User Manual
7
Piping Loss Calculation for Wall Mount Self Cleaning System
To ensure proper operation of the Self Cleaning System, a minimum operating water pressure rating, see
Table 1, during spraying must be achieved at the hood nozzles. For this to occur, proper sizing of the
water line is required. Use the following steps to calculate the piping minimum size.
1. Use the Minimum Pressure Requirements for Lengths of Hood chart and find the Self
Cleaning minimum PSI required at the hood inlet. Subtract this value from the available PSI at
the panel pressure gauge. Maximum panel operating pressure is 50 psi. This will be your
maximum allowable pressure drop for field installed pipes between the panel and the hood.
2. Most fittings add an equivalent pipe length to the total run. Use the chart below to calculate the
equivalent pipe length for installed fittings. If you have multiple fittings of one type, simply multiply
the number below by the total number of the fitting and add to the total run length.
Equivalent Pipe Length For Various Pipe Fittings
Pipe Size Inches
45° Elbow
90° Elbow
Tee Thru Run
Tee Thru Branch
3/4"
0.97
2.10
1.40
4.10
1"
1.23
2.60
1.80
5.30
1 ½"
1.90
4.00
2.70
8.00
2"
2.40
5.20
3.50
10.40
3. To calculate the total flowing pressure drop between the panel and the hood, take the total
equivalent length found in step 2 and add the total linear field installed pipe length. Multiply this
number by the value found in the table below, Pressure Drop (PSI) per Equivalent Foot of
Waterline. (Gallons per minute is calculated by multiplying the length of the hood by 0.7 gpm)
This will be the friction pressure drop between the hood and the panel.
4. Add in the pressure drop due to
gravity. This must be evaluated to
overcome any rise in pipe elevation
between the panel and the hood.
There is .43 psi/ft of vertical rise of
pressure drop.
5. Now, compare the maximum
allowable pressure drop from step 1 to
the calculated pressure drop from
step 3. If the calculated pressure drop
exceeds the maximum allowable
pressure drop, increase the pipe size
and recalculate steps 2 and 3.
Continue this step until the calculated
pressure drop is below the maximum
allowable.
Pressure Drop (PSI) per Equivalent Foot of Waterline
- Pipe Size
Gallons per
Minute
Waterline Pipe Size (psi per foot of
pipe)
3/4”
1”
1 1/2”
2”
5
0.028
0.008
0.001
0.000
10
0.102
0.029
0.004
0.001
15
0.216
0.062
0.008
0.001
20
0.368
0.105
0.014
0.002
25
0.556
0.159
0.022
0.003
30
0.779
0.223
0.030
0.004
35
1.036
0.296
0.040
0.006
40
1.327
0.379
0.052
0.008
45
1.650
0.472
0.064
0.009
50
2.005
0.573
0.078
0.011
55
2.391
0.684
0.093
0.014
60
2.809
0.803
0.110
0.016
65
3.257
0.931
0.127
0.019
70
3.736
1.068
0.146
0.021
75
4.244
1.213
0.166
0.024
80
4.782
1.367
0.187
0.027
85
5.350
1.529
0.209
0.030
90
5.946
1.700
0.232
0.034
95
6.572
1.879
0.256
0.037
100
7.226
2.066
0.282
0.041
105
7.909
2.261
0.309
0.045