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  1. #1
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    Default 11/2 vs 13/4 hose for attack line

    We are currently using 1 3/4 atack lines. The department is looking at replaceing a large portion of our old hose. We are hearing of alot of departments going back to 1 1/2 hose for attack lines. What we are hearing is that with todays new nozzles, you are able to get about the same amount of water out of a 1 1/2 as what you would get out of a 1 3/4. We are looking at 1 1/2 for the ease of getting around in a building, and that it is eaiser for the guys to use since we have less manpower to begin with. Anybody have any thoughts or information on this?


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    Forum Member FyredUp's Avatar
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    Quote Originally Posted by rands1 View Post
    We are currently using 1 3/4 atack lines. The department is looking at replaceing a large portion of our old hose. We are hearing of alot of departments going back to 1 1/2 hose for attack lines. What we are hearing is that with todays new nozzles, you are able to get about the same amount of water out of a 1 1/2 as what you would get out of a 1 3/4. We are looking at 1 1/2 for the ease of getting around in a building, and that it is eaiser for the guys to use since we have less manpower to begin with. Anybody have any thoughts or information on this?
    Anyone telling you that you can get the same amount of water out of an 1 1/2 inch line as you can a 1 3/4 inch line is simply WRONG. Physics simply won't allow it. The nozzle, no matter what color, type, brand, or whatever, does not magically produce water. I have to beleive some less than scrupulous salesman is trying to unload both hose and nozzles he is stuck with.

    Seriously, why would you step backwards to 1 1/2 inch lines from 1 3/4 inch lines? Are you tired of being able to flow 200+ gpm with your small attack lines? Further if 2 guys can't handle a 1 3/4 inch line maybe it is time for a physical fitness program for your FD. On m career FD we regularly do things like car fires with one guy on the line and the other checking the car and opening up the hood.

    My volly FD uses 2 inch hose exclusively for handlines. We routinely operate that with 2 people on the line. We went to 2 inch hose because we too are shorthanded at times due to being primarily a bed room community. We use combo nozzles rated at 200 gpm at 75 psi with a 1 1/4 inch slug tip behind it that flows around 300 gpm at around 45 psi.

    My advice? Either stay with the 1 3/4 inch hose or get radical and move up to 2 inch hose. 2 inch hose in my mind is the perfect hose for short staffed FD's we flow down to 1 3/4 inch flows and up to 2 1/2 inch flows and never have to do anything more than spinoff the combo tip to make it happen.

    Of course it just ocurred to me if you are one of those FD's flowing 125 gpm through your 1 3/4 inch lines you could easily switch to 1 1/2 inchlines and see no difference in your fire attack. Well, as long as the engine operator knew he had to boost the engine pressure to overcome the additional friction loss in the smaller hose.
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  3. #3
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    Insanity.

    What's the real motivation for reducing the hoseline size?
    I am now a past chief and the views, opinions, and comments are mine and mine alone. I do not speak for any department or in any official capacity. Although, they would be smart to listen to me.

    "The last thing I want to do is hurt you. But it's still on the list."

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    I suppose you could but unsure exactly why. Just doing straight by the book calculations but making the assumption you are using a 15/16" smoothbore nozzle on a 200 foot preconnect with 1.5" hose you would need to pump at a tick under 215 psi. Math = Engine Pressure (EP) = CQ^2L + (50 psi NP)
    C=24 for 1.5" hose
    Q=1.85 for 185 gallons per minute on 15/16" smoothbore
    L=2 for 200 feet of hose
    EP = (24 * 3.4225 * 2) + 50 = 164.28 + 50 = 214.28 psi

    If you changed nozzles to a 150 gpm @ 75 psi fog with 200 feet of hose the by the book calculations you would get the following 1.5^2 = 2.25 for Q^2
    EP = (24 * 2.25 * 2) + 75 = 108 + 75 = 183 psi

    Therefore, theoretically you can achieve decent flows through a 1.5" hose but you would need to compensate by bringing your engine pressures up higher. These numbers are solely by calculation you would have to test your hose and truck to confirm or deny but the book calculations in the past have been close in my experience usually less than 5% error. My personal opinion would not be to switch back. I don't believe you gain enough in mobility for what you lose in flow capability. Our current setup is either a the 150 @ 75 psi combination or a 200gpm@75 psi combination nozzle. With the 200 gpm nozzles with 200 feet of 1.75" hose we can pump at 130 psi and get 150gpm, 150 psi and 170 gpm, and 200 psi and 200 gpm. These are flows for interior handlines for us. We do not want to be below the 150 gpm inside for a fire.

