HydraulicsHydraulics

Theory and application allowing Theory and application allowing control and use of fluid pressurecontrol and use of fluid pressure

Hydraulic TheoriesHydraulic Theories

Understanding the theoretical and Understanding the theoretical and practical application of hydraulics essential practical application of hydraulics essential for pump operation. The study of fire for pump operation. The study of fire ground hydraulics is divided into two ground hydraulics is divided into two categories, theoretical and rule of thumb. categories, theoretical and rule of thumb. The driver/operator must be able to apply The driver/operator must be able to apply both.both.

Elements of Hydraulic Calculation Elements of Hydraulic Calculation

Nozzle Loss

Manifold/ Appliance

Attack Line Loss

Supply Line Loss

Elevation Loss

Standpipe Loss

Terminology in Friction Loss Terminology in Friction Loss FormulasFormulas

NP - NP - Nozzle PressureNozzle Pressure FL - FL - Friction LossFriction Loss AL - AL - Appliance LossAppliance Loss EL - EL - Elevation PressureElevation Pressure TPL - TPL - Total Pressure LossTotal Pressure Loss NPDP -NPDP - Net Pump Discharge Net Pump Discharge

PressurePressure

TheoreticalTheoretical In the classroom and non-emergency In the classroom and non-emergency

activities of the fire department, activities of the fire department, mathematical equations are used to mathematical equations are used to calculate the flow characteristics of our calculate the flow characteristics of our equipment and systems. This method of equipment and systems. This method of calculation is commonly referred to as calculation is commonly referred to as “Theoretical Hydraulics”. By using “Theoretical Hydraulics”. By using mathematical formulas, a relatively mathematical formulas, a relatively accurate calculation of the total probable accurate calculation of the total probable friction loss is obtained. This method is friction loss is obtained. This method is normally more accurate than Rule of normally more accurate than Rule of Thumb.Thumb.

Theoretical FormulaTheoretical Formula

There are many formulas and methods for There are many formulas and methods for figuring friction loss but the Renton Fire figuring friction loss but the Renton Fire Department has adopted the following for Department has adopted the following for use in its training program.use in its training program.

FL = CQFL = CQ22LL

WhereWhereQ = QuantityQ = QuantityC = CoefficientC = CoefficientL = Length in 100’sL = Length in 100’s

Coefficients for Renton Fire Department Coefficients for Renton Fire Department hose:hose:

1 ¾ “ 1 ¾ “ C = 15.5C = 15.5

2 ½ “2 ½ “ C = 2C = 2

3 ½ “ 3 ½ “ C = 0.34C = 0.34

5 “5 “ C = 0.08C = 0.08

Hose CoefficientsHose Coefficients

Siamesed Hose Lines CoefficientsSiamesed Hose Lines Coefficients

Two 2 ½” Two 2 ½” 0.50.5

Three 2 ½”Three 2 ½”0.220.22

Rule of ThumbRule of Thumb On the fire ground, the driver/operator On the fire ground, the driver/operator

normally works with a condensed and normally works with a condensed and simplified application known as “Rule of simplified application known as “Rule of Thumb Hydraulics”. Rule of thumb Thumb Hydraulics”. Rule of thumb hydraulic formulas are a chosen series of hydraulic formulas are a chosen series of fixed, rounded values that can be applied fixed, rounded values that can be applied to an operation sequentially to build a to an operation sequentially to build a water delivery system. water delivery system.

Rule of ThumbRule of Thumb

Fixed Rounded Value ExamplesFixed Rounded Value Examples

2 ½” Combination Nozzle 250 GPM

1 ¾” Combination Nozzle 125 GPM

1 ¾” Hose 25 psi FL / Section

2 ½” Hose 06 psi FL / Section

Master Stream Devices 25 psi FL

Appliances (Wye etc…) 0 FL @ <350 gpm

Appliances (Wye etc…) 10 psi FL @ > 350 gpm

Elevation 05 psi FL / Floor

Appliance Pressure LossAppliance Pressure Loss

< 350 gpm no calculated loss

> 350 gpm 10 psi per appliance

25 psi for all master stream devices

25 psi for all standpipes

Nozzles and TipsNozzles and Tips

Types of NozzlesTypes of Nozzles

Solid Stream Broken Stream

Periphery Deflected(Combination )

Impinging stream(Naval type)

Nozzle DesignNozzle Design

The purpose of any nozzle is to provide a restriction ofThe purpose of any nozzle is to provide a restriction ofthe flow to build pressure. This restriction, and subsequentthe flow to build pressure. This restriction, and subsequentcreated pressure, provides a usable velocity to project thecreated pressure, provides a usable velocity to project thewater stream. For any one flow, there is one correct nozzlewater stream. For any one flow, there is one correct nozzlesize (restriction) to develop the optimum pressure andsize (restriction) to develop the optimum pressure andvelocity. velocity.

