What Is SCFM on an Air Compressor?by Karren Doll Tolliver
SCFM, an acronym that stands for standard cubic feet per minute, is a specification that indicates the volume of air an air compressor can provide at a certain pressure.
According to The Air Compressor Exchange of Perrysburg, Ohio, the amount of air taken into a compressor from the outside is indicated by CFM, or cubic feet per minute.
CFM can vary with humidity, temperature and atmospheric pressure. Therefore, another measurement is necessary to give an indication of air compressor output. That measurement is SCFM.
SCFM is calculated as CFM at sea level, at a temperature of 68 degrees Fahrenheit and with 36 percent relative humidity.
How SCFM is Written
Listings for SCFM are presented at specific pressures expressed in pounds per square inch (psi). For example, an SCFM rating might be written as 3.0 SCFM at 90 psi. Of course, if the psi is reduced, the SCFM rating will increase. The inverse is also true; if pressure goes up, SCFM will decrease.
In a practical example, if a job requires an airflow of 450 SCFM, an air compressor that has a CFM of 450 may not be sufficient if the atmospheric pressure, temperature or humidity varies much from the standards.
- photo_camera Image by Flickr.com, courtesy of Hey Paul