Maximum Recommended Air Flow (SCFM) Through ANSI Standard Weight Schedule 40 Metal Pipe - Technical Reference - Technical Literature - JGB Technical Information Center - JGB Enterprises, Inc.
The flow values in the table below are based on a pressure drop of 10% of the applied pressure per 100 feet of pipe for 1/8", 1/4", 3/8", and 1/2" pipe sizes; and a pressure drop of 5% of the applied pressure per 100 feet of pipe for 3/4", 1", 1-1/4", 2", 2-1/2", 3" pipe sizes.
The table gives recommended flows for pipe sizes at listed pressures and should be used to determine appropriate piping for air systems.
1/8" 1/4" 3/8" 1/2" 3/4" 1" 1-1/4" 1-1/2" 2" 2-1/2" 3"