Glass Canada

IGMA – December 2017

Guidance you can trust

November 29, 2017  By Margaret Webb

The beat of ever-improving energy efficiency in our fabricated glass products goes on, driven by concerns about climate change and initiatives like the Paris Climate Accords. In a world where Canadian builders soon may not be allowed to install fenestration with anything less than an R8 insulating factor, adhering to the highest standards of quality and technology has become critical for everyone in our industry.

To help, the Insulating Glass Manufacturers Alliance publishes guidelines that provide a foundation for high-quality IGU manufacture, drawing on the expertise of dozens of North America’s top fabricators that has been accumulated over a century of insulating glass manufacturing.

Today we take a look at “Glazing Guidelines for Sealed Insulating Glass Units for Commercial and Residential Use.” These are advisory guidelines to assist in achieving long-term performance of sealed insulating glass units. They are intended for use by those who design, specify, manufacture and install insulating glass units and were written as a result of open discussions and review by the IGMA Glazing Guidelines Working Group, which reports to the IGMA Technical Services Committee. These guidelines have been developed in accordance with IGMA quality control and due process procedures to help assure their reasonableness. They reflect existing technology and are subject to periodic review and change.

IGMA understands that what is applicable in residential glazing does not necessarily apply to commercial glazing and vice versa. Section 5.0, Setting Blocks, is one section that underwent significant modifications over the two pre-existing documents, now covering both residential and commercial applications. To ensure compatibility and consistency between fenestration industry standards and specifications, this section was developed in consultation with members of the American Architectural Manufacturers Association and the Window and Door Manufacturers Association, who were developing the harmonized “AAMA/WDMA/CSA 101/I.S.2/A440 – Standard/Specification for Windows, Doors, and Unit Skylights.” The most significant addition is the positioning of setting blocks for triple-glazed IGUs.

Section 3.0, Framing, and Section 4.0, Glazing Clearances, are other examples that are more comprehensive and include both commercial and residential applications. The original guidelines did not differentiate between residential and commercial units, though in some circumstances one may overlap the other and users of the guidelines should recognize the differences. References to commercial applications include the AAMA’s “Aluminum Curtain Wall Design Guide Manual.” The latest version of the guidelines includes diagrams and charts and that now provide the user with information on both commercial and residential applications. For instance, separate charts lay out the different recommendations for edge clearances on larger IGUs for residential use versus commercial use.

These guidelines are provided as a service to the industry by the IGMA and reflect the collective experiences of insulating glass manufacturers, glass and glazing material suppliers, design engineers, industry consultants and persons and firms experienced in successful glazing techniques. Although not a specification, these guidelines should assist in the successful glazing and performance of sealed insulating glass units. They are not intended to exclude other possible glazing practices. These guidelines reflect those that have been associated over the years with successful field performance of sealed insulating glass units. Users are encouraged to seek professional advice for specific glazing applications that differ from those detailed in these guidelines. Compliance with all local governing building codes is also required.

Copies of this and other IGMA publications can be ordered by visiting the IGMA website ( or by contacting the office at 613-233-1510. •

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