Synergistic heat-absorber/insulator laminate for lightweight fire shields

Building fires impose stringent demands on protective panels, requiring high fire-resistance limits (FRL), low weight and thickness, and modular construction compatibility. Conventional mono-functional boards, such as pure gypsum or insulation panels, fail to meet these combined targets. Here, we propose a bilayer Heat-Absorber/Insulator Laminate (HAIL), integrating a gypsum board (GB, heat absorber layer) and a ceramic fiber board (CFB, insulating layer), and systematically elucidate its full-cycle synergistic fire-protection mechanism. A research framework—incorporating ISO 834 furnace tests, finite-element simulation, and transient heat-conduction theory—is employed to optimize thickness ratio and material parameters. Results indicate that the highest FRL of HAIL was observed when the CFB fraction was between 40% and 60%. A pronounced synergistic effect emerges when the thermal conductivity of the insulating layer is less than half that of the heat-absorbing layer. The enhanced fire performance stems from three synergistic effects: significantly prolonged temperature plateau, effectively delayed onset of phase change, and markedly reduced temperature rise rate after phase change. Compared with a conventional pure gypsum-board configuration, the HAIL with CFB fraction reduces total thickness by 9–15% and areal density by 40–44% at the same FRL while increasing by approximately 37–50% at an equal thickness. A 40 mm HAIL panel achieves an FRL greater than 120 min, meeting the critical 2-h structural fire-resistance requirement. The quantitative design criteria and thickness–areal-density maps established in this study provide a practical basis and design framework for the engineering application of HAIL in lightweight building envelopes and non-load-bearing structures.