big hit on a big water volume fire.We always think of a large diameter handlie(2-1/2" or 3") as being a line that has to be advance while flowing. On exterior big hit attacks I don't think this is nessacary. Stop, make a hit, gated down and reposition for the next hit.I n alot of cases one hit can get the knockdown allowing for the smaller handlines to ADVANCE in to get the extinguishment.

  13. #13
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    I guess I forgot to say that when you stop to make the hit just have a seat. No loop is required. I have found that flows of 400 gpm and higher takes the body wieght of to firefighters. I have delivered 800 gpm through a 3" handline with to 180 pounders sitting on it. I like the 500 gpm lines best. It can be deployed from tank water and is fairly easy to sucure a water supply for.

  14. #14
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    two more cents. I think a 325 gpm handline using a 1-1/4" tip at 50 pounds NP with two firefighters standing up is more dangerous and harder to handle then a 500 gpm handline using a 1-3/8" tip at 80 psi NP with two guys sitting on it.

  15. #15
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    Paulie is right on with the stationary flow, shut down, advance, and hit again. This allows a nozzle team to make an aggressive attack with a 400 plus GPM line. We drill this method using 4 targets and 4 different nozzle locations. The team moves to location one, knocks over the target 1 , shuts down and moves to location 2 etc. It works great and trains the teams for actual fire attack with big water. We run this drill using 1 1/4 nozzle @ 80 np for 400 GPM

    Good Luck,

    Firehose

    [ 07-01-2001: Message edited by: Firehose ]

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    In answer to your question. Their is no benifet to using a bore size of greater than 1/2 the diameter of the hose. So 2.5 inch hose 1.250" bore. 1 3/4" hose 15/16" bore. You can go smaller but stream really takes a crap if you go bigger. Longer stream shapers help or just a longer nozzle. Remember the best nozzle is the one you have in your hand

  17. #17
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    Hey chief. get your boys to put the 1-1/8" tip on the 1-3/4" line and evaluate the stream. I had some of them in the Michiana class last month and we did it. They were impressed. I have seen the rule that you talk about but have never understood why it was. If the water is available from the hose size to support the tip of choice then it should make no difference whether or not the tip is larger then half the diameter of the hose. If a 1-1/8" tip is ok to use on a 2-1/2" at 250 gpm then why can't it be used on a 1-3/4" at 250 ?null

  18. #18
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    Paulie,

    We have not tried the 1 1/8 on the 1 3/4 but have tried it with the 2 inch. Works great and is much easier to move.

    Firehose

  19. #19
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    Paulie I guess I will have to go out and try that. Just thinking about it and I can't see why it wouldn't work. I was trying to remember, the rule has to do with velocity. I was thinking that the velocity had to do with keeping the stream tight and for reach? I guess I will have to go out and see.

  20. #20
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    The reason for the rule of thumb is, if the nozzle diameter is larger than one half the diameter of the hose, the hose will have a tendency to kink. If you increase the pressure at the nozzle to greater than what is intended, 50 psi for a handline, you will increase the nozzle reaction. More water, more mass, more nozzle reaction. Can it be done...sure. But that is why its a rule of thumb and not a physical law.

    [ 07-19-2001: Message edited by: amfm ]

    [ 07-19-2001: Message edited by: amfm ]

    [ 07-19-2001: Message edited by: amfm ]

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