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Sensitivity Examination of the airEXODUS Aircraft Evacuation Simulation Model.


pdf icon Sensitivity Examination of the airEXODUS Aircraft Evacuation Simulation Model. (1457 K)
Bukowski, R. W.; Peacock, R. D.; Jones, W. W.

International Aircraft Fire and Cabin Safety Research Conference. Proceedings. November 16-20, 1998, Atlantic City, NJ, 1-14 pp, 1998.

Keywords:

aircraft certification; behavior models; evacuating (transportation); evacuation time; passenger vehicles; toxic hazards

Abstract:

The Building and Fire Research Laboratory at the National Institute of Standards and Technology (NIST) has been a leader in the development, application and evaluation of models for the simulation of fires and the associated hazards and risk to people. NIST's expertise is useful in the broader application of fire hazard analysis to transportation systems in general. Such a project related to passenger trains has been ongoing for several years, sponsored by the Federal Railroad Administration through the Volpe National Transportation Systems Center. For aircraft, a fire hazard analysis could determine not only the time required for evacuation, but also the time available, based on the fire performance of the total system. Such an application requires both predictive models of the fire environment and of passenger evacuation during fires. The Federal Aviation Administration (FAA) is interested in the use of computer simulation models for examining the compliance of commercial aircraft with FAA regulations for the evacuation of passengers and crew. This interest derives from both a desire to reduce the expense of testing every aircraft configuration and to reduce dependence on evacuation tests involving people and the attendant risk of injury in such tests. The FAA's plan is to allow the use of modeling to qualify derivative aircraft, those that exhibit variations in interior configuration or stretch versions, for which demonstration tests were performed on the basic version. There is also interest in using models to assess evacuation for advanced designs that may vary in significant ways from current passenger aircraft. An appropriately validated model could be used both to test compliance of derivative designs and to evaluate evacuation as part of the design of new aircraft prior to actual compliance testing. In the longer term, the coupling of an evacuation model with a fire model would allow designers to evaluate evacuation under more realistic fire conditions. One candidate model specifically developed to simulate the evacuation of commercial aircraft is airEXODUS developed at the University of Greenwich in the United Kingdom. The developers have been conducting extensive verification of the predictive accuracy of the model using data from the historical records of certification tests as a step in developing the capability of the model to simulate evacuation during a fire. The FAA asked the National Institute of Standards and Technology to examine the sensitivity of the airEXODUS model to reasonable variation in user inputs to determine if the model results might be unduly impacted without being obvious to those reviewing the results. A copy of the latest pre-release version (v 1.Ol) of the model was supplied to NIST by the developers for this purpose. NIST has studied the evacuation times for a simple geometry (a passenger rail coach car with exits at both ends) and found the times predicted by airEXODUS and two other emergency evacuation models were nearly identical. The following describes the results of an examination of airEXODUS as applied to two aircraft designs along with pertinent observations. However, any decision of the suitability of the model for regulatory purposes can only be judged by the FAA.