Search results
Results from the WOW.Com Content Network
Gases are compressible, which means that a figure in cubic feet per minute cannot necessarily be compared with another figure when it comes the mass of the gas. To further confuse the issue, a centrifugal fan is a constant CFM device or a constant volume device. This means that, provided the fan speed remains constant, a centrifugal fan will ...
Actual cubic feet per minute (ACFM) is a unit of volumetric flow. It is commonly used by manufacturers of blowers and compressors. [1] This is the actual gas delivery with reference to inlet conditions, whereas cubic foot per minute (CFM) is an unqualified term and should only be used in general and never accepted as a specific definition without explanation.
Air changes per hour, abbreviated ACPH or ACH, or air change rate is the number of times that the total air volume in a room or space is completely removed and replaced in an hour. If the air in the space is either uniform or perfectly mixed, air changes per hour is a measure of how many times the air within a defined space is replaced each hour.
Airflow can also be described in terms of air changes per hour (ACH), indicating full replacement of the volume of air filling the space in question. This unit is frequently used in the field of building science, with higher ACH values corresponding to leakier envelopes which are typical of older buildings that are less tightly sealed.
The clean air delivery rate (CADR) is a figure of merit that is the cubic feet per minute (CFM) of air that has had all the particles of a given size distribution removed. For air filters that have air flowing through them, it is the fraction of particles (of a particular size distribution) that have been removed from the air, multiplied by the ...
The SI unit is cubic metres per second (m 3 /s). Another unit used is standard cubic centimetres per minute (SCCM). In US customary units and imperial units, volumetric flow rate is often expressed as cubic feet per second (ft 3 /s) or gallons per minute (either US or imperial definitions).
References will be made to "actual" flow rate through a meter and "standard" or "base" flow rate through a meter with units such as acm/h (actual cubic meters per hour), sm 3 /sec (standard cubic meters per second), kscm/h (thousand standard cubic meters per hour), LFM (linear feet per minute), or MMSCFD (million standard cubic feet per day).
Typically, mass air flow measurements are expressed in the units of kilograms per second (kg/s) or feet per minute (fpm), which can be converted to volume measurements of cubic metres per second (cumecs) [1] or cubic feet per minute (cfm). [2]