A proposed amendment to British Columbia’s building code would mandate cooling capability to maintain indoor temperature at no greater than 26⁰ Celsius in all new residential construction. If adopted, the new measure would be more stringent than the requirements of the 2020 model national building code.

The proposed change is part of a newly released package of code updates now open for public comment until June 16. Other amendments relate to accessibility, mass timber construction, earth quake design and radon safety, with the majority intended to align with the 2020 national code.

An accompanying code change document advises that B.C. is seeking to exceed national code standards largely in response to the 2021 heat wave, which brought temperatures in excess of 40⁰ C and was determined to be the cause of 619 deaths in a six-day period. More than two-thirds of the deceased were 70 or older, while sufferers of certain chronic diseases were particularly vulnerable. However, a subsequent report to B.C.’s chief coroner concluded that prolonged exposure to temperatures above 26⁰ C was a contributing factor in almost all cases.

The proposed new requirement calls for cooling capability to keep the temperature below that threshold within at least one living space in every dwelling unit. This could be accomplished with cooling appliances alone or in combination with other good engineering practices. Despite the code’s concurrent energy performance standards, the proposed new measure is meant as a contingency for extreme circumstances.

“Passive cooling measures should be explored at the design stage and, where necessary, mechanical cooling systems installed to provide a safe and healthy living space,” the proposed code change states. “Some living spaces in a dwelling unit may be more challenging than others to control indoor temperature, so it is the designer’s choice which living space (minimum of one) is capable of maintaining the design temperature.”