Experimental studies to investigate merging behaviour in a staircase

Abstract

SUMMARY The quantification of merging flows and the factors that influence evacuee merging behaviour are important considerations in our understanding of emergency evacuation of particularly high‐rise buildings, and essential for better escape route design and evacuation modelling. This paper presents the results of three evacuation studies to investigate merging flows and behaviours on stairs. Stair:floor merging ratios are provided together with specific flows from the floor and stair. The potential influence of the geometrical location of the floor relative to the stair and the occupant population is discussed. The results indicate that, despite differences in the geometrical location of the door in relation to the stair and the relative stair/door width, the merging was approximately 50:50 across the duration of the merge period in each of the buildings studied. Differences in merge patterns were however evident throughout the merge periods in each of the buildings, particularly in the case where the floor occupants approached from a corridor adjacent to the incoming stair, in which case floor occupants took priority during periods of slower movement. There were also suggestions that some occupant characteristics such as gender or role may have a potential influence on merging, with very obvious deference behaviour of a few individuals dictating the merging in a mixed occupancy building. The studies highlight the potential influence of geometrical location of floor relative to the stair, relative door/stair widths and population characteristics on merge patterns and indicate that much more work is required in this area. Copyright © 2011 John Wiley & Sons, Ltd.

Fire evacuation in high-rise buildings: a review of human behaviour and modelling research

“…Gender or role may also influence evacuation performance from a behavioural perspective. For example, the experiments carried out by Boyce et al (2009) showed that deference behaviours may arise during the evacuation process in stairs (e.g. male groups giving priority to women or groups with children, staff guiding other occupants, etc.…”

“…Galea et al (2008c) suggested that in high-rise buildings, floors should be linked to the landing on the opposite side to the incoming stair in order to increase the efficiency of the flows. Boyce et al (2009) discussed the merging ratios, performing experiments that show that despite differences in the geometric location of the door in relation to the stair, the merging ratio was always approximately 50:50.…”

Transparency vs magic numbers: The development of stair design requirements in the Italian Fire Safety Code

“…Previous studies comparing stair code provisions and evacuation simulation results are in line with these findings. In fact, previous research includes a series of high occupant density study cases of multi-storey evacuations in different buildings that were carried out to measure key parameters including specific flow rates, merging ratios, occupant densities in stairs and the effects of their interactions on evacuation flows and timing [33]. When these cases were modelled using the evacuation model Gridflow, a good agreement was found [10].…”

“…The traditional capacitive method is modified considering the results of recent experimental research on merging flows ratio [33][34][35][36], where the measured average merging flow ratio at stair landings (considering a congested situation, a standard stair configuration and a homogenous population) is observed to be approximately 50:50, i.e., As demonstrated in [37], the time needed by all occupants to evacuate from the floor of the building that is emptied last is not dependent on the assumed merging flow ratio. Also, merge ratio is not an issue when the holding capacity of the stairs between floors is sufficient for the entire population of each floor.…”

The Process of Verification and Validation of Building Fire Evacuation Models

“…For example, the evacuation community is currently debating the appropriate stair merging ratio to be adopted in tall buildings. Few experimental studies [Boyce et al, 2012 To date, the definition of a complete set of experimental data to be used for the validation of the core behavioural components of evacuation models is not possible due to the limited amount of experiments suitable for validation. Nevertheless, this section suggests a set of examples of experimental/actual data-sets that are suitable for the validation of specific aspects of evacuation.…”