Pressure drop in a 100 ft pipe with compressed air entering at 100 psig can be found in the table below:

Pressure drop in 100 ft pipe (psi)

Free Air Inflow Volume Flow at Standard Conditions  (SCFM) 1)

Nominal Pipe Size - schedule 40 (inch)

3/4 1 1 1/4 2 2 1/2 3 4 6

40 1.2 0.4            

70 3.8 1.1 0.1          

90 6.0 1.7 0.2          

100 7.5 2.1 0.2          

400   32.2 3.6 1.0 0.4 0.1    

1,000     22.0 5.9 2.4 0.8 0.2  

4,000           11.9 2.9 0.4

7,000             8.8 1.1

10,000             18.0 2.1

40,000               33.8

1) It is common to rate the compressed air consumption in Standard Cubic Feet per Minute - SCFM

The SCFM - Standard Cubic Feet per Minute - determines the weight of air to fixed or "Standard" conditions. There are several definitions of SCFM. The most common used in the United States is with properties:

14.696 Pounds per Square Inch (psia) 60 Degrees Fahrenheit (oF) 0% Relative Humidity (RH).

Europeans normally use one ATA and 0oC as SCFM