©Copyright Task Force Tips, Inc. 2004 - 2017 LIU-330 November 16, 2017 Rev08
9
The following table shows the reference friction loss based on typical USA water fl ow/hose length/size. To calculate the back pressure,
add the nozzle pressure, hose friction loss, and elevation pressure loss together, and make sure the sum does not exceed 130 psi
(9 bar).
Eductor
Rating
Hose Size
Inch
3% - 6% Solution Up to 1% Solution
100 psi Nozzle 75 psi Nozzle 100 psi Nozzle 75 psi Nozzle
Maximum
Hose Lay Ft
Elevation
Ft
Maximum
Hose Lay Ft
Elevation
Ft
Maximum
Hose Lay Ft
Elevation
Ft
Maximum
Hose Lay Ft
Elevation
Ft
60 GPM
at
200 PSI
1.5 300 10 600 10 450 10 800 10
100 50 400 50 250 50 600 50
— — 150 100 — — 300 100
1.75 450 10 900 10 700 10 1200 10
150 50 600 50 400 50 900 50
— — 250 100 — — 500 100
2 950 10 1800 10 1300 10 2000 20
300 50 1200 50 750 50 1200 75
— — 500 100 50 100 750 100
95 GPM
at
200 PSI
1.5 100 10 200 10 150 10 300 10
— — 150 50 100 50 200 50
——————100100
1.75 200 10 350 10 300 10 450 10
— — 250 50 150 50 350 50
— — 100 100 — — 200 100
2 350 10 700 10 500 10 900 10
150 50 500 50 300 50 600 50
— — 150 100 — — 300 100
125 GPM
at
200 PSI
1.5 60 10 120 10 100 10 150 10
— — 80 50 50 50 100 50
——————50100
1.75 100 10 200 10 150 10 250 10
— — 150 50 100 50 200 50
——————100100
2 200 10 400 10 350 10 550 10
100 50 250 50 200 50 400 50
— — 100 100 — — 250 100
Similar charts can be created for eductors of other ratings and/or hoses of diff erent standard lengths and/or sizes. Friction loss will
also vary with the hose design and manufacturer, so it is important to know the characteristics of your hose.
5.0 MAXIMUM HOSE LAY
The maximum hose lay is based on the back pressure. Pushing the foam solution thru the hose and nozzle causes back pressure
on the eductor exit.
• On a 200 psi (13.8 bar) model, if the back pressure is over 130 psi (9 bar) the eductor will not work.
• On a 160 psi (11 bar) model, if the back pressure is over 100 psi (6.9 bar) the eductor will not work.
• On a 145 psi (10 bar) model, if the back pressure is over 95 psi (6.5 bar) the eductor will not work.
Elevation loss adds to the back pressure when the nozzle is higher than the eductor, e.g. 0.4 psi / foot and 0.1 bar / meter in vertical
height elevation loss.
WARNING
Do not exceed the allowable back pressure. Excess back pressure causes loss of foam fl ow
resulting in risk of injury or death from an ineff ective stream. Verify that adequate foam fl ow is
established and maintained.
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