What does ACFM mean in Unit Measures?

Actual cubic feet per minute

Actual cubic feet per minute is a unit of volumetric capacity. It is commonly used by manufacturers of blowers and compressors. This is the actual gas delivery with reference to inlet conditions, whereas cubic foot per minute is an unqualified term and should only be used in general and never accepted as a specific definition without explanation. Since the volumetric capacity refers to the volume of air or other gas at the inlet to the unit, it is often referred to as "inlet cubic feet per minute". Actual cubic feet per minute is the volume of gas flowing anywhere in a system independent of its density. If the system were moving air at exactly the "standard" condition, then ACFM would equal Standard cubic feet per minute. However, this usually is not the case as the most important change between these two definitions is the pressure. To move air, either a positive pressure or a vacuum must be created. When positive pressure is applied to a standard cubic foot of air or other gas, it gets smaller. When a vacuum is applied to a standard cubic foot of gas, it expands. The volume of gas after it is pressurized or rarefied is referred to as its "actual" volume.

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