Name ______Date ______

Activity Sheet 3-4

Calculate Pump Discharge Pressure

PDP=NP + TPL

PDP= Pump discharge pressure in psi

NP= Nozzle pressure in psi

TPL=Total pressure loss in psi

Appliance, friction and elevation gain or loss

  1. What is the pump discharge pressure for flowing 200 gpm through a 2½” hoseline that is 200 feet long with a fog nozzle?

PDP = 100 + 2 (2)2 2 = 116 psi

  1. What is the pump discharge pressure for a 2½” hoseline that is 150 feet long with a 1⅛” straight tip?

For 2½” GPM = 250

PDP = 50 + 2 (2.5)2 1.5 = 68.75 psi

  1. A pumper is supplying a ladder pipe which is extended 65 feet. There is 100 feet of 2½” hoseline going up the ladder to the ladder pipe. One 3” hoseline 200 feet long from the pumper to the 2 ½” hoseline. The ladder pipe is flowing 500 gpm with a fog nozzle. What is the pump discharge pressure?

NP = 100

For 2½”on ladder GPM = 500 FL = 2 (5)2 1= 50

For 3” GPM = 500 FL = 0.8 (5)2 2 = 40

EP = 0.5 x 65 = 32.5

Ladder Pipe ≈ 25 (depends on ladder pipe)

PDP = 100 + 50 + 40 + 32.5 + 25 = 247.5 psi

  1. A pumper laid off a deluge gun at the fire scene and reverse laid to a hydrant 400 feet from the deluge gun. The deluge gun has a 1½” tip and is supplied by 4” hoseline. What is the pump discharge pressure?

GPM flow from nozzle = 600

For 3” GPM = 300 FL = 0.2 (6)2 4 = 29

Deluge gun = 25

PDP = 80 + 29 + 25 = 134 psi

  1. What is the pump discharge pressure for supplying 200 feet of 2½” hoseline with a 1⅛” straight tip handline?

GPM flow from nozzle = 250

For 2½” GPM = 250 FL = 2 (2.5)2 2 = 25

PDP = 50 + 25 = 75 psi

  1. What is the pump discharge pressure for supplying 100 feet of 1½” hoseline with a fog nozzle flowing 100 gpm?

For 1½” GPM = 100 FL = 24 (1)2 1 = 24

PDP = 100 + 24 = 124 psi

  1. What is the pump discharge pressure for supplying 200 feet of 1¾” hoseline with a fog nozzle flowing 150 gpm?

For 1¾” GPM = 150 FL = 15.5 (1.5)2 2 = 69.75

PDP = 100 + 69.75 = 169.75 or 170 psi

  1. What is the pump discharge pressure for supplying 250 feet of 2½” hoseline with a fog nozzle flowing 200 gpm?

For 2½” GPM = 200 FL = 2 (2)2 2.5 = 20

PDP = 100 + 20 = 120 psi

  1. A pumper is supplying a crew working on the third floor of a structure. The crew is using250 feet of 1¾” hoseline using a ⅞” smooth bore nozzle. What is the pump discharge pressure?

Flow from nozzle is 150 gpm

For 1¾” GPM = 150 FL = 15.5 (1.5)22.5 = 87.18 ≈ 87

NP = 50

EP = 5 (3-1) = 10

PDP = 50 + 87 + 10 = 147 psi

  1. A deluge set with a 1¼” straight tip is fed by one 3” hoseline400 feet long. What is the pump discharge pressure?

Flow from nozzle is 300 GPM

For 3” GPM = 300 FL = 0.8 (3)2 4 = 29

NP = 80

SA = 25 for deluge gun

PDP = 80 + 29 + 25 = 134 psi

GPM Solid Bore Nozzle
50psi / 80psi
⅞” / = / 150 gpm / 1⅜” / = / 400 gpm
1” / = / 200 gpm / 1½” / = / 600 gpm
1⅛” / = / 250 gpm / 1¾” / = / 800 gpm
1¼” / = / 300 gpm / 2” / = / 1000 gpm