Evaluating and improving the fire performance of radiative cooling balsa wood

The focus of this study is to investigate the fire performance of cellulose-based radiative cooling wood. Although offering passive cooling benefits, radiative cooling wood’s inherent flammability is a critical drawback. This research evaluated pristine balsa wood (PW), cooling wood (CW), and cooling wood flame-retarded with borax (FR CW). Fire performance was evaluated via cone calorimetry (20–50 kW m⁻²), thermal analysis (thermogravimetry and differential scanning calorimetry), and Fire Dynamics Simulator (FDS) modelling. The results demonstrate significantly enhanced fire safety for FR CW wherein the Critical Heat Flux increased by up to 80 % and ignition temperature by up to 36 % compared to CW. Borax treatment extended ignition times, promoted charring, and substantially reduced Heat Release Rate. The Fire Growth Index for FR CW at 50 kW m⁻² decreased by ≈ 77–81 %. FDS simulations confirmed significantly lower compartment fire temperatures with FR CW. This research shows that borax, an eco-friendly mineral, effectively mitigates fire risks in radiative cooling wood, improving key safety parameters like Heat Release Rate, Maximum Rate of Heat Emission, carbon monoxide, and smoke production, thus enhancing its viability as a sustainable construction material. • Borax treatment boosts Critical Heat Flux (80 %) and ignition temperature (36 %). • Borax promotes charring, substantially reducing Heat Release Rate. • Fire Growth Index for treated cooling wood decreased by ≈ 77–81 %. • FDS confirms lower compartment fire temperatures with borax-treated wood.