Field Hydraulics I

Information and slides provided by RFD

Objectives

Overview of hydraulic worksheet

Apply FL for hose lines using worksheet

Apply NP, ELV +/-, and AppFL using worksheet.

Calculate Pump Discharge Pressure using Worksheet.

Field Hydraulics Sheet

Purpose of the field hydraulic sheet is

to assist Operators with a quick

calculation for fire ground operations.

The calculations are close, but not

100% accurate compared to classroom

formulas.

Pump Discharge Pressure What is Pump Discharge pressure?

“Actual velocity pressure (measured in pounds per

square inch) of water as it leaves the pump and enters

the hoseline.”

IFSTA Pumping Apparatus Driver/Operator Handbook 1st. Ed., page 460

PDP = 150 psi

0 psi

Net Pump Discharge Pressure

What is Net Discharge Pump Pressure?

“Actual amount of pressure being produced by the

pump. When taking water from a hydrant, it is the

difference between the intake pressure and the

discharge pressure.” IFSTA Pumping Apparatus Driver/Operator Handbook 1st. Ed., page 458

50 psi

NPDP = 100 psi

PDP = 150 psi

Net Pump Discharge Pressure (Cont..)

(NPDP) Hydrant pressure left unattended will increase your

PDP beyond the ability of the crew to manage the

hose.

PDP = 200 psi 50 psi

NPDP = 150 psi “Ahhh, reduce

your RPM”

“Ahhh, why

didn’t you set

your relief

valve?”

Field Hydraulic Worksheet

Review Excel Work Sheet

Field Hydraulics Sheet

Start with NP

Fill in the field Hydraulics table.

Determine the pressure control setting.

Remember the intake/hydrant pressure

Field Hydraulics Sheet PDP = 200ft 1 ¾ 75 PSI AND 100 PSI

FOG nozzles.

145 psi PDP = 150 gpm

170 psi PDP = 150 gpm

75

70

145

100

70

170

Liveline Drill # 1

Figure hydrant pressure

at 60 psi.

200 feet of

1 3/4” hose.

150 GPM

Automatic nozzle.

Figure hydrant pressure

at 60 psi.

200 feet of

1 3/4” hose

125 GPM.

Low pressure

Automatic nozzle.

75 psi NP

Photo from “Fire Service Hydraulics” E.F. Mahoney

Answers Drill # 1

200 ft 1 ¾ hose, flowing 150 GPM, with 100 PSI fog nozzle.

NP = 100 PSI

ELV = 0

AppFl = 0

FL for 200 ft 1 ¾ = 70 PSI

PDP = 170 PSI

NPDP = 110 PSI

Answers Drill # 1

200 ft 1 ¾ hose, flowing 125 GPM, with 75 PSI fog nozzle.

NP = 75 PSI

ELV = 0

AppFl = 0

FL for 200 ft 1 ¾ = 50 PSI

PDP = 125 PSI

NPDP = 65 PSI

Handline 2 ½ Drill # 1

What is the PDP = ?

Find the NPDP if the hydrant pressure is 50 psi.

Photo from “Fire Service Hydraulics” E.F. Mahoney

Answers 2 ½ Drill # 1

Use the Hydraulic sheet to plug in what we know.

NP = 45 PSI

ELV = 0

AppFl = 0

Figure out the GPM of 1 inch tip at 45 PSI =200

GPM

FL for 600 ft 2 ½ @ 200 GPM = 48 PSI

PDP = 93 PSI

NPDP = 43 PSI

2 ½ Handline Drill 2

400’ of 2 1/2” attack hose

Find the PDP for this semi-truck roll-over

fire. Use an 1 1/4” tip at 45 psi NP (you

make the call).

1 1/4” tip

at 45 psi NP 40 ft

Elevation gain

Photo from “Fire Service Hydraulics” E.F. Mahoney

Find the NPDP for a hydrant pressure of 75 psi.

Answers 2 ½ Drill # 2

NP = 45 PSI

ELV +/- = -20

AppFl = 0

Figure out the GPM of 1 1/4 inch tip at 45 PSI =300 GPM

FL for 400 ft 2 ½ @ 200 GPM = 72 PSI

PDP = 97 PSI

NPDP = 25 PSI

Answers 2 ½ Drill # 2 (Cont..)

What would you do in this situation?

