The Fenestration and Glazing Industry Alliance (FGIA) has released a new technical bulletin (IGMA TB-2701-23) providing a standardized testing method and sample configurations and units for reporting the transmission rate of moisture vapor pertaining to insulated glass units (IGUs).

Based on updated ASTM test methods available and their relevance to IGU testing, it was decided to adopt ASTM F1249 as the standard test method for evaluating sealant Moisture Vapor Transmission Rates (MVTR).

“This document helps modernize the methods that fenestration professionals can use to test the rate of moisture permeation across IGU edge sealants,” said Brian White, chair of the FGIA MVTR update task group. “Knowing the MVTR of a particular sealant is critical to choosing the best barrier to moisture ingress and ensuring the longest possible IGU service life.”

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