How to interpret the word “OR” in the BC Building Code
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. We 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
- Except as provided by Sentence (2), windows, doors, skylights and their components shall be designed and constructed in accordance with
A)Article 22.214.171.124., or
2. 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.
126.96.36.199. Design and Construction (See Note A-188.8.131.52.)
- Windows, doors, skylights, and their components shall be designed and constructed in accordance with
A) Subsection 5.1.4., Section 5.3., Section 5.4. And Section 5.6., or
B) The following standards
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, however 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…
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