what line do I pull?

[fergus]

I am not an officer, but aspire to one day be one. I do my best to read textbooks and magazines and talk to older guys, and I learn a lot from them. One thing I am unsure of is this- whats the best way to determine how many GPMs are needed? I've learned about A/3 and V/100 (and found them to give very different answers), I've had officers say that they'll just guess based on their experience, and I've seen people who will pull a 2 1/2 on everything (even car fires), just to be sure. Obviously, one does not have time to measure the entire building, determine the percentage involved, and plug it into a sprinkler flow formula on a laptop to get the exact flow, right down to CCs, but there must be a quick, fairly accurate method out there somewhere. For you experienced company officers- how do you determine what line to pull?

thanks!

[Looper]

General rule of thumb for me.....

Smoke showing --- 1.75" with 200gpm nozzle
Heavy fire showing --- 2" with 350gpm nozzle
Heavy fire in commercial bldg --- 3" with 500gpm Blitzfire monitor

Hope this helps.

[Fire/Rescue43]

My general rule of thumb for line size...

Smoke showing to 1/4 of the strucuture involved 1.75" lines.

1/2 + of the strucutre involved 2.5" lines.

3/4 to fully involved 3" lines w/ moniters.

The other way to determine fire flow is to check your pre-plan on the structure. As part of the pre-plan you should have fire flows figured for the strucutre based on precentage of involement.

When in doubt remember the old saying "Big fire, big hose"

Stay safe.

[RyanEMVFD]

There is a chart in the Essentials of Firefighting book titled "Hose Stream Characteristics". Basically a 1½ inch line would be used for a devoloping fire still small enough or sufficently confined to be stopped with relatively limited quanity of water. For quick attack. For rapid relocation of streams. When manpower is limited. When ratio of fuel load to area is relativly light. For exposure protection. For a 2½ inch line would be for when size & intensity of fire is beyond reach, flow or penetration of 1½ inch line. When both water and manpower is ample. When safety of men dicates. When larger volumes of greater reach are required for exposure protection.

[PuffyNPFD]

Rule of thumb I was taught by an old salty Providence Fire Capt.
Fire from 4 or more windows or a commercial occupancy 2 1/2".
Everything else 1 3/4".

[stillPSFB]

G'day Ferg,

The Southern Cross on that flag is a little hard to pick, so is that an Aussie flag or a Kiwi one?

[JayTL]

Good rule of thumb:

Whatever you do, do something.

[fergus]

I appreciate everyone's input, thanks for the help!

psfb-
Thanks for noticing! That would be 4 stars- NZ.

[BFD196]

Here`s what I was taught, big fire, big water. When you have a large amount of fire showing it`s a good idea to take the 2 1/2, we`ll also pull it on any type of fire in a commercial building, the 1 3/4 is perfect for most routine house fires.

[HFDCLanger]

Why not give your crews a break and provide them with one line for every job? Pack a few 2" lines with flow ranges up to 500gpm (I won't get into tip selection) and your crew doesn't need to worry about which line to pull all of the time. Much easier to manuever than a 2 1/2" and eliminates the possibility of a 1 3/4" line being pulled on a 500gpm fire.

[FF.1205]

A general Rule of thumb I use is
Residential 1 3/4" unless to blitz attack it then 2 1/2"
Commercial / Industrial 2 1/2"
Experience has taught me that this when I do a size up.
If I know I can put it out with 1 3/4" then stretch it
If I think I can put it out with 1 3/4" then stretch a 2 1/2"
If I know I can put it out it out with 2 1/2" stretch it
If I think I can put it out with 2 1/2 then it's time to get out the deck gun.
All defensive structure fires you never go wrong with 2 1/2" and deck guns.


GOD Bless FDNY and ALL of the Lost Brother's and their families

Dave
FTM, PTB, RFB

[quintladder]

Hose size is no gaurantee of flow.

A 2 1/2" line could flow less than a 1 3/4" line, ie a 2 1/2" LINE WITH A STACKED TIP SET with a 1" tip in place versus a 200 to 250 fog on a 1 3/4" line. A 1 1/2" could flow more than a 1 3/4" line, ie a 30, 60, 95, 125 nozzle set at 95 on the 1 3/4" line, or simply not pumping enough to get the flow.

Wrong EP or nozzle type or setting and you won't get the flow.

It is far better to speak gpm than hose size.

In fact, a 2" line with the right nozzle and tip will always out flow a FDNY 2 1/2" line. A Chicago or LA 2 1/2" line flows 75 gpm more than a FDNY 2 1/2" line. A Las Vegas 2 1/2" flows 100 gpm more.

Odds are most FD's can justify a one size interior line fits all of 1 3/4" or 2 inch not 2 1/2". There has to be a point where you do not belong inside. If it takes twice to three times the crew on a 2 1/2" according to FDNY with their low flowing 2 1/2" line versus a 1 3/4" line that can flow the same amount why would you use it?

[FF.1205]

Quint
Depending on nozzles true. Yes, I can convert a 1 3/4" to a 2 1/2 by just adding pressure.
But the post didn't refer to wrong EP..thats should be reserved for another post.
Secondly, why would you have secondary "larger" lines set up to flow the same as what you can get from a 1 3/4"?

GOD Bless FDNY and ALL of the Lost Brother's and their families.

Dave
FTM, PTB, RFB

[41Truck]

I prefer things simple and easy. Remember K.I.S.S.?

