Smoke Species Generation In Prototypical Building Structure

Data spanning decades have indicated that fatalities in fires were mainly caused by fire smoke especially the carbon monoxide. This study are based on the typical building structure apparatus, consisted of fire compartment and the hallway, and this thesis concludes two main parts of study: one is the effect of fire location on smoke species generation in compartment fires; and the other part focused on smoke species generation feature in an enclosed compartment fire.In the first part of study, two different sized oil pans were located at three different locations in compartment, and species concentration, temperature and mass quality were collected synchronously and data in the steady-state periods were analyzed. In this study, the whole compartment was taken as a control volume and parameters as neutral plane height, integrated average concentration of carbon monoxide and CO yields were used to show the smoke hazard. The relationships as smoke flow rate versus neutral plane height or heat release rate or neutral plane height versus CO integrated average concentration or yields were studied. Data of CO integrated average mole fraction and CO yields indicated that the smoke hazard of corner-located fires, no matter the fire located at the near corner or the remote corner, was distinctly higher than the center-located fires. Integrated average concentration and yield data of carbon monoxide were calculated and correlated well with the Global Equivalence Ratio (GER), however, they failed to show a single curve and three separated curves were found corresponding to three different fire locations, which indicated that fires at the corner especially at the front corner produced distinctly higher level of carbon monoxide and CO concentration as high as 0.6% was detected even in the well-ventilated condition. Comparisons between the previous data and the present data demonstrated that the CO yield data from this study was extremely higher than previous data, and a discussion about the current engineering practice suggested that they may over-evaluate or under-evaluate the level of CO generation in fires.when fire start from an enclosed space (viz. ventilation is confined), air in the space will be consumed quickly and smoke containing fatal level of species as CO will be accumulated in a very short period. In the second part of study, two series of experiments were conducted in a compartment attached with a long hallway, in order to study features of species generation in an enclosed compartment and its influences on adjacent space. Results indicated that CO concentration level increased three times in 40 seconds intervals and fatal level of CO flowed into the adjacent hallway after the door was suddenly opened. As burning going on in an enclosed fire, more CO but less CO₂ was generated out of the same amount of fuel consumed. In addition, the burning area effects on species generation were studied and data demonstrated that a critical value of burning area existed which could makes the fire most dangerous.