# Water in 4 inch hose and 5 inch hose

• 03-07-2000, 07:49 PM
BFD 210
Water in 4 inch hose and 5 inch hose
If anyone can help me determine the amount of water per foot in 4 inch hose it would be greatly appreciated. I believe that a 5 inch holds approximatly 1 gallon per foot. I have found this in reference but i cannot find 4 inch. Thanks for any help.
Stay safe
• 03-07-2000, 08:09 PM
Dalmation90
Sure BFD --

Fire hose is a cylinder.

The volume of cylinder is determined by the formula: pi(r^2)h
r is the radius. For 5", thats 2.5"; for 4" it's 2" The little ^2 is computer shorthand for squaring - multiplying the radius by itself.
h is height, or in the case of hose the length.

So, for 12" (1 foot) of hose is:
5" -- 3.14x(2.5x2.5)x12 = 235 cu. in
235 cu. in /1728 = 0.13 cu. ft.
4" -- 3.14x(2x2)x12 = 151 cu. in.
151 cu. in /1728 = .09 cu. ft.

Ok...I know, you want gallons! 1 gallon of water = 0.13 cu. ft.

So 1' of 5" hose holds .13/.13 = 1 gallon
and 1' of 4" hose holds .09/.13 = .7 gallons

Matt http://www.firehouse.com/interactive/boards/smile.gif