Hi all the fighters here, I'm still new to fire-fighting so wanna ask you guys some questions regarding to best pipeline to be used (might be old topic, and sorry if it was):

With same amount of water, pressure, nozzle and etc.

Which kind of hose would you choose? 2 inch or 2 and half?

Which one is more water saving during lacking of water sources?

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The 2 inch hose use less water. That being said, I would have to use the 2 1/2 inch hose because my F.D. does not have any 2 inch hose.
thx Brian,

I thought that nozzle playing the role of saving water...
I agree with Jim
What are ya fighting. Here we use 1 3/4 and duece anda half
You can save a little water with your nozzle setting, but the different hose diameters make the difference in how much water will flow with the same pump pressure.
sorry guys... just lil discuss coz i'm still new...
By "pipeline" do you mean a water supply line or an attack line?
2" line is a little more maneuverable, but are limited with GPM as opposed to a 2 1/2". If you are already carrying 1 3/4" line as an attack line, why have your next bigger line only a 1/4" more diameter?

I see the 2 1/2" being a bit more versatile as a supply line, an attack line, used for offensive or defensive, the bigger diameter does give you more GPM.
This is the guideline for using the 2 1/2

A :Advanced fire on arrival
D : Defensive ops
U : Unknown locaiton and or extent of fire
L : Large Uncompartmented area
T : Tons of water needed
S : Standpipe ops

If you fire meets one of those criteria you need a 2 1/2 or larger.

Also check these out:


Good luck and welcome to the best job in the world
What an outstanding guideline Robert.

I would add another guideline for determining friction loss... HANES (as in tee shirts / underwear)

H :Hose diameter
A :Appliances needed
N :Nozzle Pressure
E :Elevation
S :Standpipe

Train as if your life depends on it... because it does!

Welcome to the biz. You will find this forum an excellent place to ask questions you may feel shy about in your department. Read all you can and check out some of the instructional videos on YouTube.

Regarding 2 1/2" attack line, this is a beast of a line and requires a lot of manpower to advance and manoeuvre. For exterior operations, it's a good option as it's portable and easily moved. It will put out a hell of a lot of fire if used properly.

For interior operations, the situation changes. It is very difficult to move it in most buildings and can hinder your ability to attack a fire. Here's a LODD caused in part by the crew's inability to advance the attack line past the first room.


Don't underestimate the 1/4" of extra diameter. The diameter of the hose increases at the square of the radius (diameter=3.142 x Radius(squared)) so you're getting a fair bit of extra water with a 2". We used to carry 1 3/4" as our primary attack lines, a 2" with a smooth bore for the bigger stuff, 2 1/2" for exterior ops.

FWIW - a well deployed, well used hose line is more effective than a massive one poorly used. Here's a video of a massive housefire extinguished with 1 1/2" lines.


technique trumps tools every time.
I agree with your comments about the 2 inch hose, and technique trumping tools.....thats why the 2 1/2 can be stretched interior with 2 to 3 guys with the right technique.

As for the PG video....I think this proves the need for the 2 1/2 that 1 3/4 in my opinion did not put that fire out. It did not have the GPMS to do so. The fuel simply burned away enough over time in order to make it an 1 3/4 fire. Besides the fact that they accomoplished nothing, saved nothing. The 2 1/2 (properly tipped witha smoothbore nozzle) would have been able to hit the fire from a safe distance and provide 300+gpms. The 1 3/4 on the fire in question was a completely self serving (do what I wanna do not whats right) and "Teddy Bear Tactic" (mad them feel real good but in reality had no bearing on the outcome of the fire)

Again just my opinion.
correction - I use the word "diameter" where I should say "cross section." Meh, you get my drift, for a small increase in diameter, you get a large increase in available waterway, and an even larger reduction in friction loss.

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