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    Forum Member len1582's Avatar
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    If the boys can't handle a 13/4" what makes you think they can handle a 11/2" ?? We have about 80psi at the nozzle and get about 175-180gpm. We use more rule of thumb than exact calculations. Maybe you need a better nozzle. Or tell the guys it's not a garden hose...grow a pair and deal with it. Good luck.

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    The nozzle's are another area that we are looking at. As far as we can tell our newest nozzle is about 15- 17 years old. From what I can tell from inspecting them is that almost every nozzle that we have needs some kind of repair.

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    Forum Member FyredUp's Avatar
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    Quote Originally Posted by rands1 View Post
    The nozzle's are another area that we are looking at. As far as we can tell our newest nozzle is about 15- 17 years old. From what I can tell from inspecting them is that almost every nozzle that we have needs some kind of repair.
    Don't fall for the hype of overpriced automatic nozzles. Figure out how much water you want to flow and buy a nozzle designed to flow that amount. If it is a 50 or 75 psi low pressure combo all the better, although a smoothbore would be my first choice.

    The biggest problem with automatic nozzles is the complete lack of maintenance. If you read the instructions that come with the TFT line they call for periodic maintenance. As an instructor I ask when was maintenance done last and most often I hear "What Maintenance?" I have had automatics used in class not operate properly because of that lack of maintenance. Isd that the nozzles fault? Nope. But a single gallonage nozzle doesn't have the issues an automatic does.

    What ever you do test nozzles before you buy. Borrow them from vendors and test them without the salespeople being there.
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    If your guys are having a hard time with a 1 3/4. i think that training might be the issue and not the hose. Either the handlines are being over pumped, or the nozzleman is not holding the hose the right way.

    As far as nozzles i like simple smooth bore and constant gallonage fog nozzles. less stuff to break and keep up with.

    I would determine what your department wants for a target flow from medium calliber handlines. I.E. 125,150,200,etc. GPM. This would take into acount various things such as manpower, typical tactics, building construction, response times, etc. Then design your hose lay to fit that target flow. use the nozzle pressure reguired, target GPM flow, Friction loss for that target flow. Use that info to determine the PDP for the hose size and select the best hose size for your department.

  9. #9
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    Think of this.

    There will be fires that require your low staffed dept to pull a 2 1/2. But due to a lack of manpower all that you can put into service and be mobile with is a single small caliber line. At this time you will want maximum performance from that small line with limited manpower. An 1 1/2 line won't cut it. If all you think of is small fires, you will be screwed when the big ones come.

    Maximize the potential of your limited manpower.
    We do not rise to the occasion. We fall back to our level of training.

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    sorry but lack of man power is no reason to not pull a 2 1/2. the fire dictates what hose line we pull. BTU's=GPM. Sure man power will factor into how we will use the hose line. As in offensive or defensive tactics. However two people can advance a 2 1/2 hose line offensively into a structure. Is it going to be tougher then a 1 3/4? yes, but it is not that bad. Dont be afriad of the 2 1/2. it is a tool just like anything else on your engine.

  11. #11
    Forum Member FyredUp's Avatar
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    Quote Originally Posted by RFD21C View Post
    sorry but lack of man power is no reason to not pull a 2 1/2. the fire dictates what hose line we pull. BTU's=GPM. Sure man power will factor into how we will use the hose line. As in offensive or defensive tactics. However two people can advance a 2 1/2 hose line offensively into a structure. Is it going to be tougher then a 1 3/4? yes, but it is not that bad. Dont be afriad of the 2 1/2. it is a tool just like anything else on your engine.


    I would add not to be afraid of the 2 inch line. To me it is the best compromise for understaffed fire departments. It can be underpumped to flow 1 3/4inch flows and pumped to flow 300 gpm like a 2 1/2. We move it with 2 people on the line.
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    Like stated above stay with 1.75 and don't be afraid of 2.5 if you train with them then you will see that they are not that bad. I have flowed 350gpm on the nozzle standing up by myself. They are not the monster that some make them out to be.

  13. #13
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    Default Flawed Logic

    Quote Originally Posted by rands1 View Post
    We are looking at 1 1/2 for the ease of getting around in a building, and that it is eaiser for the guys to use since we have less manpower to begin with. Anybody have any thoughts or information on this?
    Clearly there plenty of good post here already. There are major holes in the logic to downsize. One not mentioned (maybe?) is that to even come close to flowing the max from your 1.5" the line will be like pipe- nearly unbendable. And like any hose, add in two 90 turns and it's an anchor line unless you have personnel in the right positions to facilitate the stretch.

