Search

A differential computer model specifically designed to quantify smoke movement during a fire in a high-rise structure is described. The basic conservation equations are transformed into a computer code which can be used to determine the paths that smoke will take during a fire. The program is a tool for fire protection engineers to design a smoke management plan with the ultimate goal of improving occupant safety in the event of a fire. The computer code is based on a modified and improved differential smoke control model for the conditions in the floor spaces, stairwells and elevator shafts and it considers a complete set of variables that influence the motion of smoke throughout the building. Program output suggests ways to alter the pressure distribution within the building by using air handling equipment, so that occupants will have smoke-free areas on the floors and inside of the fire escape stairwells. Results for several example cases are provided, and the results are used to illustrate how smoke movement can be managed in order to mitigate dangerous conditions within the building.

A study on building occupant characteristics in mass rapid transit (MRT) stations in Singapore is reported in this paper. The characteristics studied include age group and gender distributions, commuters’ response to fire emergency alarms and their awareness of locations of exits, their walking speeds on walkways and stairs. The study took advantage of the fare card system used in Singapore to ascertain the age group spectrum of the commuters. Surveys were conducted among the MRT commuters to establish their intended response to three types of fire alarm systems, namely the fire alarm bell, the live announcement and the pre-recorded message. Commuter walking speeds were measured with the aid of video recording and on-site observation. The distributions of age groups in the MRT commuters were found to be statistically significantly different from that of general public, as there were mainly adults and fewer children and elderly in comparison to the general population. The distributions of gender groups in the MRT commuters were also found to be statistically significantly different from that of general public, as the female/male ratio among the commuters was greater than that in the general population. The survey results indicated that commuters intended more likely to respond to live announcement warning system than to the other two systems. The commuters’ awareness of egress routes was poor. It was also noted that there was no statistically significant difference in the responses by the two gender groups to the three fire alarm warning systems but the study indicated the statistically significant gender difference in the awareness of fire escape routes. A significantly large proportion of commuters was found unaware of or unfamiliar with the current fire escape route provisions in the MRT stations from the survey. The unimpeded walking speed was found to be gender and age dependant and it may not be appropriate to apply one walking speed for all commuters. Weak correlations were found for linear fit of walking speeds over a wide range of pedestrian density on walkways and staircases. Keywords: Commuters; Evacuation