FireHydraulics

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1. Fire Service Hydraulics (def)
The study and use of liquids in motion especially as pertaining to the use of water in the extinguishment and control of fire.
2. Hydrodynamics
Hydrostatics
• Hydrodynamics = Water in motion
• Hydrostatics= Water at rest

= Hydraulics
3. Fred Shepherd
First book on FS Hydrualics - 1917

Practical Hydraulics for Firemen
4. Nature of Water
• 1. abundant, cheap
• 2. chemically stable
• 3. absorbs heat 1120 btu/lb
• 4. virtually incompressable (30K psi for 1% volume reduction)
5. Fluid Pressure Principles
• 1. Perpendical to any surface
• 2. Same intensity in all directions
• 3. Pressure applied to confined pushes in all directions the same intensity (shape of container doesn't matter)
• 4. Pressure in open is proportional to the depth (.433 / ft)
• and density
6. Hydrualic Measurements of Water
• 1. 1 Gallon is 231 cubic inches
• 2. 1 Gallon weighs 8.34 lbs

• 1. 1 ft3 contains 1728 in3 (12x12x12)
• 2. Weighs 62.4 lbs
• 3. Contains 7.481 Gallons
7. Area Equations
• Squre or Rectangle LxW
• Triangle= 1/2 BH
• Circle= piR2 or .7854D2
8. Volume or Capacity
Container= LxWxH

Cylinder= .7854D2 x H
9. Back Pressure
• Pressure generated by the weight of a water column.
• .433/ft
10. Disharge
GPM flowing from an opening
11. Flow Pressure
• Forward velocity from a discharge port
• Usually measured with pitot guage
12. Friction Loss
Amount of engergy (pressure) lost in hose, applicance and turbulence.
13. Back pressure or Head Pressure
• H=2.304P (P=14.7 at sea level)
• P=.434H
• Rule of thumb- 5 psi per story
14. Atmospheric Pressure at sea level
• 14.7 psi
• 33.9 ft of water
• 30 in Hg
15. Number of feet water can be lifted
• 33.9 in perfect vacuum
• 25 ft for a good pump
• Rule of thumb is a little higher than vacuum guage reads.
16. Converstion of in.Hg. to feet
• Ft=1.13 x in.Hg.
• In.Hg=.885 x Ft
17. Velocity (ft/sec)
• The speed (ft/sec) that water travels from an orifice.
• Vaires inversly with the sqare of the orifice (double orifice, decrease velocity by 4)
18. Nozzle Range rule of thumb and formula
• 1 psi=1 ft range
• HR=NP/2+45
19. Discharge (def)
The volume of water in GPM from an orifice
20. Discharge volume (GPM) is function of:
• Diameter (squared) of orifice and
• Nozzle Pressure (squre root)
• GPM=29.7D2sqrtNP
21. Nozzle Reaction rule of thumb
NR= GPM/2 (half GPM)

• Varies by D2 and NP directly.
• Diameter means more than pressure.
22. Friction Loss general concepts
• Varies directly with length (2x length = 2x FL)
• Varies to the square of velocity (2x velocity = 4 x FL)
• Varies by inverse of D5 (greater diameter really decreases FL)
• FL varies by velocity not pressure
23. FL Formulas in use today
• CQ2xL=FL
• Q2x Multiplier x L=FL (constant Q)

Where Q=GPM/100 and L=Hoselenght/100

• Coefficients:
• 1 3/4: 15.5
• 2 1/2: 2
• 4: .2
• 5: .08
24. Discharge from Solid Bore at 50 PSI
• 1/2=53
• 5/8=81
• 7/8=161
• 1=210
• 1 1/8=265
• 1 1/4=326
25. Discharge from Solid Bore at 80 PSI
• 1 3/8=500
• 1 1/2=600
• 1 3/4=800
• 2=1000
26. Forestry Packs
• 100 PSI
• +10 PSI/100 ft @ 30 GPM
• 180-190 PSI
• Varies per apparatus and single or double discharges
28. Appliance FL
• None below 350 GPM
• >350= 10 PSI each, 25 PSI for Master Streams
29. Monitor FL
• 25 PSI at the base (FL for MS appliance)
• 80 PSI at the tip (master stream)
• =105 (~125 if "Monitor attack")
30. Standpipe FL
10-25 PSI depending on flow (25 is standard for calc)
31. Sprinkler System Pump Pressure
150 PSI at the pannel
32. Portable Monitor
• 1 3/8" 500 GPM 110 PSI + Supply line FL
• 1.5" 600 GPM 115 PSI + Supply line FL
• 1.75" 800 GPM 125 PSI + Supply line FL
33. Weight/gal of water in Hose and Tank
• 500/750 Gallon tank= 4170/6255 lbs
• 50' section of 4" = 32.6 gal
• 50' section of 5" = 51 gal
34. Formulas for Weight and Gallons in hose:
• .7854 x D2 x L in inches (volume of cylinder)
• divide by 231 cu in. per gallon= total gallons
• or
• 17 x D2 = Weight in 50 ft section
• (weight in 50)/8.33 (lbs per gallon)= total gal.

Card Set Information

 Author: dfrazier ID: 122347 Filename: FireHydraulics Updated: 2014-09-25 20:27:55 Tags: Fire Service Hydraulics Folders: Description: Fire Department Hydraulics for pumping Show Answers:

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