Math Formulas Flashcards
Pump Pressure Discharge
(PDP Formula)
PDP = NP + FL
NP = Nozzle Pressure
FL = Friction Loss
Standard Nozzle Pressures
(psi)
SB Handline = 50 psi
Fog Nozzles = 70 psi
SB Master Stream = 80 psi
Nozzle Reaction Formula
(Smooth Bore)
NR = 1.57 x D² x NP
Nozzle Reaction Formula
(Fog Nozzle)
NR = .0505 X GPM X √NP
Flow Rate Formula
(Smooth Bore)
GPM = 29.7 x D² x √NP
(Convert diameter to a decimal)
Friction Loss Formula
FL = C x Q² x L
C = Coefficient
Q = Quantity of water flow (gpm) / 100
L = Length of hose (ft) / 100
Elevation Pressure
(EP)
5 psi for every 10’
+5 for elevation gain
-5 for elevation loss
(does not include ground level)
Appliance Loss
(AL)
10 psi for handline appliances:
-Wye
-Siamese
-FDC
-Manifold
*When water flow is ≥ 350 gpm, otherwise 0 psi
25 psi for master stream appliances
-Ground monitor
-Standpipe
-Elevated master stream
Total Pressure Loss
(TPL)
TPL = (C x Q² x L) + AL + EP
Friction Loss + Appliance Loss + Elevation Pressure
(Does not include nozzle pressure)
Pump Discharge Pressure
(Wye w/ Equal Lines)
PDP = NP + FL
FL = C x Q² x L
Q is flow rate the sum of all eye discharges.
Supply line FL + Discharge line FL (one line) + AL ( if flowing ≥ 350 gpm)
Pump Discharge Pressure
(Wye w/ unequal lines)
PDP = NP + FL
FL = C x Q² x L
Q is flow rate the sum of all the discharges.
Supply line FL + Discharge line FL (longest line) + AL ( if flowing ≥ 350 gpm)
2nd line will need to be gated down at wye to appropriate pressure.
Pump Pressure
(Siamese Line)
Calculation Methods
Split Flow Method
Coefficient Method
Percentage Method
Pg. 143-145
Friction Loss Coefficients
(1 3/4”, 2”, 2 1/2”, 3”, 5”)
1.75” = 15.5
2” = 8
2.5” = 2
3” (2.5” couplings) = 0.8
3” = 0.67
5” = 0.08
Pump Discharge Pressure
(Elevated Master Stream)
PDP = NP + FL + AL + EP
FL = (C x Q² x L)
Nozzle Pressure + Friction Loss + Appliance Loss + Elevation Pressure
Pump Discharge Pressure
(Standpipe)
PDP = FL (supply) + FL (standpipe) + EP + FL (attack line)
