Paper Title
BUILDING THERMAL PERFORMANCE AND HEAT STRESS: INFORMING ADAPTIVE ARCHITECTURE FOR CLIMATE RESILIENCE

Abstract
Introduction Rising global temperatures and frequent heat extremes challenge indoor workplaces to maintain thermal comfort without increasing energy use. This study establishes baseline impacts of conventional building materials to inform smart material development—a transformative approach to climate resilience offering dynamic responses to environmental conditions, reducing heat loads by 20–40%, and improving occupant comfort. Materials and Methods: We examined the relationship between building envelope materials, heat strain indicators (HSIs), productivity loss (PL), and heat-related illness (HRI) symptoms through a cross-sectional study of 1,600 indoor workers during summer months (2022-2024) from 21 workplaces in Tamil Nadu with varying building envelope characteristics. Wet Bulb Globe Temperature (WBGT) monitors measured heat exposures; HSIs were quantified using standard methods, and validated questionnaires assessed HRIs and PL. Results Roof materials and building envelope significantly impacted workplace heat exposure, with concrete panels (U-value ≤ 1.8) in 41% of workplaces resulting in an average indoor WBGT of 30.4 ± 3.0°C and exposing 83% of workers to unsafe levels. Better-insulated buildings (U-value > 1.8) demonstrated substantially lower heat-related health impacts and improved thermal comfort. HRIs were significantly reduced (20% vs. 89%), along with HSIs including core body temperature rise >1°C (13% vs. 9%), sweat rate >1 L/hr (11% vs. 7%), and urine specific gravity >1.020 (32% vs. 26%). Long-term kidney function impairment was also reduced (eGFR ≤ 89: 19% vs. 34%). Additionally, productivity loss was substantially lower in better-insulated facilities (1% vs. 9%) and resulted in better business outcomes. Conclusions Our findings demonstrate a direct correlation between building envelope thermal performance and worker health outcomes and productivity in heat-exposed environments. These results establish the need for improved building materials to reduce thermal loads and mitigate heat-related illnesses. Smart materials offer a promising pathway to climate-resilient buildings, benefiting both worker health and business productivity. Keywords - Building Materials; Thermal Comfort; Passive Cooling; Heat-Related Illness; Productivity Loss; Climate Resilience