Testing & Quality Control

Air Permeability & Fabric Porosity Calculator

Porosity is a volume fraction; permeability is a flow rate. High porosity does not guarantee high flow.

Permeability Test At test pressure
L/m²/s
Pa
Fabric For porosity
g/m²
mm
g/cm3

Air Permeability

— CFM

Cubic feet per square foot per minute

Structure & Flow

Volumetric Porosity
— %
Fabric Bulk Density
— g/cm3
Air Velocity through Fabric
— m/s
Flow per Unit Pressure
— L/m²/s/Pa

Always quote the test pressure alongside the reading. A permeability figure without its pressure drop cannot be compared with anything.

Air Permeability & Fabric Porosity Calculator — free, with the formula and a worked example, at Textile School.