Does expanded polystyrene (EPS) present a serious fire hazard?
The EPS in an Fox Blocks has a flame retardant that allows the forms to be flame resistant. The EPS will melt when exposed to sustained temperatures over 300°F (149°C). The ignition point of the melted styrene is 600°F (315°C) (wood is approximately 500°F (260°C). Fox Blocks have been tested to meet the building code requirements for flame spread and smoke development, plus Fox Blocks may be used as fire resistant rated wall assemblies in schools and hospitals.
What is EPS made from?
Polystyrene is virgin material, manufactured from petroleum. Polystyrene beads are expanded with steam heat to be up to 40 times their original volume and then the expanded beads are molded again by steam heat into 25⁄8″ rigid insulation panels to create a Fox Blocks ICF.