Quantitative assessment of flame-retardant treated wallpaper ignition behaviour under compartment fire conditions

This study examines whether the Korean Fire Safety Act’s 45° burner test adequately represents wallpaper behaviour under compartment fire heating. Specimens were a matched pair of flame-retardant (FPR) and ordinary (PR) PVC wallpapers from one manufacturer, and a paper wallpaper (T) with no flame-retardant counterpart; findings are evidence from these specimens, not a general ranking. Thermogravimetric analysis in air and nitrogen showed the treatment raised the peak decomposition temperature by 9 °C and activation energy by 20 ~ 30 kJ/mol. However, FPR and PR volatile releases converged near 300 °C, above which the gas-phase effect is exhausted. Assuming FPR’s ignition temperature is that of PR plus 9 °C, the predicted ignition delay over 10–50 kW/m2 is only 11 ~ 14 %. The persistent effect is char oxidation resistance—leaving a 500 °C air residue of 35.6 % for FPR versus 26.7 % for PR—which limits smouldering and re-ignition rather than preventing ignition. Flame retardancy thus resists localised ignition sources, but treated and untreated products remain indistinguishable under developed fire radiation. Three indicators are proposed using TGA, basic material properties, and a thermally thin ignition model: critical heat flux, an effective flame-retardant temperature limit near 300 °C, and char residue in air.