Reaction-to-fire performance of vertical laminated toughened glass panels with different inter-layer materials when exposed to an external heat flux

Abstract

This paper investigates the fire performance of laminated glass used in balcony balustrades under external heat flux conditions. Experiments examined ignition times and heat release rates (HRR) from laminated glass with different thicknesses of toughened glass with four inter-layer types: polyvinyl butyral (PVB), SentryGlas Plus (SGP), ethylene-vinyl acetate (EVA), and cast-in-place (CIP). Parameters included glass thickness, sample size, thermal exposure, and the condition of the glass pane (broken or unbroken). Thinner PVB samples showed a poorer reaction-to-fire performance when compared to the three other laminate types. At 75 kW/m² exposure conditions the 17.5 mm thick PVB samples ignited after 5.6 ± 0.9 min versus 8.3 ± 1.6 min for 25.5 mm think samples, faster times than equivalent samples containing SGP and EVA. When 21.5 mm thick unbroken samples were exposed to 75 kW/m², the peak HRR was ∼167 kW/m² for PVB and SGP samples compared to ∼85 kW/m² for EVA and CIP. However, the HRR from a 17.5 mm thick PVB sample peaked at 256 kW/m² versus 122 kW/m² for an equivalent SGP sample. Findings supported using 17.5 mm thick toughened laminated glass with a PVB inter-layer for a series of large-scale balcony fire spread tests in a related study.