Big fire = big water (2-1/2" line)
Small fire = small water ( 1-3/4" line)

As far as pressures go, we operate all lines at 80PSI. With that pressure you will get around the same GPM X 10 as the diameter of your line with a smoothbore nozzle. For example: if you have a 1-3/4" handline you will get approximately 175gal at the tip with a 15/16" tip and a 2-1/2" line will deliver approximately 250gal at the tip with a 1-1/8" nozzle.

[firemanred]

We use TFT fog nozzles, and Vindicator nozzles for fire attack. With the TFT's on 200 ft of 1-3/4" at 150 psi you get 125 gpm, for 200 gpm your engine pressure is 225 psi. That can work your pump pretty hard and decrease the available water for other lines. If you need a larger flow{using whatever rule of thumb you choose} go with bigger lines. A 200 ft 2-1/2" using the same TFT nozzle{midforce by the way} and a reducer will give you 350 gpm at 150 psi engine pressure. At that pressure you still have 100% of your pumps rated capacity for other lines, such as deck guns, monitors, or more 2-1/2" handlines.
As for the Vindicators used with 2-1/2" handlines you can get up to 475 gpm out of it at, off the top of my head at 130 psi engine pressure. My point is this, you should be willing to experiment with different options, and newer technologies to see what kind of flows you can get from handlines,etc. Tradition is a great thing, but its place is behind that of our safety.

[cilfd]

Keep it real simple - 2"; set it up right and you've got the mobility of a 1 3/4" with the some very respectable high volume flows that rival many a 2 1/2" set up; and you never pull the wrong line

[distchief60b]

i say start off with a minimum of 200 GPM on any working fire (smoke showing)in SFD. Then knock back to 100GPM for mop up.

In a commercial occupancy it should be the same..but if you have a heavy volume of fire go bigger... I suggest the Blizfire from TFT... Able to deliver up to 500GPM in less than 90 seconds from a preconnected 2.5" or 3" line with a max of two people.

To calculate it theoretically.... L x W x H divided by 100... then figure out the percentage of involvement.... 100 x 50 x 12 divided by 100 = 600 GPM for total involvement. 50% involvement would be 300 GPM (THEORETICALLY according to text books) Figure 2 firefighters for every 150 GPM Flowing.

[ltdanfireman]

alot of times at a god working fire the wrong line is pulled for the job but a system that we use is 1-3 rooms 1 3/4" anything bigger 2 1/2 if the fire is kicking our butts and we have a backup line pulled we pull a size bigger then they did if we are going defensive on a fully involved house we pull the 2" or 2 1/2". on our engines we have 2 crosslays of 1 3/4" 150' and 200' then we have a preconnected 200' of 2" in hte hose bed and if needed we have 900' of 2 1/2 and a playpipe in hte hosebed also. on all our lines we have elkhart nozzles

[Engine1615]

Since we don't have hydrants in every location and rely on tenders we normally use 1 3/4 for all our attack operations, offensive and defensive, it seems to meet all our needs cause we are limited on water supply. we carry 1200 feet of 2 1/2 and never use it except in our supply from the tender to the engine cause we don't use drop tanks, or in a rare case hydrant to the engine.

[SquadHog]

Got to agree with 41truck and PuffyNPFD. The following "textbook" answer elaborates on this. It's simple and works well. Even if your dept. doesn't carry the same equipment the principles are the same:

The 1 3/4 inch handline is the primary attack line used at structural fires. This hose when used in conjunction with the 15/16 inch smooth bore nozzle provides an adequate fire stream and has better maneuverability and easier handling than the larger 2 1/2 inch handline. At a nozzle pressure of 50 psi, the 1 3/4 inch handline will flow approximately 180 gpm.

Company officers may order the stretching of 1 3/4 inch hose at fires as the initial line if its use is compatible with fire conditions and the extinguishing capability of the 1 3/4 inch hose is weighed against:
•The fire's magnitude, location and potential for spread.
•The occupancy of the structure and possible life hazard.
•The advantages to be gained by an increased speed in stretching and the increased mobility of the line, versus the need for a greater water delivery rate to control the fire.

The use of 1 3/4 inch hose would be inappropriate and a company officer should not order it stretched if any of the following conditions exist:
•The line is expected to be used from a purely defensive position.
•An advanced fire on arrival.
•A large volume of water is required to cool a superheated fire area.
•A large body of fire in a large uncompartmented area.
•When the officer cannot determine the size or extent of the fire or fire area.

Officers in command at fires may order 1 3/4 inch hose stretched as the second or third line when in their judgment it is compatible with fire conditions and their strategy of extinguishment/containment and/or exposure protection.

Officers in command at fires may order several 1 3/4 inch hose stretched into exposures when it is compatible with fire conditions and their strategy of extinguishment/containment and/or exposure protection.

All hoselines stretched from standpipes shall be 2 1/2-inch diameter hose with a 1 1/8 inch smooth bore tip. (a 1 1/4 inch tip is preferred by some companies, it flows 60 gpm more than the 1 1/8 and the friction loss is not excessive.) All hoselines lines stretched from standpipes shall be connected to outlets on floors below the fire floor.

The use of 2 1/2-inch hose line at standpipe operations is required due to the large volumes of water it can deliver with low friction loss per length. The 1 1/8-inch tip will produce a fire stream at extremely low pressure and is difficult to clog.