Restriction

Designed Nozzle PressureDesigned Nozzle Pressure

Smooth Bore Nozzle - Hand line - 50 PSISmooth Bore Nozzle - Hand line - 50 PSI½” thru 1 ¼” nozzles½” thru 1 ¼” nozzles

Smooth Bore Nozzle - Master Stream - 80 PSISmooth Bore Nozzle - Master Stream - 80 PSInozzles 1 ¼” and overnozzles 1 ¼” and over

Fog Nozzle - 100 PSIFog Nozzle - 100 PSIall nozzlesall nozzles

Solid Stream - Solid Stream - CharacteristicsCharacteristics

The mechanical characteristics of a solid The mechanical characteristics of a solid stream nozzle produce a compact stream that stream nozzle produce a compact stream that has a higher mass and velocity. These features has a higher mass and velocity. These features typically yield better reach and penetration.typically yield better reach and penetration.

Solid Stream - Solid Stream - CompositionComposition

The interior diameter of the nozzle is gradually The interior diameter of the nozzle is gradually decreased until it reaches a point just short of decreased until it reaches a point just short of the outlet. At this point the straight cylindrical the outlet. At this point the straight cylindrical bore has a length from 1 to 1 ½ times its bore, bore has a length from 1 to 1 ½ times its bore, this area is known as the stream shaperthis area is known as the stream shaper

Solid Stream MechanicsSolid Stream Mechanics

Water flowing through a nozzle is subject to the same physical principals of friction as hose. The net effect of friction in a solid stream nozzle is the creation of a laminar flow. The center of the flowing stream is faster than the edge. This creates a peripheral turbulence that is visible after the stream exits the nozzle.

Discharge Volume:Discharge Volume: 29.7 x D29.7 x D2 2 x NPx NP

Nozzle Reaction:Nozzle Reaction: 1.57 x D1.57 x D2 2 x NPx NP

Solid Stream - FormulasSolid Stream - Formulas

Fog Stream - CharacteristicsFog Stream - Characteristics

A stream of water remains in a solid mass, not A stream of water remains in a solid mass, not losing continuity until it strikes an object, is losing continuity until it strikes an object, is overcome by gravity or is changed by friction overcome by gravity or is changed by friction with the air. Fog stream nozzles are designed with the air. Fog stream nozzles are designed around this theory and are commonly called around this theory and are commonly called broken stream appliances broken stream appliances

Fog Stream - CompositionFog Stream - Composition

All fog streams are of two mechanical All fog streams are of two mechanical types, Periphery-deflected or impinging types, Periphery-deflected or impinging stream. The shape and reach of a fog stream. The shape and reach of a fog stream are results of the appliance shape stream are results of the appliance shape and the velocity/pressure of the water. and the velocity/pressure of the water.

Impinging StreamImpinging Stream

Impinging Stream fog patterns are produced by driving jets of water together at a set angle to break the streams into finely divided particles. These appliances generally produce wide angle fog patterns.

Periphery-DeflectedPeriphery-Deflected

Periphery –Deflected streams are produced by deflecting water from the periphery of an inside circular stem to the inner circumference of the adjustable barrel. The position of the barrel varies the shape of the stream from a light fog to a straight stream. There are two common types of these nozzles, automatic and non-automatic.

Periphery-Deflected, Periphery-Deflected, AutomaticAutomatic

Automatic Periphery-Deflected nozzles have a spring loaded baffle assembly that reacts to incoming pressure. The baffle is calibrated to function at 100 PSI. The model illustrated has a sliding valve which allow the firefighter to meter the flow at the nozzle.

Periphery-Deflected, Periphery-Deflected, AutomaticAutomatic

When pressure at the When pressure at the nozzle is less, the baffle nozzle is less, the baffle moves in to maintain the moves in to maintain the pattern. When the pattern. When the pressure is greater than pressure is greater than 100 PSI the baffle moves 100 PSI the baffle moves out to allow more volume out to allow more volume and minimize the nozzle and minimize the nozzle reaction.reaction.

Periphery-Deflected, Periphery-Deflected, AutomaticAutomatic

Task Force Tip nozzles have a slide valve assembly that allows the water flow at the tip to be metered. By using this valve design, the nozzle has a smoother flow and less turbulence. Note the valve position in the illustrations.

