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Exposure Hose Lays
Hello all, we are discussing options to allow faster deployment of exposure lines without crippling an engine by taking up a pre-connected line solely with an Akron Ozzie that was bought by the Chief. Does anyone have any SOG's for exposure lines? Does anyone have the same situation and a good solution? Any feedback will be greatly appreciated. Thank you all!!!
Casey
Casey
Replies to This Discussion
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Permalink Reply by Paul Montpetit on
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I have to agree 400' of 1 1/2...? Why not just give your guys a few beers and have them p_ss on the fire...? probably get as much wet stuff on the fire....sure you can put the pressure to it but pressure and volume are 2 separit things....Paul
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Permalink Reply by B.L.P.S. 13 on
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I am having a hard time understanding why you people can't do the simple math on this. These hand line nozzle are rated to flow 125 gpm at 100 psi. That's what they do, so why is this such a hard concept to grasp? Guessing if you can't get on board with the 400' 1 1/2, you probably won't understand how we run the 650'.
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Permalink Reply by FETC on
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I responded to another person from Maryland with the same theory / calculations about the 650' inch and half method you use as an example in another thread.
Can it be done as described, definately... can it be done other ways absolutely. I would like to point out though, that if you want to actually operate that 650' 1-1/2" handline at the recommended pressures listed above, thats OK, pumps can handle it but you are also operating above the recommended 1962 hose testing rating.
Where's the safety? Not to mention I can flow different combinations that offer far less EP, FL and NF.
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Permalink Reply by Tony P on
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Jay, I'm not saying that a line used for exposure protection isn't a 'defensive' line - it is, it's for the defense of a non-involved structure. I'm disagreeing that to deploy an exposure line implies that the fire is lost. Do we deploy exposure lines often? No, rarely. Are we ready to deploy an exposure line? Yes, at every going fire - if the fire is coming out of the side of a house then we want to be ready to protect the structure next door. The uninvolved building is of more importance than the involved one - the involved structure is already badly damaged.
Do I agree with having a portable monitor pre-attached to a hoseline? No, I don't. I think that sort of equipment belongs in a locker (compartment to you) the way we keep ours.
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That's a fair assessment. However, the time, which is crucial in fire supression, it takes to place this into operation is unmatched by any other configuration. On top of that its manuverability beyond the initial attack, (redeploying to another floor), can not be surpassed by larger lines.
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So you are flowing 125gpm then....not 150gpm...just seems that if you ran either 2 1/2" or 3" (4 ") as a supply line and then used a siamese wye and your 1 1/2 attack line off that ...would be a little less FL involved. Hey whatever works for you......Paul
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Permalink Reply by Ben Waller on
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It doesn't matter how often you use the Ozzie. What matters is that you need to have hose bed design that allows for it to be preconnected and to be carried safely without compromising the preconnect beds that you use on a more frequent basis.
If your engine is designed with enough preconnect beds to preconnect the Ozzie and mount it secured to a tailboard or side step, then by all means, hook it up. If not, save the preconnects for handlines that will be used more frequently.
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1-1/2 lines longer than 300 feet have so much friction loss that using the longer lines is inefficient and puts unnecessary wear on the engine drive train and pump.
We can do the simple math, and that's why we know that long 1-1/2 lines are a poor choice compared to some of the other options out there. C(Q squared)L...simple math.
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If you're pumping a 1-1/2 at 300 PSI at fires then you're engaging in two less-than-desirable practices.
1) You're conducting an annual "max pressure" test on that line every time you pump it at that pressure. That puts unnecessary strain on the hose on a routine basis. Using larger-caliber leader lines at lower pressures is less damaging to the pump.
2) You're putting excessive stress on your engine's drive train and pump. Using lower pressures and leader lines with lower pressures is a much better practice.
Just because you can do something doesn't mean that you should do it.
Further, the fire isn't extinguished with pressure, it's extinguished with volume. If pressure extinghished fires, we'd be using compressed air as the extinguishing agent, not water.
As a point of comparison, my department uses 1-3/4 hose with 50 PSi nozzles that flow a max of 185 GPM and are just as easy to handle or move as 1-1/2. We move 150 GPM with a rule of thumb FL of 20 PSI per 100 feet...just as easy on the crew, safer for the hose/less risk of bursting a length, and much better for the pump and drive train.
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Permalink Reply by Jay Nicholson on
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Then I believe we are on the same page.
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Ok. Last time, pay attention. I never said anything about pumping at 300 psi. It's just a nominal figure that gives us a maximum pressure. On top of that, all the equations I posted earlier ate not calculating intake pressures, which ultimately lower the engine pressures anyway.
Your low pressure approach also make you very succeptible to kinks. The lower your pump pressures are, the easier it is to bend your hose. The easier it is to bend your hose, the less gpm you actually get at the tip.
And you can not make up your own coefficient for friction loss. 30 psi per hundred feet applies to 1 1/2" and 1 3/4". Don't try using smaller numbers to further your cause.
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200' of 1 1/2" we run Pump pressure of 145 for 125 gpm and for 150gpm we rum Pump pressure of 190.....actually put a flow meter on the tip to check these "rules of thumb" numbers......Paul
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