CFM per Square Foot (ft³/(ft²·min))
The cubic foot per square foot per minute, ft³/(ft²·min) or "CFM per ft²", is the US air permeability unit (often called Frazier permeability). It is exactly 1 ft/min, 0.00508 m/s or 5.08 mm/s.
Symbol: ft³/(ft²·min) (ASCII: cfm/ft2)
Quantity: face velocity and air permeability (volumetric flow per unit area)
SI relation: 1 ft³/(ft²·min) = 0.00508 m/s (exact)
Derivation: 1 ft³/(ft²·min) = 0.3048³ m³ ÷ (0.3048² m² × 60 s) = 0.00508 m/s = 1 ft/min
Exact: yes, by definition
Same quantity as foot per minute (ft/min) : the factor between them is exactly 1.
History
The name comes from the Frazier differential-pressure air permeability tester, which reports CFM/ft² at 0.5 inH₂O (≈ 125 Pa), the pressure that ASTM D737 adopted.
Typical uses
- ASTM D737 fabric air permeability (inch-pound reporting)
- Filter media, felt and nonwoven datasheets in the US
- Paper-machine clothing and press felts
Convert cubic feet per square foot per minute to other units
Open the Face Velocity & Air Permeability Converter to convert any value between all units.
Sources
- ASTM D737 Standard Test Method for Air Permeability of Textile Fabrics, ASTM International , inch-pound results in ft³/min/ft².
- Guide for the Use of the International System of Units (SI), NIST Special Publication 811, 2008 Edition, National Institute of Standards and Technology , Appendix B.8, "foot per minute".
Last reviewed: . Factors are stored exactly and computed with 50-digit decimal arithmetic. See how we verify conversion factors.
Cite this page
APA
Scientific Converters. (2026, October 15). CFM per Square Foot (ft³/(ft²·min)). Retrieved October 17, 2026, from https://scientificconverters.com/units/cubic-foot-per-square-foot-per-minute/
IEEE
Scientific Converters, "CFM per Square Foot (ft³/(ft²·min))," scientificconverters.com. Accessed: Oct. 17, 2026. [Online]. Available: https://scientificconverters.com/units/cubic-foot-per-square-foot-per-minute/