The collapse of 1WTC, New York City, 10:28am Sept 11, 2001.
Photo by 9/11 Photos CC BY.
Note: It is open access so you can read and share it without need for a subscription. We have posted in open access also our Matlab code to calculate the fire temperatures in zenodo.
Accidental fire can be disastrous, especially in buildings. The effect of fire on structural stability is critical in regard to safe evacuation and safe access for fire fighters, financial losses, and lost business. This is particularly the case in tall buildings where extended evacuation times are required due to phased evacuation practices. The World Trade Centre Tower fires in 2001 have highlighted the need of a more realistic design tools to represent fires in large compartments.
Innovative architectural designs of modern buildings already provide a challenge to structural engineers. This is above all the case in structural fire engineering. However, most of the understanding and current design codes are based on the assumption of uniform fires in a compartment. In previous work, we have shown that fires in large, open-plan compartments, typical of modern architecture, travel from one part of it to another with non-uniform temperature distribution. These fires are referred to as travelling fires. And Travelling Fires Methodology (TFM) has been developed to account for the travelling nature of fires.
|Illustration of a travelling fire and distribution of gas temperatures.|
The focus of this latest paper is on the improvement of the calculations of traveling fire (iTFM) to account for better fire dynamics, and the analysis of the effect on structural members. The proposed changes represent a simple yet powerful fire model. In particular, our paper shows that:
- Using data from experiments and real fires, we limit the range of possible fire sizes thus reducing the time required for conduct TFM studies.
- Analytical expressions are presented for generating time–temperature curves which are independent of grid size (previous versions of TFM) and can be easily calculated with any mathematical tool.
- Introduction of flapping term leads to reduced near-field temperatures for smaller fire sizes which cover a range between 800 and 1200 °C, as observed in real building fires.
- The location of the peak temperature in the compartment is found to occur at the end of the fire path (i.e. far half of the compartment from the ignition source).