FGIA Updates Guidelines for Identification of Visual Obstructions in IGU Cavity Spaces

FGIA Updates Guidelines for Identification of Visual Obstructions in IGU Cavity Spaces
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FGIAonline.org

Date: 21 April 2026

Fenestration and Glazing Industry Alliance updates its guidelines to help the industry better identify and assess visual obstructions in insulating glass unit cavity spaces.

The Fenestration and Glazing Industry Alliance (FGIA) has released an advisory guideline intended for use by those who design, specify, fabricate and install insulating glass units (IGUs), as well as end-users in commercial buildings, residential properties and single-family homes. IGMA TM-3100-26, Voluntary Guidelines for the Identification of Visual Obstructions in the Cavity Space of Insulating Glass Units, an FGIA document, is now available for purchase in the FGIA online store. This document was last updated in 2009 and covers the visual obstruction guidelines for the cavity space of an IGU.

Visual obstructions are defined as anything located inside the IGU that unintentionally and materially obstructs a person’s view through the glazed daylight opening when inspected. These guidelines are provided as a service to the industry by FGIA, and reflect the collective experiences of IGU fabricators, glazing material suppliers, design engineers, and industry consultants. While not a specification, these guidelines should assist in the determination of unintended visual obstructions in the IGU cavity space.

“First created nearly two decades ago, FGIA’s IGMA TM-3100 guidelines have long served as the industry’s trusted standard for assessing visual obstructions in insulating glass,” said Dave Cooper (VacuumGlass), Vice Chair of the FGIA Visual Quality Guidelines Task Group. “It remains a widely referenced for evaluating visual obstructions and defines what is considered acceptable under recognized industry criteria.”

IGMA TM-3100-26, as well as other documents available from FGIA, may be purchased from the online store at the discounted member rate of $80 or the non-member price of $230.

For more information about FGIA and its activities, visit FGIAonline.org.

FGIA Updates Guidelines for Identification of Visual Obstructions in IGU Cavity Spaces

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