Canadian Consulting Engineer

Standardizing MVTR testing and reporting for IGUs

April 28, 2023

window condensation

Photo courtesy FGIA.

The Fenestration and Glazing Industry Alliance (FGIA) has released a new technical bulletin, IGMA TB-2701-23, Guidelines for the Testing of Moisture Vapor Transmission Rate (MVTR) and the Presentation of the Results.

The document provides a standardized test method, sample configuration and units for reporting purposes for the transmission rate of moisture vapour pertaining to insulating glass units (IGUs). Based on updated American Society for Testing and Materials (ASTM) methods and their relevance to IGU testing, FGIA decided to adopt ASTM F1249, Standard Test Method for Water Vapor Transmission Rate Through Plastic Film and Sheeting Using a Modulated Infrared Sensor, as the standard method for evaluating sealant MVTR.

“This document helps modernize the methods that fenestration professionals can use to test the rate of moisture permeation across IGU edge sealants,” explains Brian White, chair of FGIA’s relevant 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.”

IGMA TB-2701-23 is available from FGIA’s online store.


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