Codes and standard requirements, pertaining to installing fenestration products, were highlighted in a seminar during the annual conference of the Fenestration and Glazing Industry Alliance (FGIA). Robert Jutras, principal engineer for UL/CLEB, led the presentation on the requirements and focused on CSA A440.4, a National Standard of Canada covering window, door and skylight installation, according to the alliance.

“The standard we are focusing on today is specific to the Canadian National Building Code (NBC),” said Jutras.

NBC Part 9, dedicated to housing and small buildings, covers windows and doors and products that are factory assembled, he said. New information has been included in it since its creation; a 2019 fourth edition includes an appendix discussing how to halt the impact of climate change.

“Let’s look at sub-sill flashing,” Jutras said. “Where does it need to be installed?”

It is required in some places based on climate conditions, he said, explaining that this is defined by a moisture index and building exposure nomograph. The exposure nomograph method for fine tuning the moisture index and the basis for determining where sub-sill flashing was required can be found in CSA-A440.4-07, Annex A, according to Jutras.

The ‘Building Exposure Nomograph’ allows fine-tuning of installation requirements to take into account building, orientation and micro-climate effects, said Jutras. Drawing a line from the overhang ratio for the building, based on site measurements, to the appropriate terrain type will cross the three colored bars in the middle, corresponding to three ranges of moisture index. Choose the appropriate moisture index for the location of the building, he noted. The 2019 fourth edition of CSA A440.4 will likely be referenced in NBC-2020 in Part 9.

“The scope has a reduced focus similar to the 1998 version,” he said. “It’s now applicable to windows, doors and skylights compliant with [the North American Fenestration Standard]. This version also includes climate change resiliency.”

When it comes to mandatory sub-sill flashing, Jutras offered some advice.

“With combination/mulled window installation, even though you did the best job possible, protect the bottom [of the product],” he said.

A user’s guide is in the works for this standard, to be published by 2025, Jutras added.

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