Friction losses fire piping system

Hi,
I want to calculate friction losses on a fire hose piping closed loop system, 4 farthest hose reels opened at the same time. When calculating, must I consider all pipes or only those preceeding these 4 hose reels? and what are the steps to do this calculation?

Thank you

Sorry it took so long to respond, but I emailed my Fire Safety Hazards Recognition prof, and this is what he had to say:

[quote]

So, to calculate the friction loss from the FDC to the four farther hose reels, you will need to determine the flow from all four hose nozzles and all the pipes between the FDC and the nozzle where water will be flowing, not necessarily all the pipes. I hope this helps!
[/quote]

Remember the formula for friction loss is FL = 2Q² + Q if the flow is greater than 100GPM, or 2Q² + ½Q if the flow is less than 100GPM.

I hope I helped!