WATER VAPOR TRANSMISSION RATE OF PAPER AND PAPERBOARD AT HIGH TEMPERATURE AND HUMIDITY

This method is for the gravimetric determination of the water vapor transmission rate (WVTR) of sheet materials at 37.8°C (100°F) with an atmosphere of 90% RH on one side and a desiccant on the other.

It is generally suitable for any material up to 3 mm (1/8 in.) thick, although it may be used with caution for thicker materials if the edges of the specimen are completely sealed.

For testing at other conditions see TAPPI T 448 “Water Vapor Transmission Rate of Paper and Paperboard at 23°C (73°F) and at 50% RH.”

This test can be used for both creased and uncreased specimens. See TAPPI T 465 “Static Creasing of Paper for WVT Tests” or TAPPI UM 590 “Creasing of Paperboard for Water Vapor Transmission Rate (WVTR) Testing.”