Convert Liters per Square Meter per Second to ft³/(ft²·min)

Formula

ft³/(ft²·min) = L/(m²·s) × 0.1968503937008

or ft³/(ft²·min) = L/(m²·s) ÷ 5.08

Derivation from SI units:

• 1 L/(m²·s) = 10⁻³ m³ ÷ (1 m² × 1 s) = 10⁻³ m/s = 1 mm/s
• 1 ft³/(ft²·min) = 0.3048³ m³ ÷ (0.3048² m² × 60 s) = 0.00508 m/s = 1 ft/min
• 1 L/(m²·s) = 0.001 m/s ÷ 0.00508 m/s per ft³/(ft²·min) = 0.1968503937008 ft³/(ft²·min)

Both units are defined exactly, so the factor is exact. Liter per Square Meter per Second definition: liter per square meter per second; CFM per Square Foot definition: cubic foot per square foot per minute.

Worked examples

1. A fabric at 100 L/(m²·s) (ISO 9237) is 19.68503937 ft³/(ft²·min).
   100 L/(m²·s) × 0.1968503937 = 19.68503937 ft³/(ft²·min)
2. 508 L/(m²·s) is exactly 100 ft³/(ft²·min).
   508 L/(m²·s) × 0.1968503937 = 100 ft³/(ft²·min)

Where it's used

European L/(m²·s) permeability values are converted to CFM/ft² for US customers and for comparison with ASTM D737 and Frazier results.

Liter per Square Meter per Second to other face velocity & air permeability units

Frequently asked questions

Sources

• ISO 9237:1995 Textiles — Determination of the permeability of fabrics to air, International Organization for Standardization , air permeability expressed per unit area.
• The International System of Units (SI), 9th edition (SI Brochure), Bureau International des Poids et Mesures , Table 8 (litre).
• 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: 2026-10-15. Factors are stored exactly and computed with 50-digit decimal arithmetic. See how we verify conversion factors.