Consider the Code
When analyzing curtainwall and fenestration systems’ energy performance criteria, first check on the applicable codes. The most recent, national model building and energy codes may not be the most current ones, or modified versions may be enforced by the authority having jurisdiction over the project in question.
Provinces, territories, municipalities and some self-legislating authorities, such as First Nations, retain responsibility for how code editions and modifications are adopted and enforced except for federal buildings, where the most recent model code is automatically applicable. The National Research Council Canada (NRC) provides a high-level list of code adoption and enforcement throughout the country. Additional verification at a municipal and project-specific level also is strongly recommended.
In all known Canadian codes and their provincial adaptations, each refers to “U-factor” or “U-value.” This is the industry-accepted measurement indicating the rate of thermal energy transmission in a fenestration system.
- Government of Canada, National Research Council Canada (NRC), “Model code adoption across Canada,” https://nrc.canada.ca/en/certifications-evaluations-standards/codes-canada/model-code-adoption-across-canada
U-factor measurements consider the combined role of the glass, opaque panels and framing members, and take into account three different ways a curtainwall or fenestration system transfers energy: convection, conduction and radiation.