Fire hose flow rate
Fire hose flow rate
(OP)
Here isa simple problem I cannot get my head around. I hav100 ft. of 2 inch fire hose. Pressure at the hydrant is 60 psi static. What will I get for a flow rate for this hose? Hose is open to atmosphere. Ia sure I have done this in the past but I feel am missng something
Richard A. Cornelius, P.E.
WWW.amlinereast.com





RE: Fire hose flow rate
"If the residual pressure at the hydrant is allowed to fall to 20 psi what flow will be available ? "
If stated this way it is fairly simple to use both the Darcy -Weisbach equation and the Bernoulli equation to calculate the available flow at 20 psi residual pressure.
You will need to look up the friction factor (f) for the 2" hose. It is probably about 0.020. Total available head is 60 psi-20 psi or about 40psi which is equivalent to 93.6 feet of water.
The flow can be calculated by trial and error or by using a program such as EPANet2.
good luck
RE: Fire hose flow rate
RE: Fire hose flow rate
RE: Fire hose flow rate
I should have said, "If the residual pressure at the NOZZLE is allowed to fall to 20 psi what flow will be available ? "
Using the Table provided in my previously posted link, I get a flow of about 248 gpm and a friction factor "f" of about 0.018.
RE: Fire hose flow rate
You really need to know the supply system characteristics to do it accurately. If it has "unlimited" supply, then you can assume pressure remains at 60 psi when the hose is flowing. Run the bernoulli eguation between the hydrant and the nozzle, account for hose friction loss, nozzle loss, and dynamic head at exit. pressure at the outlet is zero.
If you have hydrant flow test data, then you include this data in the equation, as the pressure will drop some at the hydrant.
RE: Fire hose flow rate
If these factors are not taken into consideration, then you are just asking how much flow goes through a fire hose.
RE: Fire hose flow rate
http://www.tucows.com/preview/279857
As I noted before - go to your local fire dept. they should have all the info you need.
RE: Fire hose flow rate
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RE: Fire hose flow rate
Richard A. Cornelius, P.E.
WWW.amlinereast.com