fire pump calculations

[Neel.mech]

hello everyone , i need some help regarding calculating residual and static pressures in a fire water system.i am working on a closed loop pipe network system , with a fire demand of 2500 gpm for 2 hours . i have calculated frictional losses using longest run method ,i could find the frictional losses which is almost 30 psi...can anyone help me regarding this concept of minimum residual pressure required at the hydrants..and how it works? and how can i determine a suitable pressure range for fire pump..

 

[ProcessHVAC]

You can use software like EPANET to model the system. You need to figure out details as to how you intend to supply your flow (i.e. hydrants, size, how many?) get hydrant suppliers data for working flows and pressure differential. The intent is to make sure you are keeping a minimum residual pressure at the distribution systems when you are delivering the fire flow.

 

[Neel.mech]

thanks for your reply ProcessHVAC. As i am just starting my career , do you have any idea what is the normal discharge pressure at the hydrants..

 

[ProcessHVAC]

I do have for sprinklers and hydrants I have used in my designgs. But again, you need to talk to whoever you are are specifying or purchasing, here is a sample hydraulic performance chart for a Mueller hydrant:

http://kb.eng-software.com/question...t+in+PIPE-FLO+Professional+or+Flow+of+Fluids?

 

[Neel.mech]

ProcessHVAC , THANK YOU VERY MUCH...

 

[MortenA]

If i were you i would google manufactures of fire hydrates etc (if you dont already have a specific model). They usually have lots of info incl. a capacity vs. upstream pressure curve.

 

[MortenA]

i just checked it a little myself and at random found this is less than a minute:

http://www.elkhartbrass.com/files/aa/downloads/brochures/ScorpionEXM_datasheet_10.14.13.pdf

 

[Neel.mech]

thank you MortenA...