ASTM International Committee F02 on Flexible Barrier Packaging is developing a new standard to test the transmission rate of water vapor into packaging materials, which is a key component for the shelf life of many products. Proposed standard WK49124, Test Method for Water Vapor Transmission Rate through Packages Using a Modulated Infrared Sensor, is based on another ASTM standard, F1249, that measures water vapor through plastic film and sheeting with pressure modulated infrared detector.