Vacuum pipes - air velocity diagrams
Air velocities in vacuum pipes can be estimated with the diagrams below.
Standard and Actual Air Volume - cfm
The diagram is calculated for steel pipes schedule 40.
Example - Estimating the Vacuum Air Flow Velocity
Velocity in a NPS 3" steel pipe with standard air volume flow 100 scfm at 30% vacuum can be estimated to approximately 3000 fpm as indicated in the diagram below: