This internal website is for City of San Rafael employees. The public website is www.cityofsanrafael.org.

Hose Flows

The most important characteristic of fire hose is the quantity of water that will flow through it, given the size of the hose, rated working pressure and friction loss per 100 feet.

The maximum practical flow determines the uses to which the hose can be put. Hose use is usually a compromise between maximum flow and maneuverability. 3/4 inch booster hose very maneuverable, but limited to a maximum flow of about 20 GPM. 4 inch hose will flow over 1000 GPM but can only be used as supply because it cannot be moved more than a few feet once charged with water.

The rated working pressure is the uppermost pressure the manufacturer recommends be normally used with the hose. Although fire hose may be factory tested at 400, 600 or 800 pounds per square inch, the working pressure is normally 200 -300 pounds. This corresponds to the annual hose test conducted by the Department. The chart below lists hose sizes, types and friction losses at maximum practical gallons per minute. This maximum practical flow is not absolute but reasonably consistent with safety and hose and pump capabilities.

 

 

Size/Type

 

 

Working Pressure

Friction Loss per 100 feet at

Maximum Practical Flow

 

Maximum Practical Flow

3/4” Booster 600 PSI 50 PSI 20 GPM
1” Single Jacket 250 PSI 35 PSI 35 GPM
1” Rubber 300 PSI 44 PSI 40 GPM
1 ½” Single Jacket 250 PSI 33 PSI 100 GPM
1 ½” Rubber 300 PSI 50 PSI 125 GPM
1 ¾” Double Jacket 250 PSI 50 PSI 180 GPM
1 ¾” Rubber 300 PSI 60 PSI 200 GPM
2 ½” Double Jacket 250 PSI 30 PSI 350 GPM
2 ½” Rubber 300 PSI 32 PSI 400 GPM
3” Rubber 250 PSI 30 PSI 600 GPM
3 ½” Double Jacket 250 PSI 35 PSI 1000 GPM
4” Rubber 250 PSI 30 PSI 1250 GPM

 

These maximum practical flows are, of course, dependent on the hose lay length, pump capability, hydrant supply and nozzle or appliance used.

Close window