Multi-scale experimental and numerical study demonstrates that fungal decay accelerates timber ignition and fire spread, highlighting elevated fire hazards in wooden buildings.
Key Points
To evaluate how accelerated fungal decay alters the combustion behavior of timber from microscopic material pyrolysis to building-scale fire spread.
Tested Douglas-fir samples subjected to accelerated fungal decay using cone calorimetry, thermogravimetry-derivative thermogravimetry (TG-DTG), and impedance-based non-destructive testing.
Constructed a material-level pyrolysis model and conducted full-scale numerical fire simulations using Fire Dynamics Simulator (FDS).
Fungal decay preferentially broke down cellulose and hemicellulose; after 90 days, the maximum pyrolysis temperature fell by 16.9 °C, ignition temperature dropped by 15.14 °C (TG-DTG) and 14.65 °C (cone calorimetry), and toxic CO emissions rose significantly.
Building simulations showed accelerated fire development, earlier flashover, and an increase in peak heat release rate from 11.6 MW to 16.2 MW.
A dual-scale Comprehensive Fire Risk Index (CFRI) indicated that fungal decay amplified overall fire risk by up to 148.8%.