SCFM is standard cubic feet per minute. It is at 68 degrees, 37% humidity.
It is usually used at the airflow into the compressor. Some use CFM for the
output. They can jiggle the temperature and humidity to make the numbers
appear a bit better too. SCFM sounds more honest.
The above is more like a definition of NTP (normal temperature/pressure
I think--unfortunately, there are also multiple definitions for it as
well as the multiple ways of measuring/reporting compressor performance.
To really have any idea, one needs to be able to find out the reference
conditions used even w/ SCFM labeling. :( The better the manufacturer
(read expensive like Ingersoll-Rand/Quincy/other industrial guys) the
more likely the results are trustworthy in comparison to the low-cost
But the CFM ratings generally are outputs--they'll be something like x
cfm @ y psi so that the pressure is given. Temperature generally isn't;
it's just whatever the output temperature of the air coming out the the
compressor is after the compressive cycle. So there's still that slight
variable even then altho unless the testing conditions are really
seriously manipulated one would presume that roughly the same size
compressors will have approximately same temperature rises and they
won't go to the trouble to run the test chamber input air from a grossly
refrigerated source to lower the temperatures artificially.
A reference to a bunch of various definitions that's kinda' handy...
Just don't forget to double the about of cfm/scfm the tool says it
needs-- and cut the cfm/scfm the compressor says it produces in half.
You can't go wrong that way.
They are ballpark and infinitely fudge-able numbers.
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