The transport of carbon monoxide from a burning compartment located on the side of a hallway

Abstract

An experimental study was conducted to investigate the transport of high concentrations of carbon monoxide (CO) from a burning compartment located on the side of a hallway. Opening sizes of 0.04 and 0.12 m2 were used to vary the ability of the jet of fire products entering the hallway to entrain surrounding gases. By controlling the depth of the upper layer of oxygen-deficient combustion gases accumulated in the hallway during preflashover, the oxygen concentration of the gases entrained into the jet of fire products entering the hallway was varied. An increase in the upper-layer depth resulted in higher CO and UHC yields and lower CO2 yields. When the depth of the layer fell below the bottom of the opening, downstream CO yields were found to increase to levels equivalent to or greater than yields measured inside the compartment, with the highest yields measured in experiments with external burning. Using the external burning as a flow visualization tool, the gases were observed to be transported nonuniformly down the hallway when the burning compartment was on the side. The bulk flow of the gases was to cross the hallway and then flow down the side of the hallway opposite the compartment. This nonuniformity in gas transport within the hallway was also evident in spatial and temporal measurements of species concentrations and temperature. In the hallway, during the postflashowever period of the compartment fire, concentrations of CO greater than 2.0% were measured at locations along the wall opposite the compartment, while CO concentrations of only 0.8% were measured on the compartment side of the hallway. The data presented provides the first explanation for the tragic results of fires in health care facilities where CO inhalation was responsible for numerous deaths, and points to the necessary directions for reliable predictive tools.