FireHydraulics
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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.

Hydrodynamics
Hydrostatics
 Hydrodynamics = Water in motion
 Hydrostatics= Water at rest
= Hydraulics

Fred Shepherd
First book on FS Hydrualics  1917
Practical Hydraulics for Firemen

Nature of Water
 1. abundant, cheap
 2. chemically stable
 3. absorbs heat 1120 btu/lb
 4. virtually incompressable (30K psi for 1% volume reduction)

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

Hydrualic Measurements of Water
 1. 1 Gallon is 231 cubic inches
 2. 1 Gallon weighs 8.34 lbs
 1. 1 ft^{3 }contains 1728 in^{3} (12x12x12)
 2. Weighs 62.4 lbs
 3. Contains 7.481 Gallons

Area Equations
 Squre or Rectangle LxW
 Triangle= 1/2 BH
 Circle= piR^{2} or .7854D^{2}

Volume or Capacity
Container= LxWxH
Cylinder= .7854D^{2} x H

Back Pressure
 AKA Head Pressure
 Pressure generated by the weight of a water column.
 .433/ft

Disharge
GPM flowing from an opening

Flow Pressure
 Forward velocity from a discharge port
 Usually measured with pitot guage

Friction Loss
Amount of engergy (pressure) lost in hose, applicance and turbulence.

Back pressure or Head Pressure
 H=2.304P (P=14.7 at sea level)
 P=.434H
 Rule of thumb 5 psi per story

Atmospheric Pressure at sea level
 14.7 psi
 33.9 ft of water
 30 in Hg

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.

Converstion of in.Hg. to feet
 Ft=1.13 x in.Hg.
 In.Hg=.885 x Ft

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)

Nozzle Range rule of thumb and formula
 1 psi=1 ft range
 HR=NP/2+45

Discharge (def)
The volume of water in GPM from an orifice

Discharge volume (GPM) is function of:
 Diameter (squared) of orifice and
 Nozzle Pressure (squre root)
 GPM=29.7D^{2}sqrtNP^{}

Nozzle Reaction rule of thumb
NR= GPM/2 (half GPM)
 Varies by D^{2 }and NP directly.
 Diameter means more than pressure.

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 D^{5} (greater diameter really decreases FL)
 FL varies by velocity not pressure

FL Formulas in use today
 CQ^{2}xL=FL
 Q^{2}x 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

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

Discharge from Solid Bore at 80 PSI
 1 3/8=500
 1 1/2=600
 1 3/4=800
 2=1000

Forestry Packs
 100 PSI
 +10 PSI/100 ft @ 30 GPM

Ladder Pipe
 180190 PSI
 Varies per apparatus and single or double discharges

Appliance FL
 None below 350 GPM
 >350= 10 PSI each, 25 PSI for Master Streams

Monitor FL
 25 PSI at the base (FL for MS appliance)
 80 PSI at the tip (master stream)
 =105 (~125 if "Monitor attack")

Standpipe FL
1025 PSI depending on flow (25 is standard for calc)

Sprinkler System Pump Pressure
150 PSI at the pannel

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

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

Formulas for Weight and Gallons in hose:
 .7854 x D^{2} x L in inches (volume of cylinder)
 divide by 231 cu in. per gallon= total gallons
 or
 17 x D^{2} = Weight in 50 ft section
 (weight in 50)/8.33 (lbs per gallon)= total gal.