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You bet your glass: High exposure fenestration installation

“The standard contains a lot of very useful reference material that I could see myself looking for when working on a job.”

August 19, 2020  By Frank Fulton

To the casual observer, a window is just something you look through to see outside and there’s not a lot of thought given to it beyond that. For people involved in the application and installation of fenestration products, however, there are a mind-boggling number of intricate details that have to be considered and addressed. A slip-up or oversight on any one of them can result in leaks, condensation and mould, all of which are going to cost someone a lot of money to mitigate.

To provide a roadmap to follow from design concept through detailing, testing, installation, and final inspection, the Canadian Standards Association has recently released a new national standard entitled CSA A440.6:20 “High Exposure Fenestration Installation”. This standard applies to the installation of fenestration products in buildings of four or more stories in height of all occupancies, including residential punched and ribbon windows, window wall, curtainwall and storefront. According to the standard, “The users of this document include persons engaged in the design, selection and detailing of fenestration products and their installation into wall or roof assemblies; installers of fenestration products; specifiers of fenestration systems; technical staff of fenestration manufacturers engaged in designing fenestration systems; and persons and organizations that train fenestration installers.” I was very impressed by the amount of detail covered at every step of the process and with the illustrations provided to support the directions and recommendations.

“Improper installation of fenestration products can reduce their effectiveness, including causing excessive condensation, unacceptably high levels of air, water, and sound leakage, and deterioration of the wall and roof systems into which they are installed. This standard was developed to address issues that can adversely affect the performance of fenestration products when installed in building walls and roofs, and into both new and existing buildings subject to high environmental exposures.”

Besides outlining all the steps from start to finish of a window project, the standard also contains a lot of very useful reference material that I could see myself looking for when working on a job. There is a section on caulking that includes joint design size as a factor of temperature range expectations as well as a table identifying the sealants that are compatible with surrounding building materials. There are also good details on anchorage and recommended anchor types that vary by the substrate they are attaching to. The sections on treatments to ensure the continuity of the critical barriers – air, vapour, and water, were most informative.


Something I saw being addressed for the first time in this new standard was a forward-looking section on the effects of anticipated climate change and how it could impact fenestration product design and application. Changes in temperature, precipitation and humidity affect the level of various elements in the air, such as salt and pollution that could lead to accelerated degradation of some fenestration and building materials. The standard reviews climate data and tries to predict future weather based on four different models. This in turn is intended to be used when considering the performance requirements of the window products taking into consideration that the lifetime of a building will be 50 to 100 years.

From what I see in this new standard, I believe it won’t be long before it is being referenced in project specifications and being used by every design office. It will be in the hands of every consultant and quality assurance person on your jobsites. So, it wouldn’t be a bad idea to get a copy of it now to get ahead of the curve. I’m pretty sure you’ll find a lot of information that will help you a lot and can be put to immediate use on your projects.

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2 Comments » for You bet your glass: High exposure fenestration installation
  1. Avatar photo PL says:


    How and where can one test for whether the window is coated with Passive LowE or Solar Control Low E on windows?


  2. Avatar photo Frank Fulton says:

    Hello Lin and thank you for reading my column and for your question.
    There are Low-E Coating Detector electronic devices on the market that you might consider if you have to investigate Low-E coatings often, but a simpler and less expensive way is to hold up a candle or a pen light to the glass you want to assess. Insulating glass will give off four reflections. If one of the reflections is a different colour then one of the surfaces is coated with Low-E. If you want to read more, check this out from Vitro:

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