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Thread: Low Pressure Nozzles

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    Default Low Pressure Nozzles

    My department is looking into purchasing Low pressure nozzles. I've done a lot of research on the topic and by no means want to start the smoothbore vs fog nozzle debate. I've read the fire streams management handbook and enjoy any article written by the later Andrew Fredericks. I believe there is a right time and place for both, but as in most departments there is a vocal few who refuse to change for any reason. Currently we operate with all 100psi fog nozzles on our 1 3/4 lines set at 95GPM and have our PDP preset at 90 psi. Please, I don't need the math about how screwed up that is, this is the hole reason for looking into LP nozzles. I believe we need a minimum of 150GPM, but without blowing their minds with high PDP and NP. I want to keep the reaction forces between 60 & 70 for our outside station who operate with 2 on the line. I was told the reason we've always pumped so low is for line maneuverability, we run 4 on our central station engine and 3 on our outside engines. I'm a 15 year veteran and until now was not in a position to change this. I would like to set the engine up so that the officer has options based on conditions and personal preference, smoothbore and fog nozzles.
    I understand the break-apart nozzle concept, but honestly don't believe anyone will unscrew the fog head to use it as a smooth bore in a fire. I'm not apposed to break-aparts for the ability to clear the line of debris, I just don't want to really on them as our smoothbores.
    OK, enough of that! My main question is what brand and more importantly what GPM/PSI LP nozzles do you recommend and if a break-apart, what slug tip size and why? There are so many options to choose from. There is 150/50, 150/75, 175/75, 200/50, 200/75 and 7/8,15/16 and 1" slug tips.I plan on doing some comprehensive testing with several different nozzles using a flow meter and pressure gauge, but my OCD requires me to inquire prior to my own tests.
    Like I said before, I want to keep reaction force around 60 and have a nice tight straight stream with good distance and a GPM between 150-180. If you know of an LP nozzle set-up that will give me that, I would greatly appreciate the info (please don't say a smoothbore). Thank you and stay safe.

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    LP nozzles are definitely the way to go. That being said, one caution about break-apart nozzles: They provide the smoothbore option at a price to the functionality of the combination nozzle. Because you're supplying your combination tip through the smoothbore, you inherit limitations inherent to it.

    * You can't effectively throttle the stream; just on or off.
    * You can't have an effective constant pressure variable gpm stream; just the fixed gpm matched to the smoothbore.

    If you want to operate a smoothbore, put one on the end of the hose. If you want to use a combination nozzle, put on one of those. Avoid trying to do both at once with a break-apart smoothbore with a combi tip.
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    DM, can you explain your statements on limitations of the break apart nozzles? On or off? Why, you still have full use of the bale so I don't see why you would only have on or off.

    Lorain Fire, We Akron break apart nozzles. 200' 1 3/4" crosslays, 175/75 nozzles. Smooth slug is 7/8". With our hose, PDP is about 120 and gpm is 160 with the fog tip on, 170 with the fog tip off. Line is easily handled with 2 guys. Now people will go and through formulas and calculations stating this is not possible...but we used a flow meter and pitot to see what our numbers are....not math. Works for us.

    As for whether guys will/won't remove the fog tip for the smoothbore....it does happen. Some guys swear by smoothbore, some swear by adjustable tip. They both have the option. We've been running these for about 10 years now and don't see any reason to switch them out.
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    I don't really think it will matter much between the major brands of nozzles (Akron, Elkhart, etc.). What you CAN do to demonstrat the need for better flow is to show what the GPM requirements are for the buildings in your area. I think your fellow firefighters would be surprised how many gpm's a standard house fire requires.
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    Quote Originally Posted by Bones42 View Post
    DM, can you explain your statements on limitations of the break apart nozzles? On or off? Why, you still have full use of the bale so I don't see why you would only have on or off.
    Smoothbores are very sensitive to turbulence; that's why you always see them with a ball valve which is intended to be either fully opened or fully closed. You can operate then with the bail half-open but you get a very poor stream.

    Combination nozzles, OTOH, can be had with valves designed to minimize turbulence coming into the tip such as done by TfT with their slide valve.

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    The fundamentally different way that combination nozzles work allows them to have options that smoothbores cannot reproduce: throttling and constant pressure.
    "Nemo Plus Voluptatis Quam Nos Habant"

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    But that is an automatic nozzle, not a plain adjustable nozzle. I can guarantee you that my Akron's don't have all that spring loaded stuff.

