A series of vertical fire suppression experiments on rigid polyurethane (RPU) and flexible polyurethane (FPU) with/without water spray were conducted in a standard chamber. A new video processing method was developed to determine the pyrolysis front position of wind-aided flame. Averaged flame height, carbon monoxide/hydrogen cyanide concentration, view factors, and extinguishing time were determined with operating pressure varying from 0.15 MPa to 0.4 MPa. The experimental study showed that water spray would suppress RPU/FPU fire mainly by fuel surface cooling. Furthermore, the perfect water spray pressure for RPU/FPU fire suppression was 0.3 MPa and the corresponding water application rate was 0.7511 mg/(cm2·s).
Experimental study of transitional behavior of fully developed under-ventilated compartment fire and associated facade flame height evolution