Analysis of tenability, ventilation, and water application in large-scale residential fires

Fire;Residential;Tenability;Ventilation;Water Application;Large-Scale

Traina, Nicholas ; Kyritsis ; Dimitrios C.

关键词: Fire;    Residential;    Tenability;    Ventilation;    Water Application;    Large-Scale;   

Others  :  https://www.ideals.illinois.edu/bitstream/handle/2142/42358/Nicholas_Traina.pdf?sequence=1&isAllowed=y

美国|英语

来源: The Illinois Digital Environment for Access to Learning and Scholarship

【 摘 要 】

This study presents the analysis of large-scale residential fire experiments that were performed at Underwriters Laboratories in Northbrook, Illinois. These experiments were focused on the tenability conditions within residential fire environments and the effect of ventilation and water application on the fire environment. Experiments were conducted in one-story and two-story residential structures, with nine occurring in the one-story structure, and eight occurring in the two-story structure. Tenability conditions were determined based on CO inhalation and temperature data. In the one-story structure, CO untenability was reached, on average, 6 min. after ignition for experiments with ignition in the living room or bedrooms. In the two-story structure, CO untenability was reached, on average, 12 min. after ignition for experiments with ignition in the family room or bedrooms. In the one-story structure, CO untenability was reached prior to ventilation, which means that trapped occupants would likely be deceased in an actual fire. Times to CO untenability were drastically improved in rooms with doors shut to the fire environment, showing the importance of shutting oneself off from the fire if trapped inside a burning structure. Times to thermal untenability were typically longer than times to CO untenability, suggesting CO poisoning is more of a danger to occupants than burns. Water application was shown to improve the fire environment significantly for even small water applications. The range of duration for water applications in these experiments was 6-17 s. The correlation between duration of water application and temperature reduction inside the fire environment was not statistically significant, which suggested that the effect of water application in reducing the temperatures in the fire environment was largely due to the initial suppression of the fire in the first few seconds of water application. Temperatureiiireduction in non-fire rooms, i.e. rooms without materials on fire, demonstrated a fairly linear relationship with the temperature before water application. It was found that this relationship was different between straight streams and fog streams. Fog streams initially have larger temperature reductions than straight stream applications, but as time reaches approximately 30 s after water application, the temperature reductions become larger for the straight stream and remain larger thereafter. Additionally, "pushing the fire" i.e. the effect of water application increasing the temperature in the rooms adjacent to the fire room, was observed only in fog streams. The reason for this "pushing the fire" effect was due to the entrainment of gases in the fog stream, which created an inflow of gases into the fire room, thus raising the pressure of the fire room and sending the hot gases into the adjacent rooms. This effect was not witnessed in straight stream applications, which was expected since entrainment of gases in the straight stream water application was negligible. A study of ventilation techniques showed that shutting the front door behind firefighter entry and venting far from the seat of the fire reduced the potential for flashover and the danger to firefighters.