These charts can help you with some of the daily calculations a pressure washer professional must deal with.
Formulas | Boiling Point | Hose Friction | Pipe Friction
Nozzle Chart | Natural Gas Supply | Fuel Nozzle | Horse Power Requirements
Saturated Water Substance
(Boiling point of water at various pressures)
P.S.I. (psia) |
Temperature °f |
30 | 250 |
100 | 327 |
500 | 467 |
3000 | 695 |
Diesel Fuel Nozzle Chart
(SC & HP Series with standard Hydro Tek coil)
GPM | 140° rise | 150° rise | BTU |
2 | 1.00 70° B | 1.00 70° B | 172,000 |
2.5 | 1.75 80° B | 1.75 80° B | 250,000 |
3 | 1.75 80° B | 1.75 80° B | 275,000 |
4 | 2.50 80° A | 2.50 80° A | 365,000 |
5 | 3.00 90° B | 3.00 90° B | 435,000 |
6 | 3.50 90° B | 3.50 90° B | 500,000 |
Nozzle size x 140000= diesel fired BTU @ 100 psi fuel pressure.
°C=.555 (°F - 32) | °F=1.8(°C )+ 32
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Horse Power Requirements (Minimum)
Electric HP = (psi x gpm) / 1460 Gas Engine HP = (psi x gpm) / 1100
Pressure | Flow | Cleaning Units | Electric HP | Gas Engine HP |
1000 | 2 | 2000 | 1.36 | 1.81 |
3 | 3000 | 2.05 | 2.75 | |
4 | 4000 | 2.74 | 3.65 | |
1200 | 2 | 2400 | 1.64 | 2.18 |
2.5 | 3000 | 2.05 | 2.74 | |
3 | 3600 | 2.46 | 3.28 | |
4 | 4800 | 3.28 | 4.37 | |
1500 | 2 | 3000 | 2.05 | 2.73 |
3 | 4500 | 3.08 | 4.1 | |
4 | 6000 | 4.1 | 5.46 | |
2000 | 3 | 6000 | 4.1 | 5.46 |
4 | 8000 | 5.47 | 7.29 | |
5 | 10000 | 6.84 | 9.12 | |
2500 | 3 | 7500 | 5.13 | 6.84 |
4 | 10000 | 6.84 | 9.12 | |
5 | 12500 | 8.56 | 11.41 | |
3000 | 4 | 12000 | 6.16 | 8.21 |
5 | 15000 | 10.27 | 13.69 | |
6 | 18000 | 12.32 | 16.42 | |
10 | 30000 | 20.54 | 27.39 | |
3500 | 4 | 14000 | 8.22 | 10.96 |
4.5 | 15750 | 10.78 | 14.39 | |
5 | 17500 | 11.99 | 15.98 | |
6 | 21000 | 14.38 | 19.18 | |
4000 | 4 | 16000 | 10.95 | 14.6 |
4.5 | 18000 | 12.33 | 16.44 | |
5 | 20000 | 13.69 | 18.25 | |
5000 | 4.5 | 22500 | 15.41 | 20.54 |
Length of run | Pipe Diameter |
0-50 ft | 1 1/4" |
51-150 ft | 1 1/2" |
151 - 500 ft | 2" |
Please consult your local gas company for relevant building and safety codes for your area
Nozzle Size | Orifice Dia. | 500 psi | 700 psi | 1000 psi | 1200 psi | 1500 psi | 2000 psi | 3000 psi | 3500 psi | 4000 psi | 5000 psi |
