Importance of Exit Stairwells

FYI - I sent this to my office the other day and wanted to pass it along. It is a pretty interesting study.

From the Journal of Fire Protection Engineering, this is usually a very technical look at fire growth and related papers but there was a very good study that came out and was published recently that we can all learn from.

APPROXIMATING EVACUATION using COMPUTER SIMULATION
The scenario used the World Trade Center I as the model

The model predicts that the total evacuation time of the building for the 8239 survivors, population, to be 1 hour and 27 minutes ~2 minutes. This time compares favorably with the observation that the building collapsed after 1 hour 42 minutes. The model results also suggested that while the insertion of the firefighters into the building did impact the evacuation efficiency of individuals, it had minimal detrimental impact on the overall evacuation efficiency. Had the building been fully occupied, 25,000 people, it was predicted to take appropriately 2 hours, 18 minutes to evacuate all survivors.

The results suggested also that had at least one staircase survived from top to bottom, it is possible that everyone that survived the initial trauma of the impact could have managed to safely escape. This shows the importance of staircase dispersal within buildings.