Active protection against fire: Enhancing the flame retardancy of sandwich panels using an expandable graphite layer formation

An active protection sandwich panel utilizing expandable graphite (EG) was developed to address the release of hazardous gases during building fires involving sandwich panels, leveraging its excellent thermal performance. When exposed to heat, EG expands and forms a barrier, effectively preventing the spread of fire and blocking harmful gas emissions generated from the insulation material. Flame retardancy tests demonstrated that EG-applied sandwich panels exhibited significantly lower peak and total heat release, as well as reduced smoke generation. Quantitative analysis of gas emissions during combustion confirmed their lower toxicity levels. The cone calorimeter test revealed that the EG-applied sandwich panels showed a remarkable 67.1% reduction in peak heat release rate (HRR) and a 51% decrease in total heat release compared to panels without EG (PF). Furthermore, total smoke generation reduced by an impressive 94%. This study affirms the effectiveness of EG in improving flame retardancy and reducing harmful gas emissions in sandwich panels. In addition, there is significance in analyzed the effect of EG on improving fire resistance performance through the fractional effective dose analysis method, which assesses human respiratory tolerance to combustion byproducts.