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Fire Ground Hydraulics. Fire Ground Hydraulics? 120? 150? 175? 200? P.S.I.? GPM? Loss per 100 ft.? Hose Diameter? Elevation Loss? Device Loss? Pump Pressure?

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Presentation on theme: "Fire Ground Hydraulics. Fire Ground Hydraulics? 120? 150? 175? 200? P.S.I.? GPM? Loss per 100 ft.? Hose Diameter? Elevation Loss? Device Loss? Pump Pressure?"— Presentation transcript:

1 Fire Ground Hydraulics

2 Fire Ground Hydraulics? 120? 150? 175? 200? P.S.I.? GPM? Loss per 100 ft.? Hose Diameter? Elevation Loss? Device Loss? Pump Pressure? Nozzle pressure?

3 Fire Ground Hydraulics Pump Discharge Pressure equals Nozzle Pressure + (Total Pressure Loss) Pump Discharge Pressure equals Nozzle Pressure + (Total Pressure Loss) PDP = NP+(FL+DL+EL) NP = Nozzle Pressure FL = Friction Loss DL = Device Loss EL = Elevation Loss PDP = NP+(FL+DL+EL) NP = Nozzle Pressure FL = Friction Loss DL = Device Loss EL = Elevation Loss Single, Selectable Gallonage, & Automatic

4 Friction Loss Hoseline Friction Loss FL = CQ 2 L FL = Hoseline friction loss in PSI C = Friction loss coefficient* Q = Flow rate in hundreds of GPM (GPM/100) L = Hose length in hundreds of feet (Feet/100) * Refer to NFPA Fire Protection Handbook Hoseline Friction Loss FL = CQ 2 L FL = Hoseline friction loss in PSI C = Friction loss coefficient* Q = Flow rate in hundreds of GPM (GPM/100) L = Hose length in hundreds of feet (Feet/100) * Refer to NFPA Fire Protection Handbook

5 Hose Friction Loss (per 100 feet of hose)

6 Elevation Pressure Loss Device Loss Elevation Pressure EP = 0.5H 0.5 = A constant H = Height in feet Device Loss Appliance Friction loss in PSI Elevation Pressure EP = 0.5H 0.5 = A constant H = Height in feet Device Loss Appliance Friction loss in PSI

7 Calculating for Pump Discharge Pressure Selectable or Single Gallonage or Automatic 125 gpm at 100 psi NP on 150 ft. of 1¾” hose PDP = NP+TPL TPL = FL = CQ 2 L TPL = (15.5)(1.25) 2 (1.5) TPL = 36 PDP = PDP = 136 PDP = NP+TPL TPL = FL = CQ 2 L TPL = (15.5)(1.25) 2 (1.5) TPL = 36 PDP = PDP = 136

8 Calculating for Pump Discharge Pressure Selectable (Change Flow Setting) or Automatic 150 gpm at 100 psi NP on 150 ft. of 1¾” hose PDP = NP+TPL TPL = FL = CQ 2 L TPL = (15.5)(1.5) 2 (1.5) TPL = 52 PDP = PDP = 152 PDP = NP+TPL TPL = FL = CQ 2 L TPL = (15.5)(1.5) 2 (1.5) TPL = 52 PDP = PDP = 152

9 Calculating for Pump Discharge Pressure Master Stream 1½” Smooth Bore Tip PDP = NP+TPL TPL = FL+DL TPL = CQ 2 L+Device Loss FL = (.677)(5.98) 2 (3) = 73 DL = 25 TPL = = 98 PDP = PDP = 178 PDP = NP+TPL TPL = FL+DL TPL = CQ 2 L+Device Loss FL = (.677)(5.98) 2 (3) = 73 DL = 25 TPL = = 98 PDP = PDP = psi NP on 300 ft. of 3” hose

10 Hoseline Friction Loss  Coefficients from NFPA Fire Protection Handbook  Manufacture, construction, age & condition of hose are determining factors  Actual coefficients of friction can be determined  Test your hose for actual coefficients  Refer to IFSTA Fire Streams Manual for procedures  Coefficients from NFPA Fire Protection Handbook  Manufacture, construction, age & condition of hose are determining factors  Actual coefficients of friction can be determined  Test your hose for actual coefficients  Refer to IFSTA Fire Streams Manual for procedures

11 Single & Selectable Nozzles  Pump pressure charts can be made for any hose lay  Hydraulic calculations can be pre-planned  Communication is key to safe operations  When operated at correct pressures, they will deliver the stated flow  For multiple lines of different size, flow &/or length, pump to the maximum required pressure & gate the other discharge valves to correct pressure for each line  Pump pressure charts can be made for any hose lay  Hydraulic calculations can be pre-planned  Communication is key to safe operations  When operated at correct pressures, they will deliver the stated flow  For multiple lines of different size, flow &/or length, pump to the maximum required pressure & gate the other discharge valves to correct pressure for each line

12 Automatic Nozzles  Hydraulic calculations are simpler  Nozzle pressure remains constant (typically 100psi)  If calculations are incorrect, automatic nozzles will deliver the available flow  Maximum reach with available water  As nozzles are throttled, pump operator should avoid “chasing” the pressure gauge  The goal should be to maintain the minimum pressure necessary for the line  Hydraulic calculations are simpler  Nozzle pressure remains constant (typically 100psi)  If calculations are incorrect, automatic nozzles will deliver the available flow  Maximum reach with available water  As nozzles are throttled, pump operator should avoid “chasing” the pressure gauge  The goal should be to maintain the minimum pressure necessary for the line


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