    I will agree with you, automatics are a different breed and would cause an issue with a smoothbore tip.
    "This thread is being closed as it is off-topic and not related to the fire industry." - Isn't that what the Off Duty forum was for?

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    Quote Originally Posted by Bones42 View Post
    I will agree with you, automatics are a different breed and would cause an issue with a smoothbore tip.
    Correct. That's the issue I wanted to point out: If you use a breakaway, you're limiting yourself to a fixed gallonage combi tip without the option of delivering variable gallonage effectively either by throttling or varying supply pressure. IOW, removing a couple of the advantages associated with combi tips from consideration.
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    The OP was not asking about automatics. He was asking about adjustable nozzles. Two very different beasts.

    There is no issue at all with gating back an adjustable nozzle when/if less gpm is wanted. There is no limit to operating that way.

    There is an issue with gating back an automatic.
    "This thread is being closed as it is off-topic and not related to the fire industry." - Isn't that what the Off Duty forum was for?

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    Quote Originally Posted by Bones42 View Post
    The OP was not asking about automatics. He was asking about adjustable nozzles. Two very different beasts.
    I beg to differ, All automatic nozzles are adjustable nozzles; some adjustable nozzles are automatic nozzles. But, what matters is that we're clear on which nozzles we're talking about. With breakaways, you get a fixed gallonage smoothbore plus a fixed gallonage combination tip with very limited range of design flow.

    There is no issue at all with gating back an adjustable nozzle when/if less gpm is wanted. There is no limit to operating that way.
    Again, I beg to differ. You can throttle back a (manual) adjustable nozzle and get less gpm, but the nozzle is not designed to work that way unless you're dialing back the gallonage on the fly. Otherwise the stream will suffer due to turbulence and the mismatch between flow and orifice size.

    There is an issue with gating back an automatic.
    There is less of an issue throttling back an automatic (adjustable) because it will maintain proper tip pressure to compensate for reduced flow but will still suffer from turbulence -- unless it's a nozzle with a valve specially designed for that purpose instead of a ball valve.
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    I can't quote you any numbers, as I'm not familiar with your district. YOUR best option, flow-wise, is something only you can determine. That said:

    I'm a proponent of low pressure nozzles- for many reasons, including all those listed as reasons for the current SOP's. I'm also a proponent of giving the co's and front line troops options- I just hate a one size fits all solution- because it almost never does. As has been said before, the gpm flow must exceed that required by THIS fire. Limiting yourself to one rather low flow for offensive interior firefighting is dangerous.

    Elkhart Chiefs and Akron Assaults are both very popular low pressure/constant flow options. I have no experience with the Akron, but have used the Elkhart. It's simple, robust, and fairly firefighter proof. Changing flow settings is a simple matter of swapping out the stem and stream deflector for a different one. Obviously, you won't be doing that at a fire, but it's a far easier and less expensive method than buying entirely new nozzles. They're very lightweight, too.

    I'm also from a dept that loves their TFT's. In fact, everyone around here pretty much uses them. They do work quite well, but they do have their challenges. As a 100 psi auto, getting the most out of them requires a lot of pressure- translating into a STIFF nozzle reaction at higher (and more effective) flows. With the reality of severe manpower issues being the norm, anything we can do to make our lives easier is great.

    One advantage of a low pressure nozzle is simplification of pump ops if you also use smoothbores. If they all use the same NP, it makes the pump op's life much simpler. Meaning less chances of high pressure knobs being way under pumped, while the team with the smoothbore is hanging on for dear life.

    Check out Fyredup's posts for some good examples. They use the Elkhart Chief low pressure, and
    also use the breakapart concept to good effect. I spent a good deal of time reading them, as I was looking into the same thing. If you prefer one or the other, simply use 1 shutoff, with or w/o the slug tip, and finish some with combos and others with strait tips. Either way, the np is the same.

    I would recommend using a fairly large slug tip if you go that route. This isn't really meant to be the primary smoothbore option. It's more of a big flow option when you need it. It also works great, if you're a CAFS user, for fluffy dry foam for exposure protection/pre treatment. A larger slug tip will give you more flow options for the combi or sb tips you can effectively use with it. It would make no sense to pair a 7/8" slug tip with a 200+ gpm combo tip, for example. A 1" or 1 1/8" would be better.

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    Good afternoon folks.

    My #1 POC FD has used sigle gallonage low pressure combination nozzles for over a decade now and I believe I can clear up some of the questions raised here.