Engage pump and gate down line.

Just flow from the hydrant?

You make the call.

Last one

Photo from “Fire Service Hydraulics” E.F. Mahoney

Hydrant pressure is 75 psi.

100’ of 3” hose

100’ of 1 3/4” hose

150 GPM

100 psi nozzles

100 psi nozzles

100’ of 1 3/4”

hose

150 GPM

Answer to the Last One

NP = 100 PSI

ELV +/- = 0

Figure out total GPM of both 1 ¾ lines flowing 150 GPM each = 300 GPM

AppFl = 0 total flow < 350 GPM

FL 1 3/4 = 35 PSI Only have to figure FL for one line because they are the same length, diameter, and

nozzle pressure IFSTA Chapt. 8 pg. 151

FL for 3 inch= 7 PSI

PDP = 142 PSI

NPDP = 67 PSI

Take A Break

Field Hydraulics

Multiple Lines 1 3/4” 200 ft liveline with a

100 psi fog nozzle @ 150 GPM

200’ of 2 1/2” with a Smoothbore & 1” Tip

A Wye Set-up with 200’ of 3” supply hose to 2 100 ft 1 ¾ lines flowing 125 gpm each with 75 psi fog nozzles.

Field Hydraulics

Multiple Lines 1 3/4” 200 ft liveline with a

55 psi TFT dual force @ 150 GPM

200’ of 2 1/2” with a Smoothbore & 1” Tip

A Wye Set-up with 200’ of 3” supply hose to 2 100 ft 1 ¾ lines flowing 125 gpm each with 100 psi fog nozzles.

Hydrant 70 PSI

Liveline Smooth Set-up

100

70

170

45

16

61

100

25

10

135

135

100

High Rise

Follow departments Sop’s for

FDC assignments

Elevation Pressure (+ or -)

IFSTA calls it “EP” we call it “Elv.”

Pressure is directly proportional to height of container (hose or pipe).

To much confusion with engine pressure EP and elevation pressure EP.

Classroom Formula:

P = .434 x Head/height

Field Formula:

1/2 psi per foot

1/2 H (Height)

High-rise

5 psi per floor

Elevation Pressure Formulas

Elv = 1/2 H (+ or -)

High-rise

5 psi per floor

MGM Fire

Las Vegas, Nev.

Elv = 1/2 H

High Rise

100’ of 1 3/4” attack hose with 100 psi fog, @ 150 gpm

100’ of 2 1/2”” hose from the class 1 standpipe

to your attack line

Two- 3” supply lines,

50’ long.

Remember: Only

count FL for the

standpipe if GPM

exceeds 350

Figure for

a 60 psi

hydrant Photo from “Fire Service Hydraulics” E.F. Mahoney

Answer to High Rise question

100

+ 25

0

35

5 0

165

165

165- 60 105

High Rise Multiple lines

100’ of 2 1/2”

With 1 1/8 tip

100’ of 2 ½ with 100 psi fog

flowing 200 gpm

Three 3” lines 100’ to the FDC.

Figure the Hydrant at 75 psi.

Answers Multiple Lines

Smooth Fog

45 100

+ 30 +20

25 25

12 8

2 2

114 137

137

137 - 75 62

High Rise

As an Operator what are you going to advise the

Firefighters on the 7th floor.

They will have to gate down the pressure.

At the Standpipe

Or at the bale (That is what I would recommend.)

Why? Possibility of more lines attached to FDC

which will take water and pressure away from you.

You don’t want to travel back to the standpipe

unless you have too.

Friction Loss (FL)

Defined on page 456

Principles of Friction Loss pages 114 to 116.

IFSTA “Pumping Apparatus

Driver/Operator Handbook”

Appliance Friction Loss (AppFL)

IFSTA: . >350 gpm, figure for AppFL

Handline evolutions:

Wye/Siamese/Gate >350 gpm = 10psi

Standpipes >350 gpm = 25psi+

Eductors are 50 psi AppFL

Finding FL in Hose

(CQ2L)

IFSTA Pumping Apparatus Driver

Handbook

pages 142 to 164.

Quick Look at the Formula

FL= CQ2L

C= coefficient for diameter of hose

Q2=

L = GPM

100

) ( 2

Length of Hose

100

Coefficients and Q2

15.5

Take a Break