Evaluating air bag fabrics

Woven fabric have been the material of choice for air bag construction, but the questions have arisen concerning their performance at extreme temperature. The existing ASTM standard for measuring fabric permeability specifies an extremely low, 8.4-kPa pressure drop; a temperature of 21°C; and a controlled relative humidity of 65%. Because air bags are deployed under a range of conditions well outside the scope of this standard, there is need for a technique that examines actual performance characteristics. Hence, a 'blister inflation' technique has been developed that can simulate the actual conditions that air bags fabrics undergo, and can quantify pressure leaks through seams and energy dissipation through vents.