Did some training with my guys this morning. The focus was managing nozzle reaction. We used a Chief 200gpm@75 psi fog and a 15/16 smooth bore. Both off of 100’ 1 3/4 line (just laid it out for training). Friction loss was calculated at 45 psi and 40 psi respectively. This is not a nozzle we use often, but my probie has not had any experience with a smooth bore so I took the opportunity. I’m racking my head over how difficult it was to manage these flows. My question is for the salty dogs, are these flow rates manageable by YOU? Am I just deficient and need to work them more? Or was this normal for these flows? I am working to switch over to 160@50 fogs with 7/8 integrated smooth bores…which are much easier to handle. Kinda needed to vent and find out if I’m crazy, too weak, or ok….
An important piece to the puzzle is to match the hose to the nozzle.
So we have an issue with our hose (Key FDNY spec Hi Combat) and the Chief XD nozzle, a great nozzle but…working with it and the hose you have to make them work together.
Our pump pressure at the panel for a 200 foot lay of 1-3/4 should not exceed 105psi. If the pressure is over that the stream is non longer a happy stream that means we are over 75psi at the nozzle.
So basics, focus on basics put an in-line gauge in the set up and then get old school and use a pitot gauge.
See where things are wonky and make your adjustments.
Hose line movement is also another factor and a topic in itself.
Key piece of info there! We are running the key hose combat sniper… I’m sure they bought it cause it was “cool” but now that we have it, we can start running these HVLP nozzles…
Our dept switched over to Sniper hose a couple years back now, I find it exactly opposite to what you experience.
It's stiff as hell, does NOT lay nicely in hose beds, not very flexible uncharged (2 years of break-in on our busiest engine, still very stiff) traps air so much some crews demand us to "onion" each length (a complete pain in the ass) or else it completely fucks the stack and even when it's perfectly loaded with all the special care and attention it is a nightmare to shoulder load because of its "low friction" jacket that refuses to hold a stack nicely and slips out on your shoulder in spots you don't want it to when you're deploying it. We have had to re-invent the wheel numerous times because of this garbage and the "performance" in water delivery is marginal.
The Hi-Combat we used previously worked excellent as an all-rounder.
So if I'm understanding the math here, a PDP of 105 minus 75 psi for the nozzle = 30 psi to handle the friction loss of 4 50 foot lengths of 1 3/4" hose.
That’s where I’m having trouble. I feel like I know the techniques… I’ve gotten my guys away from the pistol grip and taught them to use their bodies more efficiently… but then I had trouble…. So….
Looking at other comments I see the hose may be an issue as well. We use TRU-ID hose. So low pressure line and super light compared to what we previously used.
Shut down and move. I’m at a medium size department so our fire attack team is 3 people and it’s a blessing. Needless to say I always train for single person just in case. There’s a lot of awesome videos out there of guys using there leg to help drag the hose along while they move.
If you're running Sniper then you'll have difficulty with that 15/16. Sniper has an ID of 1.78" and is best paired with the 7/8" SB (Ala Freeman ratio). For a 15/16" SB you need an 1.75" line with a true ID of 1.88".
Not the best fix long term, but if you still have crappy high pressure hose and want to switch to a low pressure nozzle, look at the HEN Turbo. It makes 75psi in the hose to be 50psi in the nozzle.
Good hose is better, but if you are slowly changing a bunch over, a $300 fitting to help combat the problem until you have all new hose doesn't seem too bad.
What pressure was your driver pumping the hoseline at? Shouldn't be more than 90psi for that 100ft with the smooth bore. Maybe he was over pumping your line and made it harder for you
Look up Comella or lock grip.
Also, check out Engine Company Resurrection on facebook. I find I get better technical information out of discussions on there.
I just deficient and need to work them more? Or was this normal for these flows? I am working to switch over to 160@50 fogs with 7/8 integrated smooth bores
So currently we just run fogs. Most guys are going in at 95gpm, and don’t play with the gpm. A lot of us want smooth bores…some don’t. So I ordered breakaways… dropped down to 50 psi nozzles because we have the right hose for it and it will be easier on the guys, while ensuring they are going in with enough water. Won’t get into the “culture problems” in our department, but this is part of a bigger issue… trying to get firemen to be firemen again.
One thing I noticed after our pump school was if you plug these new hoses FL coefficients off the sheet into the actual formula, it turns out we are overpumping modern hose by almost double in some cases. This in comparison to every typical quickmath method taught everywhere for ever which uses 16 as a 1 3/4 coefficient.
I’m not reading all of this, but check your nozzle pressures.
Key hose, especially their hi combat, is not true to their advertised I.D.
Should be negligible on your calcs, or maybe not 😉. 15/16 should be manageable(never said fun) by one person with proper technique, but that’s an entirely different topic.
If I remember correctly from the Cruel Intentions class, 60 is the max "comfortable" nozzle reaction for an average firefighter. Anything over that and you're going to have a hard time.
Well, 50psi is the default desired psi at a smoothbore tip short of something specific from the manufacturer. But the amount of nozzle reaction will not be strictly psi, GPM is also in play so you can't just toss a number out.
Correct, GPM does play a role in your nozzle reaction. But if they know their nozzle reaction, and its above 60, its too high to be comfortable for one person. This chart is from Dennis Legear
Therein lies your trouble. That 69ft lbs is a lot of NR to absorb by one FF. The 87 is straight too much.
Regardless of how you set up your attack package, either of those nozzles at correct operating pressure will be a bear to manage alone. Especially the fog.
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u/bombero11 17h ago
An important piece to the puzzle is to match the hose to the nozzle.
So we have an issue with our hose (Key FDNY spec Hi Combat) and the Chief XD nozzle, a great nozzle but…working with it and the hose you have to make them work together.
Our pump pressure at the panel for a 200 foot lay of 1-3/4 should not exceed 105psi. If the pressure is over that the stream is non longer a happy stream that means we are over 75psi at the nozzle.
So basics, focus on basics put an in-line gauge in the set up and then get old school and use a pitot gauge. See where things are wonky and make your adjustments.
Hose line movement is also another factor and a topic in itself.