Carbon monoxide production during underventilated fires in corridors

This work presents experimental results and non-dimensional correlations of factors and conditions affecting carbon monoxide (CO) production in corridor-like enclosure fires. Thirty eight experiments were performed in a three metre long corridor-like enclosure having a cross section 0.5 m x 0.5 m, door-like openings in the front panel and a propane gas burner located near the closed end being flushed with the floor. Measurements of carbon monoxide concentrations were performed at locations inside the enclosure and also in the exhaust duct of a hood collecting the combustion products for direct comparison. Visual observations through the opening revealed that flames were detaching from the burner for tests with global equivalence ratios (GERs) greater than one for the burning inside the enclosure (underventilated fires). After detachment, flames were travelling towards the opening then finally stayed anchored in the vicinity of the opening and emerged outside. After flames were visible outside, the concentration of CO inside the corridor increases to much higher levels owing to the recirculation of gases inside the enclosure behind the flames. A correlation between CO concentration inside the enclosure and GER was found with CO increasing initially but then decreasing for high global equivalence ratios. An additional correlation was found between the CO yield and the GER in the enclosure before the flames reached and then, anchored at the opening of the enclosure. Finally, it was found that the ratio of CO to smoke yield, yco/ys, is not constant but increases for global equivalence ratios of the enclosure greater than one in contrast to its value being constant for over ventilated conditions.