# Thread: The right line for the amount of fire

1. ## The right line for the amount of fire

Hey everyone, I am looking for a document that talks about the correct size line for a given volume of fire. I know BIG FIRE BIG WATER, but does anyone have a scientific document to back this up. I would like to try and get my department away from pulling inch and a half lines when a structure is VERY involved.

Thanks

2. Scientific? Not sure where you will find specific research articles on such. You might try references made to the formulas used by Iowa State, NFA, and the ISO found in most any fire hydraulics book. Surely the research is in the public archives somewhere by now...

Google "Fire Flow Research" for starters.

3. ## 2" or 2 1/2" acronym, etc.

D = Defensive Operations
U = Undetermined Location
L = Large Building
T = Tons of Water
S = Standpipe

2. Fire flow formula. Length x Width divided by 3 = GPM for 100% involvement, per floor. Add 25% for each interior exposure (floor above fire floor) or 25% for each exterior exposure for each side that has exposed another structure to fire.

3. "Guide for Determination of Needed Fire Flow" ISO, Edition 5/08

4. If you have no man power large diameter lines are not going to work, why? They wont work cause the guys on the line will get their azz kicked faster! And once they are fatigued you are in a dangerous situation, many can become disoriented, loss of balance etc. the factors involved just create a possibly deadly situation. If its residential take the 1.75 if its commercial, 2.5 but if you only have two guys on a line, go smaller, better to get some water in there than none when the guys have to bail cause they are too tired.

5. Originally Posted by jonnyirons2
If you have no man power large diameter lines are not going to work, why? They wont work cause the guys on the line will get their azz kicked faster! And once they are fatigued you are in a dangerous situation, many can become disoriented, loss of balance etc. the factors involved just create a possibly deadly situation. If its residential take the 1.75 if its commercial, 2.5 but if you only have two guys on a line, go smaller, better to get some water in there than none when the guys have to bail cause they are too tired.
I agree with this to a point. For residential - for an average house its 1 3/4". A McMansion might need 2 1/2". For Commercial - is usually a 2 1/2" but in some cases (small number), 1 3/4" might be plenty.

Now, if you have a fire where 2 1/2" is called for and you lack the manpower to use a 2 1/2" effectively, I don't think backing down to 1 3/4 is a smart choice. You wanted the 2 1/2" for a reason and that hasn't changed. Perhaps a re-evaluation of tactics is needed to accomidate manpower limitations.

6. Well if you can not supply the 2.5 with the man power than just go defensive outside. And have you ever tried to put a bow in a 2.5 in a hallway?

7. Originally Posted by jonnyirons2
Well if you can not supply the 2.5 with the man power than just go defensive outside. And have you ever tried to put a bow in a 2.5 in a hallway?
Honestly I haven't. Where I am is volunteer and mostly SFD's except for a wal-mart and few other commercial buildings. We also run CAFS so we get a lot of milage out of the 1 3/4". I can't say I've seen the 2 1/2" get pulled outside of training/hose test either. (of course I'm fairly new though)

I do think you're right though. If you don't have the manpower to handle the 2.5" and the fire calls for it - your better off going defensive until you can get the manpower.

8. my brain is straining to remember this one, and correct me if im wrong please.

the science behind volume delivery is, ideally a gallon of water will absorb 537 btu's when completely converted to steam. In order to put the fire out, you must apply enough water to exceed the btu's, or "overwhelm if you will.

on a small scale for simplicity, lets say you have a sofa burning. 16,000 btu's. theoretically it will take 29ish gallons of water to extinguish. the quicker you can deliver this volume, the quicker the fire goes out. a 2.5 handline will deliver 2x's the volume of a 1.5 in the same time. or the same gallons in half the time. now make that a well involved house or garage with lots of crap, your talking millions of btu's.

whether you deliver the gpm via 2, 1.5 handlines for mobility, or a 2.5.. thats the science.

as far as getting your dept to change, all the above discussed in the thread is important. manpower, water supply etc. a 2.5 is a boat anchor without guys to move it, and will blow your wad before you know it without water...

9. Originally Posted by jonnyirons2
If you have no man power large diameter lines are not going to work, why? They wont work cause the guys on the line will get their azz kicked faster! And once they are fatigued you are in a dangerous situation, many can become disoriented, loss of balance etc. the factors involved just create a possibly deadly situation. If its residential take the 1.75 if its commercial, 2.5 but if you only have two guys on a line, go smaller, better to get some water in there than none when the guys have to bail cause they are too tired.
You are kidding right?
better to get some water in there than none when the guys have to bail cause they are too tired
What's the point? Either you are putting the fire out or just delaying the inevitable. And taking too small of a line inside against too much fire makes your situation a loser and dangerous to your crew from the get go. I can only see one reason to use this tactic and that is to try to protect a rescue crew. Certainly not as a realistic fire attack since you know before you enter that the flow isn't big enough.

