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Thread: 1 or 2 streams

  1. #1
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    Question 1 or 2 streams

    Ok, You figure that you need 250gpm flow to put out a garage fire. Is there a difference in 2 1 1/2 lines at 125gpm each, or one 2 1/2 at 250.


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    double post, sorry <img src="biggrin.gif" border="0">

    [ 12-03-2001: Message edited by: 570eck ]</p>
    the truth never hides for long

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    Sure there is a differnce. First as always is safety, two is better than one. But you have to look out for opposing streams, such as pushing fire at each other! <img src="eek.gif" border="0"> Next would be manuverabilty, 1.5 is easier to move around than 2.5. Also with 2 streams you can cover exposures more rapidly if need be, rather than wait for manpower to pull another line. Which brings the next point if you don't have the manpower maybe you have to go to the 2.5 to hold it down until backup comes. But if what you are asking is which would put out a fire quicker 2 1.5's or 1 2.5 it would depend on the operator, nozzle, seat of fire and materials involed. So as with all fires you don't know until you and your team get there.
    the truth never hides for long

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    We use 2 1/2 and run 3 man eng so we use the one line att. until 2nd due eng gets thier.

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    Why not one 1.75" line at 250gpm?
    It's only my opinion. I do not speak for any group or organization I belong to or associate with or people I know - especially my employer. If you like it, we can share it, you don't have to give me credit. If you don't, we are allowed to disagree too (but be ready to be challenged, you may be on to something I'm not). That's what makes America great!

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    A garage fire contained to one room? If you can get at the fire with the 2.5" then there should be no difference.

    unless, of course, your two 1.5" pre-connects are plumbed for Class A and your 2.5" is not.

    (Had to get that one in.)

    Don

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    Wink

    We only have 1.5 and 2.5 hose. I was of the impression that one 250 gpm line had more punch to knock down than 2 125gpm. I guess the bottom line is the gpm you put on, not how many lines it takes to get it on.

    Islander: I don't tink using class A foam will reduce the required flow to knock down the fire.

    <br />But it sure helps to keep it down.

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    GPM

    Making the assumption that we are talking about the same type of nozzles on each size line, I would pick the two line option if manpower was not an issue.

    The reason for this is simple. If we know that we need 250-gpm to beat this fire and we also know that BTU absorption from a fire stream is based on surface area of the water then two lines flowing 125-gpm each (250-gpm total) would offer more surface area for heat absorption than a single line flowing 250-gpm.

    This being the case the higher surface area would put the fire out faster. Would you notice the difference? Probably not, except when you start reloading your hose lines <img src="smile.gif" border="0">

    Just me two cents worth.
    Kirk Allen
    First Strike Technologies, Inc

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    The line size isn't as important as the flow. If you need 250 GPM to knock the fire down then use 250 GPM from one line. Reach is an important issue. A 1.5 or 1.75" line doesn't have the reach or "punch" that a 2.5" line does. <br />Aside from that the average 2 1/2 car garage doesn't need 250 gpm to extinguish. If it is filled with so much stuff that you need the larger flow then stick with the 2.5" again better reach and penetration.

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    ::::Why not one 1.75" line at 250gpm?

    Everyone knows Mongo it is the size of the hose not the amount of water flowing out of it that puts out the fire.

  11. #11
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    GPM,

    If the fire requires 250gpm to extinguish it you are better off flowing that from one line. The added punch of the bigger stream as well as its ability to survive passing through the thermal currents (not being turned to steam too soon to affect the fire) are a major benefit of the higher flow from one line. The problem with multiple lower flow lines is that many times while the flow of the multiple lines equals the required fire flow it is ineffectual because the water never reaches the base of the fire.

    If the required flow is 250 gpm it does not matter what size hose you use as long as it is capable of flowing 250 gpm in a usable fire stream.

    You know what my choice would be...a 2 inch line. But since your options are either 1 1/2 or 2 1/2, the 2 1/2 should be your choice. And in reality it will take about the same manpower or less manpower to operate the 2 1/2 inch line as the multiple smaller lines. Of course you should have a back-up line in place to protect the attack crew.

