Composite sandwich panels are increasingly used in transport (aviation, railways, shipping) and other high specification applications (e.g. bridges, offshore, wind turbines) because they offer low weight, mechanical and structural properties, fatigue and corrosion resistance.
Fire performance must be ensured, including maintaining resistance to compression forces during fire. In this study, performance of panels using PVC core (low price benchmark), polyisocyanurate (PI) foam with glass fibre (stitching together the two panel skins) and balsa wood was tested at bench scale, with and without PIN flame retardant in the foam, applied to covering fabrics and on the panel surface. Intumescence from PIN FRs crucially increased the time to structural failure. Both PI foam and balsa offered significantly better time to failure than PVC foam. Balsa was better without flame retardant, but the best of all performance was using PI foam with PIN FR in the foam (better than balsa, where FRs could only be applied on the surface materials).
“Fire stability of glass-fibre sandwich panels: The influence of core materials and flame retardants”, A. Hörold et al., Composite Structures 160 (2017) 1310–1318 http://dx.doi.org/10.1016/j.compstruct.2016.11.027