    The logic that nozzle now will allow the hose to flow more is flat out wrong. Diameter is diameter. Using the same theory, the 1.75" could flow even more than it did before? Hence, the smaller line will never "catch up" in gpm.

    An 1.75" line can be very manageable with proper nozzles and training, with the added bonus of more BTU killing power. GPM is what wins the fight, so as has been stated previously, pull the line with the proper flow the first time.

  14. #14
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    Quote Originally Posted by Itshotinhere View Post
    Like stated above stay with 1.75 and don't be afraid of 2.5 if you train with them then you will see that they are not that bad. I have flowed 350gpm on the nozzle standing up by myself. They are not the monster that some make them out to be.
    I've said it before and I'll say it again here.

    For almost every single family dwelling, a 2.5 is more work then it's worth.

    It's not the nozzle reaction, it's getting it to make bends.
    I am now a past chief and the views, opinions, and comments are mine and mine alone. I do not speak for any department or in any official capacity. Although, they would be smart to listen to me.

    "The last thing I want to do is hurt you. But it's still on the list."

    "When tempted to fight fire with fire, remember that the Fire Department usually uses water."

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    Quote Originally Posted by RFD21C View Post
    sorry but lack of man power is no reason to not pull a 2 1/2. the fire dictates what hose line we pull. BTU's=GPM. Sure man power will factor into how we will use the hose line. As in offensive or defensive tactics. However two people can advance a 2 1/2 hose line offensively into a structure. Is it going to be tougher then a 1 3/4? yes, but it is not that bad. Dont be afriad of the 2 1/2. it is a tool just like anything else on your engine.
    One step at a time. They claim not to have the manpower for a 1 3/4. Let's get em used to the 1 3/4, then work on the 2 1/2.
    We do not rise to the occasion. We fall back to our level of training.

  16. #16
    Forum Member FyredUp's Avatar
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    One person can bring a dry 2 1/2 to the door, get the line charged and do a hard hit while the rest of the crew is stretching a 1 3/4 inch line.

    The folly that every time a 2 1/2 is pulled we are dragging it all over the place is one of the reasons hard hits aren't made often enough to kill big fire quickly.
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  17. #17
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    Quote Originally Posted by FyredUp View Post
    One person can bring a dry 2 1/2 to the door, get the line charged and do a hard hit while the rest of the crew is stretching a 1 3/4 inch line.

    The folly that every time a 2 1/2 is pulled we are dragging it all over the place is one of the reasons hard hits aren't made often enough to kill big fire quickly.
    We call it a blitz attack and all our engines have a dedicated 2 1/2 crosslay for that purpose.

    However, it's rarely (never?) pulled for an interior attack.
    I am now a past chief and the views, opinions, and comments are mine and mine alone. I do not speak for any department or in any official capacity. Although, they would be smart to listen to me.

    "The last thing I want to do is hurt you. But it's still on the list."

    "When tempted to fight fire with fire, remember that the Fire Department usually uses water."

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    Quote Originally Posted by rands1 View Post
    We are currently using 1 3/4 atack lines. The department is looking at replaceing a large portion of our old hose. We are hearing of alot of departments going back to 1 1/2 hose for attack lines. What we are hearing is that with todays new nozzles, you are able to get about the same amount of water out of a 1 1/2 as what you would get out of a 1 3/4. We are looking at 1 1/2 for the ease of getting around in a building, and that it is eaiser for the guys to use since we have less manpower to begin with. Anybody have any thoughts or information on this?
    At my fire department, we have recently gone the other way. We went from 1 1/2 to 1 3/4. Me personally I like the 1 3/4, because to me its no difference between the 2. I have been by myself on both and have not felt a difference between them. Some people dont like the bigger hose, but I am one for it. A lot of our mutual aid departments still have 1 1/2 because they claim for less manpower, but we have the same amount of people show up just as they do and we get along just fine.

  19. #19
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    Pressure (Friction) Loss in PSI per 100" Hose


    GPM___1.50"____1.75"____2.00"_ __2.50"

    100.......25.........12....... ..6..........3
    125.......37.........21....... .10..........4
    150.......54.........26....... .14..........6
    200..................45....... .24.........10
    250..................70....... .38.........15
    300..................95....... .54.........21



    Nuff Said!
    HAVE PLAN.............WILL TRAVEL

  20. #20
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    As always, I can count on fellow forum members to provide good advice and tips. You have given me alot of information to keep our hose at 1 3/4. thank you so much. Now hopefully our fire millage passes this fall so that we can still have a fire department.

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