When choosing among different models of air compressors, people compare their technical characteristics in order to understand which one would better cope with planned tasks. It is unclear to many buyers what acronyms CFM and SCFM mean and what is the difference. This article is to give you the idea of these parameters and how they may influence the productivity of your device.
CFM means cubic feet / minute. It is the main throughput characteristic of an air compressor that is determined for a specific pressure – PSI (pounds per / inch).
You should understand that this parameter is rather of a theoretical than practical nature. Use it to compare different devices but do not expect them to work just like stated. You may get disappointed if your air tool overheats, loses speed due to abrasion, gaps between construction elements, and other factors impairing productivity. Be ready for the fact that the actual picture always will be somewhat different.
CFR has long been used to determine planned throughput of air tools until engineers agreed on a new, more reliable and accurate indicator – SCFM (standard CFM). The peculiarities of environment and operations performed are now taken into account.
Let’s say atmospheric pressure is expected to be 14.7 pounds / square inch, temperature – 65°F, and humidity – 0%. We can calculate SCFM for this particular state and be sure that the planned air stream would be generated. If we deviate from this state, SCFM should be adjusted respectively. If the pressure decreases, less air is available for compression and throughput is lower. The same happens if the temperature grows. Much moisture is in the air makes it more challenging for a compressor to process vapor that turns into water.
All these nuances should be kept in mind if you want to derive SCFM from CFM or vice versa.
The tip for those going to buy a compressor: if you know your planned throughput, choose CFM that is at least 1.5 times higher to make sure that your device would work in any conditions.