An Automated Water Vapor Diffusion Test Method for Fabrics, Laminates, and Films

Abstract

An automated apparatus has been developed to measure the transport of water vapor through coated and uncoated fabrics, fabric laminates, thin foams, and solid films under a variety of conditions. The apparatus is more convenient to use than the traditional test methods for textiles and clothing materials; it allows one to use a wider variety of test conditions to investigate the concentration-dependent and nonlinear transport behavior of many of the semipermeable membrane laminates that are now available. The dynamic moisture permeation cell (DMPS) has been auto mated to permit multiple setpoint testing under computer control and to facilitate in vestigation of transient phenomena. Results generated with the DMPC are in agree ment with and of comparable accuracy to those from the ISO 11092 (sweating guarded hot plate) method of measuring water vapor permeability.