Since the air density of an air flow stated at standard conditions (SCFM) is always the same, it is essentially a mass flow rate! Stating an air flow in units of SCFM makes it easy to compare conditions, and certain calculations simpler. When the ideal gas law is rearranged, the air density can be seen to be proportional to pressure, and inversely proportional to temperature.Īir density at standard conditions =. As you may remember, density = mass/volume.

This can be seen from taking a look at the ideal gas law. The distinction between SCFM and CFM is important because air density will change with pressure and temperature. 3/minute at standard conditions (1 atm = 14.7psi, 68☏ ) Why do that?Ī volumetric flow rate with units of CFM implies that the flow rate was measured at actual conditions (actual pressure, actual temperature). Standard Cubic Feet per Minute = SCFM = ft. Different industries and standard organizations actually cite slightly different values for what standard conditions are, but we are going to save that discussion for another time.Ĭubic Feet per Minute = CFM = ft.

For the sake of this discussion, we are going to assume standard conditions of 1 atm and 68☏. SCFM is an acronym for Standard Cubic Feet per Minute, with “Standard” implying standard conditions. Whether it is supplied by a fan, blower, or compressed air line, the volumetric air flow rate is simply stating the volume of air passing through over a given unit of time. In the US, it is very common to see the volumetric air flow rate stated in units of Cubic Feet per Minute. We are going to concentrate on the first question. How hot does the air have to get? In other words, what is the temperature rise required?.How much “stuff” do we have to heat up? In more technical terms, what is the mass flow rate?.When determining the power required to heat a stream of air, invariably two questions will come up. The majority of Tutco–Farnam Custom Product’s heaters are used to heat an air flow.

Convert cfm airflow to mass flow rate