Test Background
Water vapor transmission rate actually includes two meanings: water vapor transmission amount and water vapor transmission coefficient. The meanings expressed by these two meanings are also somewhat different, but they can both be used to express the ability of water vapor to penetrate a certain material.
The water vapor transmission rate indicates the weight of water vapor permeable through the material under certain conditions of temperature and humidity at a certain time. Water vapor transmission rate is the standard value of water vapor transmission amount converted by coefficient, and corresponds to the standard unit, which is used for comparison between different test results.
Zhongke Testing Reliability Experiment Center has the capabilities of environmental testing and reliability performance testing of various building materials, products and components, and provides professional water vapor transmission performance testing services for building materials and products.
Scope of tests
Various plastic films, plastic composite films, paper-plastic composite films, geomembranes, co-extruded films, waterproof breathable films, aluminized films, aluminum foil, aluminum foil composite films and other film materials.
Test method
The test piece is sealed on the opening of the test cup filled with desiccant (dry method) or saturated solution (wet method) to form a test assembly, and then placed in a temperature and humidity controlled test studio.
Due to the difference in the partial pressure of water vapor in the test cup and the test chamber, the wet flow of water vapor will flow through the test piece. The steady-state wet flow rate of water vapor can be determined by periodically weighing the mass of the test assembly.
Test standard:
ISO 12572: 2001 Hygrothermal properties of building materials and their products - Determination of water vapor transmission properties
GB/T 17146-2015 Test method for water vapor transmission performance of building materials and their products
GB/T 20312-2006 Hygrothermal properties of building materials and products: Determination of hygroscopic properties
GB/T 20313 Hygrothermal properties of building materials and products: Determination of moisture content Drying method
