Experimental and numerical investigation of fire hazard of vertical greenery systems

This study investigates the fire hazard of vertical greenery systems (VGS) with experiments performed at the bench-scale and medium-scale followed by numerical simulations. Bench-scale tests were conducted in cone-calorimeter while the medium-scale experiments consisted of a test rig with dimensions 100 cm × 30 cm × 3 cm (height × width × depth). 28 cone-calorimeter tests were conducted under four cone heat flux levels, which represented four woodwool moisture content (MC) levels (between 8 % and 20 %) and four bulk densities (BD) of the fuel bed (between 50 kg/m3 to 100 kg/m3). Cone test results revealed that flammability was increased with the reduction of MC and BD under four flammability parameters, namely, the ignitability, combustibility, flame duration (FD) and consumability. The medium-scale experiments conducted with three different MCs and three different BDs showed that the UFS rate increases with the decrease of MC and BD. Average UFS rate was over 3.48 cm/s while the maximum temperatures along the fuel bed reached values over 700 °C in all scenarios. The medium-scale experiment scenarios were numerically simulated in the fire dynamic simulator (FDS) and the predicted upward fire spread rate showed good agreement with only slight deviations. However, the temperature recordings at different heights were overpredicted. •Bench-scale tests were conducted in cone-calorimeter.•Medium-scale test rig dimensions were 100 × 30 × 3 cm (height × width × depth).•Fire hazard was increased with the decrease of moisture content and bulk density.•Medium-scale experiment scenarios were numerically simulated in FDS.•Predicted upward fire spread rate showed good agreement with slight deviations.