FGIA updates specification giving design considerations for multiple-cavity insulating glass units
Posted on February 2nd, 2026
The Fenestration and Glazing Industry Alliance (FGIA) has released an updated specification offering guidelines intended to identify design considerations to be taken into account when designing multiple-cavity insulating glass units (IGUs) and the evaluation of the manufacturing process, as well as addressing the quality requirements of the sealed space of a multiple-cavity IGU. IGMA TM-1300-26, Design Considerations for Multiple-Cavity Insulating Glass Units, an FGIA document, is now available for purchase in the FGIA online store. This document was last updated in 2013.
The purpose of this document is to guide the design, fabrication and use of multiple-cavity IGUs within the fenestration industry.
“Demand for increasing energy-efficient fenestration products continues to rise,” said Amy Becker, FGIA Glass Products Specialist, and staff liaison for the FGIA Design Considerations for Multiple Cavity IGUs Task Group. “One method for addressing this demand is by increasing the number of cavities in an insulating glass unit. This method, while effective, can create new challenges. These guidelines are therefore intended to assist those who design, specify, fabricate and install units.”
IGMA TM-1300-26, as well as other documents available from FGIA, may be purchased from the online store at the discounted member rate of US$80 or the nonmember price of US$230. For more information about glazing guidelines, consider purchasing a copy of IGMA TM-3000, North American Glazing Guidelines for Sealed Insulating Glass Units for Commercial & Residential Use.
For more information about FGIA and its activities, visit FGIAonline.org.
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