# Thread: Flow Capacities for fire hose

1. ## Flow Capacities for fire hose

I've googled and looked everywhere without success for a chart, or listing of flow capacities for fire hose for these sizes 1 3/4", 2 1/2", 3", and 5". If anyone could help with providing these figures (in terms of GPM's) or give a link to a source that could help, it would be greatly appreciated. Even "close" figures would be helpful.

Woody

2. ## Flow volumes of fire hose

Woodie:

There is no single flow volume for fire hose. It all depends upon how much pressure you are able to supply in getting the water through the hose line. Then the length of the hose directly affects the amount of pressure it will take. For 1 3/4" hose at 125 gpm it takes about 16 psi per 100 ft. For a flow of 150 gpm it will take a pressure of 25 psi per 100 ft. At 180 gpm about 36 psi per 100 ft. If pumping a 200 ft. preconnected 1 3/4" line with a 150 gpm fog nozzle at 100 psi, you will need an engine pressure of 150 psi. That is 50 psi for overcoming the friction loss in the hose and 100 psi to properly operate the nozzle.

When sending water through a 2 1/2" line at 100 gpm it takes about 2 1/2 psi per 100 ft. of hose. At the same flow rate, 500 ft. of hose will require 13 psi to move that volume of water. At 300 gpm through 2 1/2" hose it requires 22 psi per 100 ft., or 110 psi through 500 ft of 2 1/2" hose. At 400 gpm the 2 1/2" hose needs a pressure of 40 psi per 100 ft. to push it through, or 200 psi to move it 500 feet.

3" hose has a loss about equal to the desired flow divided by 100 and that number squared. Example: 500 gpm through 100 ft. of 3" hose. Move the decimal 2 places to the left and the 500 becomes 5 then square the 5 or 5 X 5 = 25 psi per 100 ft. will be the friction loss at 500 gpm. You could force 1000 gpm through the 3" hose and would need a pressure of 10 X 10 = 100 psi to get that flow through one 100 ft section of 3" hose. If you try to move 1000 gpm through more than 250 ft. of 3", you will exceed the rating of your pumper at over 250 psi. Not only that, but you will need a 2,000 gpm pumper to reach the 1,000 gpm at 250 psi.

5" hose has a friction loss equal to 1/15th that of 3" hose. The same 1000 gpm can be pushed through 100 ft. of 5" hose with only 6 psi. you can send that 1000 gpm through 2,500 ft. of 5" line with a pressure of 150 psi and could do it with a 1,000 gpm pumper.

Kuh Shise

3. Sorry, I should have specified length of hose...per 100' of hose, I'm looking for the capacities, in gallonage, of flow for the specified diameters. For instance, I know that 200' of 1 3/4" attack line can flow upwards of 200+ gpm (obviously depending on nozzle and pressure) but, I was, I guess, looking for the max capacity of the specified gpm's for the specified hose diameters, or for that matter, the "typical" capacities for those diameters. Thanks Kuhshise.

4. Pressure Loss in PSI per 100' Hose
If they don't list a specific flow, it's either impractical to do in real life, or the friction loss is negligible.

The entire TECHNICAL DATA section of Elkhart's Catalog has a boatload on data.
23 pages of it.

5. Thank you for the links!

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