    Take care and stay safe,

    FyredUp

    By the way, I hope you are enjoying your snow up there. We had 60 degrees today and forecast of 60 tomorrow. Man am I loving this!!

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    Oh yeah, thanks for reminding me the7tower. One of the OT's in the station tonight was commenting to a boot on this very thing.

    "I been doing this for pert near 40 years and lemme tell ya, when a ring on a nozzle has 125gpm on it, that's all the line iit fits on is designed to flow. If it would flow more they'd make the nozzle be able to do it."

    Well, ya'll know me...

    "Hey old dude, how come Elkhart says this nozzle will flow 325?"

    "Smart*****, that's a 2.5" nozzle that you had 1.5" connections put on, and 325 is too much for the 2.5"."

    "But wait, even a 15/16th tip for an 1.5" line flows 185 at it's designed pressure?"

    "Shut up will ya, you'll confuse the kid."

    "Yeah OK, you explain that one to her then."

    "I ain't gotta explain it, that's just the way it is."

    I tell you, if we can ever get tradition, real life and physics on the same page we'll stop beating ourselves to death.
    It's only my opinion. I do not speak for any group or organization I belong to or associate with or people I know - especially my employer. If you like it, we can share it, you don't have to give me credit. If you don't, we are allowed to disagree too (but be ready to be challenged, you may be on to something I'm not). That's what makes America great!

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    There is no decision. The 2 1/2. Two lines are not better or more productive than one. What someone suggested that a 1 3/4 at 250 gpm. What pump pressure is that?

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    150 feet 1 3/4" Angus Hi Combat hose 250 gpm needs an EP of 200 psi

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    Is the garage in the back of the house? What if the house has a swimming pool and you've got 50 firefighters...each having their own 5 gallon bucket...if they formed a line and rotated between throwing their buckets of water and refilling in the pool over a one minute cycle...would this be as good as a 2-1 1/2" or 1-2 1/2" line flowing 250GPM?

    [ 12-06-2001: Message edited by: gah74 ]</p>

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    I tried to resist.....<br />to answer your question with some questions:<br />Is this "garage" the first fire of the shift?<br />Is this "garage" the last fire of the shift?<br />Is it attached to a house?<br />3 or 4 on the engine? ..5????<br />1 engine...2 engines...a full "still" assignment?<br />For a requried flow of 250... it's goin pretty good right? <br />If it's not attached....exposures???<br />1st. line on exposure????<br />If it's not attached and there is no exposure problems....where are the marshmellos?

    Oh yeah.... I saved this on a tape recorder for just such an occasion"WATER SMOTHERS FIRE" not only cools but smothers also....So you don't have to break it into "Tiny Drops of Water" to extinguish it (That's for Andy)!
    FTM-PTB
    trk4

  17. #17
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    The point is 1 or 2 streams. I just made up the garage thing. Lets just say it's goin pretty good and 250 gpm will do it. Is one choice more effective than the other?

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    If your fire requires 250 g.p.m. to extinguish. You are better off to attack with a 2 1/2" (here is the key)it offers better reach and penetrating power to cool the seat of the fire resulting in faster knockdown. You can use two 1 1/2" lines but the streams would evaporate more before reaching the seat of the fire (You would actually use more water trying to extinguish the fire), eventually the fire would consume enough material that the 1 1/2 lines would be effective. If you used class A foam you still need the same types of hose lines and flows. Foam just allows water to penetrate material more easily by breaking surface tension.

  19. #19
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    If the atack is an exterior attack you are probably better off with two 125 gpm streams or four 60 gpm streams.

  20. #20
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    Sorry, more questions...<br />What kind of structure?<br />Anybody in there?<br />Where IS the Truck?<br />Enough questions...<br />If you need 250gpm. then do it with one line, if you have enough manpower.<br />If you take 1 line INSIDE, then take another(same or greater flow)...remember MANPOWER!!!<br />Oh yeah... you are gonna need a LOT of people to move 2-2.5" lines (inside, up stairs, around corners....did you say this fire was on the 3rd. floor?)!
    FTM-PTB
    trk4

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