The Committee met for two days to go over task group updates and listen to climate data research. The Task Group on Extreme Wind provided an update proposing the introduction of tornado loads as a new, distinct design load, separate from regular wind. For Part 9 buildings, a tornado hazard zoning approach was recommended, dividing Canada into high, low‑to‑moderate, and no‑tornado (EF0) hazard regions. 

NRC provided a presentation reviewing the rationale of several new temperature design indices to better reflect future climate conditions and system design life. These include a January 5% temperature based on a projected 20‑year return period for heating systems, and new July 1% and 5% temperatures using the same return period. Heating degree days referenced to a 10 °C base temperature (HDD10), cooling degree days referenced to a 10 °C base temperature (CDD10), CDD18, and CDD26 would potentially be progressively introduced for highly insulated buildings. Furthermore, it was discussed that CDD alone may not fully capture overheating risk where humidity plays a significant role, however, based on the presented analysis, CDD was identified as a better indicator for overheating thresholds than July dry‑bulb temperature. 

The importance of harmonizing climatic data between the NBC and provincial/territorial codes was discussed as well. A proposal was presented by NRC to revise reference locations, increasing the total from 689 to 784, to improve accuracy and consistency across jurisdictions. Some design temperatures have already been updated based on revised observation locations, while the reference period for the 2030 NBC update remains under development. 

Lastly, an issue was identified with Part 9 snow loads, where some 2025 values are more than 44% higher than 2020 value. Members of the committee are working on rewording certain Code calculations to reduce the difference between the load values which will then be included in the 2025 NBC errata. 

For more information, contact bilal.el-zaylaa@chba.ca