The difference between static and dynamic pressure on a compressor’s pressure gauge.
Static pressure is the reading before you start the air flowing. Dynamic pressure is the the reading after you start air flowing. Because the dynamic pressure is always lower it’s called a pressure drop.
The size of the drop depends on the size and length of the airhose you’re using.
Pressure drop is more important the bigger your air system is. The more people, stations, and equipment you use off of one system the more important it is to know that you’re getting the right amount of air to any one station to do the required job.
|1/4 Inch Inner Diameter Air Hose|
|@ 40 PSI||8||9.5||11||12.75||24|
|@ 50 PSI||10||12||14||16||28|
|@ 60 PSI||12.5||14.5||16.75||19||31|
|@ 70 PSI||14.5||17||19.5||22.5||34|
|@ 80 PSI||16.5||19.5||22.5||25.5||37|
|@ 90 PSI||18.75||22||25.25||29||39.5|
|5/16 Inch Inner Diameter Air Hose|
|@ 40 PSI||2.75||3.25||3.5||4||8.5|
|@ 50 PSI||3.5||4||4.5||5||10|
|@ 60 PSI||4.5||5||5.5||6||11.5|
|@ 70 PSI||5.25||6||6.75||7.25||13|
|@ 80 PSI||6.25||7||8||8.75||14.5|
|@ 90 PSI||7.5||8.5||9.5||10.5||16|
*Note: I totally lifted this chart wholesale from the Anest-Iwata pressure drop chart.