I still wonder why more FD's don't take advantage of 2 inch lines. We use 2 inch and can flow 300 plus gpm through it and do it most of the time with 2 people. If you have to go over 300 feet do like we do and stretch 3 inch line with a hundred or so feet of 2 inch on the end. Perfect solution? For us yes. For anyone else? Perhaps. It does take opening your mind to the possibility of something far different than what you do now.

10. Fyred I dont know if you are drunk or not, you posted kind of early. No I am not kidding. Have you seen the physical requirements for volunteer depts? I want to see what you are rolling with. Even with a 4 man engine here in NY its a real murder on a 2.5 line and we are well aware we have another 3 companies coming if its a fire. Waiting for another 2 to 3 engines is not a liberty you can take in a volunteer dept, 2 to 3 men, yes, but not another 8-10 members.

11. Experience! Yep,hauling a Deuce is a bitch.But,in some cases,if you don't haul it you'll be making a rapid exodus when you might have made the stop with it.It's a ongoing battle here to get the troops to properly size the line to the job.Our smallest line is a 1.75 so that works in our favor.When in doubt,go BIG!Nozzles play a critical role in how effective a line is so size them correctly for the job you're trying to do(and the hose size).Good luck,T.c.

12. Most residential fires get a inch and three quarter pre connect.. our first alarm assignment will put 15 to 17 ff s on the fireground. 2 engines a squad[rescue engine ] and ladder co. so a second line is comming quick .. we have had great luck knocking down most fires with inch and three quarter lines.

large volume of fire / commercial will get a 2/1.2.. we have a pre connected 200 ft. length of 2/1.2 straight bore nozzle . this is great in terms of tip pressure being 50 lbs. as opposed to the combo nozzle we use for the bed of 2 / 1.2 that requires 100 lbs at the tip .. big difference in terms of taking a beatin like you guys mentioned. but how often are we totally sure 200 ft. will make the push . with respect to manpower issues,,,, when in doubt , go with a big line ... you can never have too much water ...

i would much rather take the ballbreaking that will come with taking a big line to a small fire as opposed to taking a small line in only to retreat and watch the rest while sitting on top of the line i should have taken in the first place..

13. Originally Posted by LeatherHed4Life
my brain is straining to remember this one, and correct me if im wrong please.

the science behind volume delivery is, ideally a gallon of water will absorb 537 btu's when completely converted to steam. In order to put the fire out, you must apply enough water to exceed the btu's, or "overwhelm if you will.
Actually, a gallon of water will absorb around 9000 BTUs when converting to steam. That's what we were taught at least.

14. Originally Posted by jonnyirons2
Fyred I dont know if you are drunk or not, you posted kind of early. No I am not kidding. Have you seen the physical requirements for volunteer depts? I want to see what you are rolling with. Even with a 4 man engine here in NY its a real murder on a 2.5 line and we are well aware we have another 3 companies coming if its a fire. Waiting for another 2 to 3 engines is not a liberty you can take in a volunteer dept, 2 to 3 men, yes, but not another 8-10 members.
Jonny,

Thanks for your concern about my sobriety. I can't drink because I am a diabetic so you can remove wondering if I am drunk from your reasons to shake your head at my answers.

2 inch hose is what my volly FD uses. 2 inch not 2 1/2, but2 inch. We found that with 2 people it is almost as easily advanced as a 1 3/4 inch line and will easily flow 300 gpm if we need it to.

What do we roll with? Depends on the time of day and the day of the week. I have rolled the first engine on occasion with 3 and at other times with 5 or 6. Generally we can count on 6 to 12 at a working fire. We use 2 inch hose because frankly we know that is we screw up the hose size choice we may not have another crew immediately available to advance the BIG LINE. The only size handline we use is 2 inch and we flow from 160 to 300 with that line.

Your 2 or three engines are rolling within seconds of being toned, our mutual aid is coming from 3, 5, 8 and 12 miles away. So the initial hit is very important and big flow from our intermediate sized hose works for us.

By the way I am also a career FF and we are a traditional 1 3/4 inch and 2 1/2 inch attack line department.

15. WOW thanks for the input, very much appreciated. I as well think it is better to go BIGer so you can go HOME, than to go too small and create a parking lot. The idea of 2" hose is one that sounds good, maybe upgrade from 1 3/4 and 2 1/2, to 2 and 3 inch. Take care STAY SAFE

Gweedo

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