Nozzle Reaction:Nozzle Reaction: 0.0505 x Q0.0505 x Q x NPx NP

Fog Stream - FormulasFog Stream - Formulas

Slide Valve OperationSlide Valve Operation

Slide Valve

Gated ½ Way

Ball Valve OperationBall Valve Operation

Ball Valve

Gated ½ Way

Nozzle reaction is the force that a firefighter feels when he is operating a nozzle. Nozzle reaction is primarily a result of discharge pressure at the nozzle. If the nozzle pressure is lowered, the firefighter will note a corresponding decrease in the nozzle reaction.

Nozzle ReactionNozzle Reaction To calculate the nozzle reaction use the following formulas, note same To calculate the nozzle reaction use the following formulas, note same flows can often be developed at a far lower nozzle reaction in solid flows can often be developed at a far lower nozzle reaction in solid stream nozzles. Traditional thought is that solid bore hand lines stream nozzles. Traditional thought is that solid bore hand lines should be pumped at 50 psi. Any nozzle pressures higher than 65 psi should be pumped at 50 psi. Any nozzle pressures higher than 65 psi becomes unmanageable. In the following table review and compare becomes unmanageable. In the following table review and compare the reaction force of various fire streams.the reaction force of various fire streams.

Nozzle Reaction: Nozzle Reaction: Solid StreamSolid Stream 1.57 x D1.57 x D2 2 x NPx NP

Nozzle Reaction: Nozzle Reaction: Fog StreamFog Stream0.0505 x Q0.0505 x Q x NPx NP

Handline Nozzle Reaction ChartHandline Nozzle Reaction Chart

125 GPM125 GPM3/4” tip @ 56 NP3/4” tip @ 56 NP == 49 NR49 NRcombination @ 100 NPcombination @ 100 NP == 63 NR63 NR

150 GPM150 GPM7/8” tip @ 44 NP7/8” tip @ 44 NP == 53 NR53 NRcombination @ 100 NPcombination @ 100 NP == 76 NR76 NR

175 GPM175 GPM7/8” tip @ 60 NP7/8” tip @ 60 NP = = 72 NR72 NRcombination @combination @ 100 NP100 NP == 88 NR88 NR

200 GPM200 GPM1” tip @ 46 NP1” tip @ 46 NP == 72 NR72 NRcombination @ 75 NPcombination @ 75 NP == 87 NR 87 NR combination @ 100 NPcombination @ 100 NP == 101 NR101 NR

250 GPM250 GPM1” tip @ 72 NP1” tip @ 72 NP == 113 NR113 NR1-1/8” tip @ 50 NP1-1/8” tip @ 50 NP = = 99 NR99 NRcombination @ 100 NPcombination @ 100 NP == 126 NR126 NR

300 GPM300 GPM 1” tip @ 100 NP1” tip @ 100 NP = = 157 NR157 NR1-1/8” @ 64 NP1-1/8” @ 64 NP = = 127 NR127 NRcombination @ 100 NPcombination @ 100 NP == 152 NR152 NR

325 GPM325 GPM 1” tip @ 120 NP1” tip @ 120 NP == 188 NR188 NR1-1/8” tip @ 75 NP1-1/8” tip @ 75 NP == 149 NR149 NR1-1/4” tip @ 50 NP1-1/4” tip @ 50 NP == 123 NR123 NRcombination @ 100 NPcombination @ 100 NP == 164 NR164 NR

Theoretical FormulaTheoretical Formula

FL = CQFL = CQ22LL

WhereWhere

Q = QuantityQ = Quantity

C = CoefficientC = Coefficient

L = Length in 100’sL = Length in 100’s

Coefficients for Renton Fire Department Coefficients for Renton Fire Department hose:hose:

1 ¾ “ 1 ¾ “ C = 15.5C = 15.5

2 ½ “2 ½ “ C = 2C = 2

3 ½ “ 3 ½ “ C = 0.34C = 0.34

5 “5 “ C = 0.08C = 0.08

Hose CoefficientsHose Coefficients

Siamesed Hose Lines CoefficientsSiamesed Hose Lines Coefficients

Two 2 ½” Two 2 ½” 0.50.5

Three 2 ½”Three 2 ½”0.220.22

2 2 ½” – 400 ‘½” – 400 ‘

1 ¾” – 150’1 ¾” – 150’

1 ¾” – 200’1 ¾” – 200’

125 gpm125 gpm

125 gpm125 gpm

AnswerAnswer

100 psi NP100 psi NP

48 psi FL 1 ¾”, 48 psi FL 1 ¾”, 200’200’

50 psi FL 2 ½”, 50 psi FL 2 ½”, 400’400’

