The Physics of Fireground Hydraulics
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Cheat Sheet
After learning the equations for friction loss and engine pressure, all that's left is knowing which values to plug in.  While all the pressures listed below are engineered using Bernoulli's Equation, memorizing each value makes calculating engine pressure much easier.

 Attack Pressure (Pre-calculated)
Standard Attack (150 gpm)            Blitz Attack (250 gpm)
Hose Pack (150ft)                  140psi                                        200psi
Preconnect (200ft)                 150psi                                        230psi
Standpipe*                             170psi                                        230psi
Skidload*                               145psi                                        205psi
*Add FL for 3" for elevation

Supply an Engine.....50psi
                                                       Nozzle Tip Pressures
Hand Held Fog.........................100psi
Hand Held Straight Stream......50psi
Mounted Fog............................100psi
Mounted Straight Stream..........80psi

                                                    Appliance Friction Loss
Gated Wye/Small Appliance.....5psi
Monitor......................................15psi
Standpipe..................................25psi

                                                    Coefficients
1 3/4".......... 15                        3"............. 1
4"................ 0.2                      5".............. 0.1