Engineers’ responsibilities: which version of the National Building Code should be used?

What is the NBC?

Published by the National Research Council of Canada, the NBC is a “model”[1] code, which means that it’s developed and updated by an independent organization of provinces and municipalities that use it. It’s revised about every five years and has no legal status[2] until it is adopted by the provinces and municipalities that will use it. However, there’s a rather significant period between when the new version of the NBC is published by the National Research Council of Canada and when it’s legally adopted.

The province of Québec publishes the Construction Code (QCC). The most recent version of this code has been in force since June 15, 2015 (QCC 2015); it includes the NBC 2010 and certain Québec-specific requirements that were added. The QCC 2015 is still in force, despite that it’s now 2019 and the NBC 2015 was published in June 2015[3]. It’s the same in other Canadian provinces that don’t systematically adopt the most recent version of the NBC. For example, in Ontario, the current version contains references to the NBC 2010[4]. On the other hand, British Columbia adopted the NBC 2015 in December 2018.

The National Research Council of Canada continuously studies seismic loads and snow or wind loads, so it’s possible for local seismic or climatic loads to change significantly as a result of more exhaustive studies and a deeper knowledge of locations. Engineers must then decide which design criteria to adopt for the project.

Engineers have few resources to guide them in their decisions. An initial reference could be professional associations whose mission it is to protect the public. However, because of their status, these organizations rely on legal standards. As for engineers, they’re required to keep their knowledge up-to-date, which means they have to know the scope of information contained in the most recent version of the NBC. And beyond public safety, engineers must also consider the financial consequences related to the version of the code they choose to rely on.

The court held that engineers have a primary professional duty to ensure public safety in all projects where they place their seal. Engineers also have the duty to remain current on developments in the field of engineering in which they practice.

Echoes of jurisprudence

As the following case illustrates, jurisprudence can guide decision-making. The Clouâtre vs. Factory Mutual Insurance Company[5] case, which involved the failure of a roof structure due to excessive snow loads, established a precedent.

Let’s go over the case briefly. Following a design mandate in the summer of 1999, the construction of a large warehouse was completed in June 2000. The NBC that was officially in effect at the time was NBC 90. Commentary 34 in the Supplement to the NBC 90 includes a warning for large-size buildings, but also indicates that there is no sufficient data to make accurate recommendations (ref. 5, para. 37). At the time the work was carried out, the NBC 95 was already available and included a calculation method for large-scale rooves, similar to that of the named warehouse (ref. 5, para. 39).

The judge concluded that the engineer should have considered the most up-to-date information available regarding snow loads, even if the calculation method was indicated in the NBC 95, which was then available, but not yet legally adopted.

Engineer obligations

Engineers have the duty to keep their knowledge up-to-date and to properly understand the consequences related to the code they are relying on. When the most recent version includes stricter requirements than the previous version, engineers must notify their client and explain the full picture. If the client refuses to use the most recent version for financial reasons, engineers must inform their client in writing of the consequences their decision could have.

These consequences can be twofold. If the damages are material, the potential litigation will be civil. However, if the failure causes harm to individuals, the cause could be criminal. In either case, engineers must demonstrate that they exercised their due diligence in outlining their own and client responsibilities.

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[1] https://en.wikipedia.org/wiki/...

[2] https://en.wikipedia.org/wiki/...

[3] https://www.oaq.com/actualite/...

[4] https://nrc.canada.ca/en/certi...

[5] https://unik.caij.qc.ca/recher...[Jurisprudence,Doctrine,L%C3%A9gislation]&m=detailed&bp=results, paragraphe 41