Leadership

Questions & Answers

Issue 1 and Volume 116.

Questions & Answers Nozzle Operating Lower than Pumper To the Editor: A pumper on a bridge is operating at 100 psi supplying a 1 1/8-inch nozzle, 150 feet vertically below at the river’s edge, through 800 feet of 2 1/2-inch hose. What is the nozzle pressure? W. T. C. Answer: Since the nozzle is below the pumper, head pressure of 150 feet x .434 pounds per foot, or 65.1 psi, must be added to the engine pressure. Corrected , engine pressure is therefore 65.1 plus 100 or 165.1 psi (see page 87 Fire Service Hydraulics). N. P. = E. P. / (1.1 + KL) E. P. = 165.1 K for 2 1/2-inch hose and 1 1/8-inch nozzle is .167 L is 800 / 50, or 16 Then: N. P. = 165.1 / [1.1 + (.167 x 16)] = 165.1 / [1.1 + 2.672] = 165.1 3.772 = 44.3 Finding Effective…

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