What
is ACFM (Actual Cubic Feet per Minute)? What is SCFM (Standard Cubic Feet per Minute)? How
are they used? Both ACFM and SCFM are volumetric terms for
the amount of gas flowing through a pipe. Sponsler gas applications are sized to ACFM. In
most cases the customer requirements are stated in SCFM. ACFM and SCFM have a known
mathematical relationship expressed in the formula:
ACFM = SCFM x 14.7 / (14.7 + psig) x (460 + °F / 530)
To demonstrate, plug in the following values and work the math:
SCFM = 1000
psig = 100
°F = 70
ACFM = 1000 X .128 X 1
ACFM = 128
Assuming this is nominal flow in a pipeline, the Sponsler website
tools can be used to determine that the appropriate meter size for 128 ACFM is a 2"
meter that will give a linear measurement over a 15 – 250 ACFM flow range.
A good way to visualize this is remember that a
single ACFM can contain multiple SCFM, depending on the effects of pressure and
temperature.
