Millimeter per Second (mm/s)
The millimetre per second (mm/s) is one thousandth of a metre per second. It is the unit ISO 9237 uses for fabric air permeability, and 1 mm/s is exactly 1 L/(m²·s).
Symbol: mm/s
Quantity: face velocity and air permeability (volumetric flow per unit area)
SI relation: 1 mm/s = 0.001 m/s (exact)
Derivation: 1 mm/s = 0.001 m ÷ 1 s = 1 L/(m²·s)
Exact: yes, by definition
Same quantity as liter per square meter per second (L/(m²·s)) : the factor between them is exactly 1.
Typical uses
- Air permeability of fabrics, nonwovens and papers (ISO 9237, EN ISO 9237)
- Filter media and membrane specifications in Europe
- Low air speeds in cleanrooms and displacement ventilation
Convert millimeters per second to other units
Open the Face Velocity & Air Permeability Converter to convert any value between all units.
Sources
- The International System of Units (SI), 9th edition (SI Brochure), Bureau International des Poids et Mesures , Table 2 with SI prefix milli.
- ISO 9237:1995 Textiles — Determination of the permeability of fabrics to air, International Organization for Standardization , results expressed in mm/s.
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). Millimeter per Second (mm/s). Retrieved October 17, 2026, from https://scientificconverters.com/units/millimeter-per-second/
IEEE
Scientific Converters, "Millimeter per Second (mm/s)," scientificconverters.com. Accessed: Oct. 17, 2026. [Online]. Available: https://scientificconverters.com/units/millimeter-per-second/