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Interpreting the Word 'OR' in BC's Building Code

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Windows and Doors have been exposed to the NAFS standard since 2012. As time has passed, we have seen a few code changes and alterations in the code language that is used around NAFS.

Most of this was designed to clarify the intent of how NAFS should be used to be code compliant, as there was a fair bit of confusion when it was first introduced. I want to shed light on a very important word that can get overlooked from time to time in determining if a window is code compliant or not.  

The word I am referring to is "OR"

9.7.4. Design and Construction

  1. Except as provided by Sentence (2), windows, doors, skylights and their components shall be designed and constructed in accordance with

A)Article, or

B)Part 5.

  1. Windows, doors, skylights and their components that are required to have a fire-protection rating need not conform to this Subsection.

Did you spot the key word “OR”?  This is significant as it offers compliance options. In Part 9 of the building code, it gives you two compliance paths. A Part 9 NAFS standard path and a Part 5 compliance path.  So let’s look at what Part 5 offers. Design and Construction (See Note A-

  1. Windows, doors, skylights, and their components shall be designed and constructed in accordance with
  2. A) Subsection 5.1.4., Section 5.3., Section 5.4. And Section 5.6., or
  3. B) The following standards
  4. i) AAMA/WDMA/CSA 101/I.S.2/A440, “NAFS – North American Fenestration Standard/Specification for Windows, Doors, and Skylights.”

Notice how it offers two compliance paths as well. The interesting part about this section of the code is that it provides the reader options.  To use a standard or to use an engineered method.  This was the intent all along as there are products that simply do not fit in the standard and many window manufactures have engineers on hand that can provide an engineered solution to many scenarios.  Let’s face it, we follow similar practices with other structural elements in a building.

So let’s consider how this applies to a project.

Consider how your specifications are written.  Do they say “windows to be in compliance with the BCBC, most current addition”.  If so, are you aware that you have given a window manufacturer the option to pick which path of compliance? Do you require all windows and doors in your specifications to be in compliance with the NAFS standard, but then require the window manufacturer to produce engineered shop drawings and Letters of Assurance?  Not that this is wrong, but you are doubling up on a compliance factor.

Now, what about Part 9 buildings that follow a Part 5 compliance path such as townhomes? According to the BCBC this is acceptable, though once the choice is made, it is important to ensure that the enforcement path is followed as well.

A Part 9 compliance path would require labels and a building inspector to complete an inspection. A Part 5 compliance path uses engineered shop drawings that require an engineer to complete inspections and provide Letters of Assurance. Be aware that the Part 9 compliance path uses more prescriptive tables that can be limiting, while the Part 5 engineered compliance path can use more precise evaluations which can result in a more cost-effective solution. 

Lastly, do you notice which word is missing from this text? It’s “Tested”. 

The original code language required all windows and doors to be “Tested” in accordance with NAFS, which was determined to be too difficult as not all products can be tested.  This word was changed to designed and constructed.  So to deal with this aspect, knowledge of how the NAFS standard works is integral. That’s for another time…

For more information, contact our Window Expert Anton Van Dyk. You can visit Anton's LinkedIn page or send him an email at Check out Anton's previous segments with CTV Vancouver where we further discuss the window industry and how homeowners and builders can achieve optimal performance and cost savings!

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Centra Windows is not only the manufacturer but also the installer of its product, which enables us to offer a full warranty, eliminating any confusion between product performance and installation. We view the house as a system and understand how each of the elements must work correctly to maximize the comfort and energy efficiency of your home. Contact our local Employee Owners at 1-888-534-3333 or send us an email at for more information about this topic and many more. You can also sign up for our biweekly newsletter for all the tips and tricks about the window industry.

Written by: Les Ferris , August 30, 2021
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