Assessment of fire behaviour of polyisocyanurate (PIR) insulation foam enhanced with lamellar inorganic smart fillers

Modern day energy codes are driving the design and multi-layered configuration of exterior wall systems with significant emphasis on achieving high performance insulation towards improving energy performance of building envelopes. Use of highly insulating polyisocyanurate (PIR) based insulation materials enhanced with eco-friendly lamellar inorganic fillers contributes to meeting energy performance requirements, environmental challenges and cost reduction without undue compromise of the overall building fire safety. Towards that end, the aim of the current work is to assess the fire behaviour of PIR foams enhanced with lamellar inorganic smart fillers, namely Layered Double Hydroxides (LDHs) and ZrP. Experimental results indicate that fire reaction properties and thermal stability of foam samples enhanced with three types of lamellar inorganic smart fillers are evaluated using cone calorimeter (CC) and thermogravimetric (TGA) analysis. The initial degradation temperature of PIR-layered filler samples increases compared with neat PIR foam, indicating that incorporation of flame retardants decelerates the degradation of PIR foam and as result increases the thermal stability of PIR foam. Thermal decomposition of the PIR samples occurs in two distinct stages associated with the degradation of the urethane-urea linkages of the hard segment, releasing low calorific capacity products and the degradation of polyol derived products with higher calorific capacity than those derived from isocyanate. Increasing the filler content results in increased char formation and decreased peak Heat Release rates (HRR).