    We do use Elkhart Chief combination nozzles rated at 200 gpm at 75 psi. They are attached to a pistol grip shut off with a built in 1 1/4 inch slug tip. This set-up is used on 2 inch hose. We initially underpump the combo tip to 55 psi nozzle pressure for a flow around 160 gpm. This makes a good looking stream with adequate reach and is easily handled by 1 guy at the nozzle. We can of course bump up to 200 gpm at 75 if need be, or remove the combo tip and go right to the slug tip and flow 300 gpm at 42 psi nozzle pressure.

    I have to disagree with the comment that you can't gate this back to flow less water if you find like a trash can or a smoldering over stuffed chair. I have done it many times and had no issues at all.

    I think some definitions are in order:

    Solid stream: a fire stream produced from a fixed orifice, smooth bore nozzle

    Constant flow nozzles: designed to flow a specific amount of water at a specific nozzle pressure, this nozzle pressure may be 100, 75, or 50 psi

    Manually adjustable nozzles: a refinement of the constant flow nozzle that has a number of constant flow settings adjustable by a ring on the barrel of the nozzle

    Automatic nozzles: a nozzle designed to attempt to maintain approximately the same nozzle pressure even if the amount of water supplied to the nozzle changes, this occurs through the use of a spring loaded baffle that adjusts to the water flow supplied to the nozzle
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    Quote Originally Posted by DeputyMarshal View Post
    I beg to differ, All automatic nozzles are adjustable nozzles; some adjustable nozzles are automatic nozzles. But, what matters is that we're clear on which nozzles we're talking about. With breakaways, you get a fixed gallonage smoothbore plus a fixed gallonage combination tip with very limited range of design flow.

    Technically true, but not the recognized definition of an adjustable nozzle. An adjustab;e nozzle has traditionally been one with a gpm selector ring.

    Your information on what type of nozzle tip you can put on the end of a slug tip however is wrong. Both TFT and Elkhart sell automatic nozzle tips for handlines without a shut off for attachment to whatever shut off you want. In fact TFT sells ball valve shut offs for attachment to their line of automatic nozzles.


    Again, I beg to differ. You can throttle back a (manual) adjustable nozzle and get less gpm, but the nozzle is not designed to work that way unless you're dialing back the gallonage on the fly. Otherwise the stream will suffer due to turbulence and the mismatch between flow and orifice size.

    Just like yout TFT will when attached to a TFT ball valve shut off...



    There is less of an issue throttling back an automatic (adjustable) because it will maintain proper tip pressure to compensate for reduced flow but will still suffer from turbulence -- unless it's a nozzle with a valve specially designed for that purpose instead of a ball valve.


    The biggest issue with gating back a TFT is you have absolutely no clue how much water you are flowing. I have taught in FDs where they use automatics and were set to flow 200 gpm with the engine pressure they set. Only to find guys were gating the nozzle and a quick check with a flow meter most often showed flows in the 100 gpm or less range.
    The truth is at most of our paygrades we have little input as to the nozzle selected. My advice know what yu have and make it work.
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    Like FyredUp, we also use the Elkhart break apart nozzles.

    Speedlay 1 is 200' 1 3/4" Ponn Conquest with a 175 @ 50 Chief combo tip with a 15/16" internal smooth bore shutoff.

    Speedlay 2 is 200' 1 3/4" Ponn Conquest with a 15/16" smooth bore tip, stream shaper and 1" internal smooth bore shutoff.

    Both lines are pumped to 120 PSI and achieve 175-180 GPM. This was varified with a flow meter on both of our front line engines.

    The utter simplicity of the setup is what drove me to implement it. We previously used automatic, fixed and selectable gallonage nozzles, all with different nozzle pressures. This made it basically impossible to teach a group of limited time volunteers friction loss and what we needed to pump at. We replaced everything with new nozzles and we are now the same across the board.

    I see little to no reason to have multiple flows for the same lines. We now know our firefighting target flow and pressure for every structure fire we go to. If 175 GPM isn't cutting it, we pull the 2 1/2" line and hit it with 250-260 GPM (also running fixed fogs and single tip smooth bores). If this still doesn't knock it down we go to the deck gun. Simple as that.

    Obviously once the fire is knocked down and we are in the mop up phase we can lower PDP, pull the booster, etc. But for initial attack our guys have one pressure and flow to remember for the 1 3/4" lines and one pressure and flow to remember for the 2 1/2" lines.

    If you are considering low pressure, high flow nozzles I would suggest upgrading to a premium attack hose as well. Low budget hose does not play well with low pump pressures and will kink like crazy. Not to mention you should be able to cut off even more pressure with better hose.

    I have yet to hear a good reason for still buying 100 PSI nozzles.
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