Heat Stress Indicators in Certification Schemes for the Built Environment

Overheating issues in buildings have gained increased attention due to the growing frequency and severity of extreme weather events across the world due to climate change. Thus, there is a need for buildings to become resilient, being able to protect occupants from heat stress caused by heatwaves and power outages that could follow. Nowadays a variety of heat stress indicators are used to evaluate heat strain on people. This critical review study presents the comparison of different international building certification schemes with regards to their indoor heat stress indicators and assessment criteria. Six certifications are included, namely WELL, LEED, BREEAM, DGNB, RELi and HQM. The comparison concerns the relation between the indoor thermal comfort indices and the heat stress indices, and the implementation of different indicators including feasible scenarios and limits. These heat stress indicators were implemented to compare in the existing measurement data. In conclusion, LEED and RELi demonstrated the most comprehensive considerations of indoor heat stress evaluations among these certifications. An analysis on the acquired indicators on the extracted indoor environmental data of a naturally ventilated building showed that the potential of heat stress risks increased when PMV was over 1.