What is the recommended CFM at 90 PSI for various pipe sizes?

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SUMMARY

The recommended maximum CFM for compressed air at 90 PSI through various pipe sizes is as follows: 1/2" pipe can handle 74 SCFM, 1" pipe 295 SCFM, 1.25" pipe 608 SCFM, 1.5" pipe 912 SCFM, and 3" pipe 4946 SCFM. These values assume a clean, schedule 40, steel pipe and a pressure drop of 2 PSI per 10 feet of pipe. The actual flow rate can vary significantly based on system specifics, including pipe length, fittings, and material type. For precise calculations, users are encouraged to utilize online pressure drop calculators.

PREREQUISITES
  • Understanding of SCFM (Standard Cubic Feet per Minute) measurements
  • Knowledge of pipe sizing and types, specifically schedule 40 steel pipe
  • Familiarity with pressure drop concepts in fluid dynamics
  • Basic skills in using online calculators for pressure drop analysis
NEXT STEPS
  • Research how to calculate pressure drop in compressed air systems
  • Explore online pressure drop calculators for practical applications
  • Learn about different pipe materials and their impact on airflow
  • Investigate the effects of fittings, elbows, and valves on air pressure
USEFUL FOR

This discussion is beneficial for engineers, HVAC professionals, and anyone involved in designing or optimizing compressed air systems, particularly those focused on airflow efficiency and pressure management.

mapair
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Hello folks, I am trying to find some general numbers on what the recommended max. CFM for compressed air @ 90 PSI is through the following pipe sizes: 1/2", 1", 1.25", 1.5" & 3". I'm not looking for anything specific, just some general numbers. I'd greatly appreciate any input on this! Thanks!
 
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Hi mapair,
I wouldn't recommend a maximum flow through a pipe because it varies so much depending on the actual system and what the system is needed for. The longer the pipe, and the more elbows, valves and other restrictions it has, the more pressure drop you will get. What might be an acceptable flow rate for one system may produce way too much pressure drop for another system.

Just to give you a few numbers for flow (note: all flow is in SCFM, assuming 70 F) I'll jot down some flows that give you a 2 psi drop per 10 feet of pipe. I'm also assuming clean, schedule 40, steel pipe for each of these:
1/2" - 74 SCFM
1" - 295 SCFM
1.25" - 608 SCFM
1.5" - 912 SCFM
3" - 4946 SCFM

If you want more specific calculations, you might try doing a search for free online calculators.
http://www.google.com/search?hl=en&q=pressure+drop+calculator+free&safe=active

or just be more specific about what you have in your system and I'll throw it into my calculator.
 
The material and construction technique are probably your most serious considerations. Glued-together ABS will not be in the same universe with welded stainless.
 

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