198198 psi NPDP psi NPDP

(36 psi FL 1 ¾”, 150’ plus 5 psi (36 psi FL 1 ¾”, 150’ plus 5 psi elevation is less than 200’. Pump to elevation is less than 200’. Pump to the highest friction loss) the highest friction loss)

200’ of 5”200’ of 5”

200’ 1 ¾”200’ 1 ¾”

200 gpm200 gpm

250 gpm250 gpm

200’ 2 ½”200’ 2 ½”

AnswerAnswer

100 psi NP100 psi NP

5 psi elevation5 psi elevation

124 psi 1 ¾”, 200’124 psi 1 ¾”, 200’

10 psi appliance loss (>350gpm)10 psi appliance loss (>350gpm)

3.24 psi 5”, 200’3.24 psi 5”, 200’

242.24242.24 psi NPDP psi NPDP

(2 ½” FL is 25 psi, pump to the highest (2 ½” FL is 25 psi, pump to the highest loss) loss)

200’ of 5”

1 ½” tip1 ½” tip

2 ea. 2 ½” 50’

2 2 ½” 200’ 200’250 GPM250 GPM

600 GPM

AnswerAnswer

100 psi NP100 psi NP25 psi FL, 2 ½” 25 psi FL, 2 ½” 10 psi AL10 psi AL11.56 psi FL 5” 11.56 psi FL 5” 146.56146.56 psi NPDP psi NPDP

(NP 80 psi, 1 ½” tip 600 gpm / 25 psi FL (NP 80 psi, 1 ½” tip 600 gpm / 25 psi FL Masterstream / 9 psi FL 2 ½” Siamese Masterstream / 9 psi FL 2 ½” Siamese

= 114 psi. Pump to the highest loss. Gate = 114 psi. Pump to the highest loss. Gate down the Master stream if necessary)down the Master stream if necessary)

250’ 2 ½’ 250’ 2 ½’

1 ¼” 1 ¼”

Solid BoreSolid Bore

125 125 gpmgpm

250 gpm250 gpm1 ¾” 200’1 ¾” 200’

2 ½’” 200’ 2 ½’” 200’

200 gpm200 gpm1 ¾” 150’1 ¾” 150’

AnswerAnswer

2 ½”2 ½” 25 psi FL 25 psi FL

100 psi NP100 psi NP 1 ¾” 200 gpm, 93 psi FL 1 ¾” 200 gpm, 93 psi FL

1 ¾” 125 gpm, 48.4 psi FL1 ¾” 125 gpm, 48.4 psi FL

50 psi50 psi 2 ½” with 1 ¼” 328 gpm, 53.7 psi 2 ½” with 1 ¼” 328 gpm, 53.7 psi

193193 psi NPDP, pump to the psi NPDP, pump to the

highest friction losshighest friction loss

40’40’

150 gpm150 gpm

200’ 1 ¾”200’ 1 ¾”

AnswerAnswer

100 psi NP100 psi NP

17.36 psi EL (.434/ft)17.36 psi EL (.434/ft)

69.75 psi FL69.75 psi FL

187.11187.11 psi NPDP psi NPDP

100” Siamesed 2 ½”100” Siamesed 2 ½”

200’ 1 ¾” 150 gpm200’ 1 ¾” 150 gpm

Answer

100 psi NP @ 150 gpm69.75 psi FL 1 ¾”, 200’34.72 psi EL (.434 psi X 8 floors above the 1st)25 psi FL Standpipe01.125 psi FL Siamesed 2 ½”230.59 psi NPDP

100’ of 2 ½”100’ of 2 ½”

200’ of 1 ¾” @ 200 gpm

Answer

100 psi NP @ 150 gpm124 psi FL 1 ¾”, 200’34.72 psi EL (.434 psi X 8 floors above the 1st)25 psi FL Standpipe08 psi FL Siamesed 2 ½”291.72 psi NPDP

What single adjustment could you make to cut the friction loss by NPDP by 25 psi?

150’ of 2 ½” 150’ of 1 ¾”of 1 ¾”

150’ of 2 ½”

2 ea. / 100’ of 2 ½”2 ea. / 100’ of 2 ½”

250 GPM

180 GPM

Answer

100 psi NP @ 180 gpm75.33 psi FL 1 ¾”, 150’9.72 psi FL – 2 ½”, 150’26.04 psi EL (.434 psi X 6 floors above the 1st)25 psi FL Standpipe09.25 psi FL Siamesed 2 ½”245 psi NPDP

The 2 ½” NPDP was 187.72 pump to the highest friction loss. How would the excess pressure be dealt with in this line?