Bench-scale studies of poly(vinyl chloride) fires with water mist

Bench-scale tests to study the effect of water mist on burning solid poly(vinyl chloride) (PVC) were carried out with a cone calorimeter. Water mist was discharged from a small nozzle under two operating pressures, 0.4 and 0.7 MPa. The corresponding water flow rates were 103.5 and 134 mL/min, respectively. The cone angle of the discharged water spray was 90°, and the volume mean diameter of the mist was about 90 μm. The results were useful in understanding the effects of discharging water mist to suppress the diffusion flame from burning PVC. The reignition process also was studied. The testing method was appropriate for studying the interaction between water mist with smaller droplets and the diffusion flame in a confined space. There, the combined effects of oxygen displacement, gas phase, and fuel surface cooling were the key extinguishing mechanisms. The critical water mist application rate on burning PVC under different thermal radiative heat fluxes was able to be determined.