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Air Flow Schedule

PSI drop per 100′ length of pipe

Select your pipe diameter from below and use the tables to determine the Pounds Per Square Inch drop per 100 feet of schedule 40 steel pipe. As a general rule of thumb, the higher the initial Line Pressure (PSIG), the lower the pressure loss per length of pipe.

For lengths other than 100 feet, the pressure drop is directly proportional to the ratio of difference in lengths.

Example:

  • 200′ Pipe would result in a pressure drop of 2x the value seen in table.
  • 25′ Pipe would result in a pressure drop of one-quarter the value seen in table.

The table below shows the airflow pressure drop in Pounds per Square Inch per 100 feet of schedule 40 pipe.

FOR EXAMPLE, if Bob has a line pressure of 80 PSIG with an airflow of 6 SCFM moving through the 100 feet of pipe, he would experience a drop in pressure of approximately 12.85 Pounds per Square Inch.

Line Pressure (PSIG)Free Air (SCFM)
2468
402.7510.1022.2039.00
602.007.4016.2528.55
801.605.8512.8522.55
1000.354.8510.6018.60

The table below shows the airflow pressure drop in Pounds per Square Inch per 100 feet of schedule 40 pipe.

FOR EXAMPLE, if Jory has a line pressure of 100 PSIG with an airflow of 15 SCFM moving through the 100 feet of pipe, he would experience a drop in pressure of approximately 13 Pounds per Square Inch.

Line Pressure (PSIG)Free Air (SCFM)
5101520
403.3012.5027.2547.80
602.409.1520.0035.00
801.907.2015.7527.60
1001.605.9513.0022.80

The table below shows the airflow pressure drop in Pounds per Square Inch per 100 feet of schedule 40 pipe.

FOR EXAMPLE, if Peter has a line pressure of 60 PSIG with an airflow of 10 SCFM moving through the 100 feet of pipe, he would experience a drop in pressure of approximately 1.95 Pounds per Square Inch.

Line Pressure (PSIG)Free Air (SCFM)
510152025303540
400.702.654.7010.0015.4022.0029.8038.60
600.551.953.407.3011.2516.1021.8028.25
800.401.502.705.758.9012.7017.2022.30
1000.351.252.254.757.3510.5014.2018.40

The table below shows the airflow pressure drop in Pounds per Square Inch per 100 feet of schedule 40 pipe.

FOR EXAMPLE, if James has a line pressure of 80 PSIG with an airflow of 30 SCFM moving through the 100 feet of pipe, he would experience a drop in pressure of approximately 3.80 Pounds per Square Inch.

Line Pressure (PSIG)Free Air (SCFM)
1020304050608090
400.703.006.6011.5017.8025.6044.9056.60
600.552.204.858.4013.0018.7532.8541.45
800.451.753.806.6510.3014.7525.9032.70
1000.401.553.456.009.3013.3523.4029.55

The table below shows the airflow pressure drop in Pounds per Square Inch per 100 feet of schedule 40 pipe.

FOR EXAMPLE, if Lisa has a line pressure of 80 PSIG with an airflow of 175 SCFM moving through the 100 feet of pipe, she would experience a drop in pressure of approximately 23 Pounds per Square Inch.

Line Pressure (PSIG)Free Air (SCFM)
2040608090100125150175
400.722.725.9710.3713.1016.1224.9535.6048.40
600.522.004.377.609.5911.8018.2526.0035.45
800.411.563.456.007.559.3011.4020.5527.95
1000.341.292.824.956.227.6511.8516.9523.00

The table below shows the airflow pressure drop in Pounds per Square Inch per 100 feet of schedule 40 pipe.

FOR EXAMPLE, if Joe has a line pressure of 80 PSIG with an airflow of 150 SCFM moving through the 100 feet of pipe, he would experience a drop in pressure of approximately 5.88 Pounds per Square Inch.

Line Pressure (PSIG)Free Air (SCFM)
50100150200250275300325350
401.204.6310.2017.9027.8633.5039.8246.7554.00
600.873.387.4513.1020.4024.5029.1534.2039.60
800.682.655.8810.3216.1019.3523.0027.0031.22
1000.572.204.858.5013.1015.9318.9522.2858.77