From motor type and tank size, to piston configurations and fuel, air compressors offer a variety of sizes and variants for different applications and industrial processes. Besides these variations, you may find two different measures for the compressed air output mentioned for air compressors: Standard Cubic Feet per Minute (SCF) or Cubic Feet per Minute (CFM). The experts at Trident Compressor Air explain the key difference between SCFM and CFM and what it means for your business.
Understanding Volumetric Flow Rate and Mass Flow Rate
- CFM: Measures the volume of air that the air compressor delivers to your pneumatic tools. In this measure, the temperature and pressure components are variable. Essentially, volumetric flow rate in CFM indicates the air flow rate measured for actual conditions, i.e. actual temperature, and actual pressure. However, air density will change with temperature and pressure, which is where a more scientific calculation, such as SCFM comes in handy.
- SCFM: Measures the gas’ volume flow rate, but in a controlled environment, with known pressure, temperature, and relative humidity. Typically, North American manufacturers define it as 14.5 PSIA or 14.696 PSIA, 60°F or 68°F, and 36% or 0% relative humidity. However, the standard set of reference conditions may vary across continents, as there is no clear consensus on a ‘world standard’. These standardized conditions give way to mass flow rate, i.e. measurement of the mass of a thing or substance that travels through a certain surface in a specific unit of time.
The CFM rating of an air compressor will always be lower than its SCFM rating, because most manufacturers measure the CFM at a point where the air pressure is lower or equal to 90 PSI. For an appropriate comparison between different compressors, it is better to use SCFM rating instead of the CFM rating, because in SCFM, all the measurements are calculated back to a set of standard conditions.
Get Expert Help for Your Compressed Air System Requirements
Building or upgrading compressed air systems can be a complex process. From calculating the total CFM or SCFM, to choosing the right air compressors and accessories, every step requires technical expertise and precision. For optimum results and accurate calculations, count on the certified and experienced technicians at Trident Compressed Air LTD. We are committed to providing quality products, tailor-made solutions, and unparalleled customer service to help you maximize your investment in compressed air systems.
Need help in determining the mass flow, volumetric flow, or other specifications for installing or expanding your compressed air systems? Please contact our office at (519) 737-9905 or fill out our online form. Our service department is on call 24 hours a day and we are eager to help answer any questions or concerns you may have about your equipment.