What is "MVTR"?
MVTR stands for "Moisture Vapor Transmission Rate", a measure of the passage of gaseous H2O through a barrier. It's also know as "WVTR", or "Water Vapor Transmission Rate".
How is moisture resistance measured?
Moisture resistance is measured in a special chamber where it is divided vertically by the substrate/barrier material. A dry atmosphere is in one chamber, and a moist atmosphere is in the other. A 24-hour test is run to see how much moisture passes through the substrate/barrier from the "wet" chamber to the "dry" chamber. Standard test procedures (TAPPI T-464, ASTM E96) can specify any one of five combinations of temperature and humidity in the "wet" chamber. The toughest conditions are 100°F / 95%RH (Relative Humidity).
Currently, the best barrier material on the market today has an MVTR of .02. At Protective Packaging Corporation we focus on providing only the highest quality moisture barrier materials. With more than 25 years of experience in the field, we have the expertise to answer any of your questions. More importantly, our experience is what allows us to offer the most effective solutions, no matter the situation.