2 | 0.034 | 0.71 | 0.80 | 1.00 | 1.10 | 1.20 | 1.40 | 1.70 | 1.90 | 2.00 | 2.30 |
3 | 0.043 | 1.05 | 1.35 | 1.50 | 1.60 | 1.90 | 2.10 | 2.60 | 2.85 | 3.00 | 3.30 |
3.5 | 0.045 | 1.20 | 1.43 | 1.75 | 1.90 | 2.10 | 2.50 | 2.90 | 3.30 | 3.50 | 3.90 |
4 | 0.052 | 1.40 | 1.70 | 2.00 | 2.20 | 2.50 | 2.80 | 3.50 | 3.80 | 4.00 | 4.50 |
4.5 | 0.055 | 1.50 | 1.90 | 2.20 | 2.40 | 2.80 | 3.00 | 3.90 | 4.30 | 4.50 | 5.00 |
5 | 0.057 | 1.80 | 2.10 | 2.50 | 2.80 | 3.10 | 3.60 | 4.40 | 4.70 | 5.00 | 5.60 |
5.5 | 0.060 | 1.90 | 2.30 | 2.80 | 3.00 | 3.40 | 3.80 | 4.80 | 5.20 | 5.50 | 6.20 |
6 | 0.062 | 2.10 | 2.50 | 3.00 | 3.20 | 3.70 | 4.20 | 5.20 | 5.60 | 6.00 | 6.80 |
6.5 | 0.064 | 2.30 | 2.70 | 3.30 | 3.60 | 4.00 | 4.60 | 5.70 | 6.00 | 6.50 | 7.30 |
7 | 0.067 | 2.50 | 2.90 | 3.50 | 3.80 | 4.30 | 5.00 | 6.10 | 6.60 | 7.00 | 7.90 |
7.5 | 0.070 | 2.70 | 3.20 | 3.80 | 4.10 | 4.60 | 5.30 | 6.50 | 7.00 | 7.50 | 8.40 |
8 | 0.072 | 2.80 | 3.40 | 4.00 | 4.40 | 5.00 | 5.60 | 7.00 | 7.50 | 8.00 | 9.00 |
8.5 | 0.074 | 3.00 | 3.60 | 4.30 | 4.60 | 5.30 | 6.00 | 7.40 | 8.00 | 8.50 | 9.60 |
9 | 0.076 | 3.20 | 3.80 | 4.50 | 5.00 | 5.50 | 6.40 | 7.80 | 8.50 | 9.00 | 10.10 |
8.5 | 0.078 | 3.40 | 4.00 | 4.80 | 5.20 | 5.80 | 6.80 | 8.30 | 9.00 | 9.50 | 10.60 |
10 | 0.080 | 3.50 | 4.20 | 5.00 | 5.40 | 6.10 | 7.00 | 8.70 | 9.40 | 10.00 | 10.20 |
12 | 0.087 | 4.20 | 5.00 | 6.00 | 6.40 | 7.30 | 8.40 | 10.30 | 11.20 | 12.00 | 13.60 |
15 | 0.094 | 5.30 | 6.30 | 7.50 | 8.20 | 9.20 | 10.60 | 12.90 | 14.00 | 15.00 | 16.80 |
Pipe Friction Loss
Pressure Loss in coils in PSI (aprox.)
GPM | Diesel Fired | Natural Gas |
2 | 6 | 11 |
3 | 13 | 23 |
4 | 24 | 43 |
5 | 34 | 61.2 |
Hose Friction Loss
Pressure loss in 3/8" id hose (aprox.)
Length in feet | 2 gpm | 3 gpm | 4 gpm | 5 gpm | 6 gpm | 7 gpm |
100 | 25 | 50 | 90 | 130 | 220 | 300 |
200 | 50 | 100 | 180 | 260 | 440 | 600 |
300 | 75 | 150 | 270 | 390 | 660 | 900 |
Handy Formulas: |
Water Weight = Pounds = Gallons x 8.3453 |
Liters = Gallons x 3.785 |
Gallons = Liters x .2642 |
bar = psi x .069 |
psi = bar x 14.5 |
psi = 4000 x (gpm / nozzle #) |
gpm = Nozzle # / (psi / 4000) |
psi = In. HG x .4912 |
In HG = In H2O x .07355 |
Cubic Inches = Gallons x 231 |