Quantitative risk analysis for the Amerigo Vespucci (Florence, Italy) airport including domino effects

Feasibility studies for airport facilities require quantitative assessment of the effects of the routine operations on the area surrounding the planned installation. In some countries such analyses are mandatory and the targets for which the effects need to be evaluated often include: cultural heritage, natural habitat, as well as human comfort and health. Regarding the latter issue, of main concern is the fatality risk due to airport traffic, primarily considering accidents due to landing and take-off operations. Accidents leading to crash may include fuel fires and explosions, but also trigger domino effects such as industrial accidents, possibly amplifying adverse consequences. Quantitative risk analysis for airport facilities is the topic of the study presented, where a probabilistic framework to evaluate the annual fatality risk for airports and surrounding areas is discussed. The risk metric is the individual risk (IR), and the methodology contemplates the tools and procedures to compute the annual expected number of accidents that result in fatality for each point in the area surrounding the airport. Three causes contribute to the evaluation of IR: (i) direct aircraft impact, (ii) heat radiation produced by the burning of fuel possibly released in the crash; (iii) heat radiation or intoxication because the crash involves industrial facilities storing or treating relevant amounts of hazardous materials. The risk analysis requires competencies mainly from three fields: (a) stochastic modelling for uncertainty management and probabilistic evaluation; (b) aeronautical engineering for the modeling of aircraft operations and dynamics that may result in an accident and, finally, (c) chemical engineering for the combustion modeling and for the analysis of cascading effects on industrial targets (also called domino in the following), as well as for the evaluation of health consequences. The developed method is thoroughly discussed in the paper and applied to the foreseen upgrade of the Florence (Italy) airport Amerigo Vespucci, which shows its potential effectiveness in decision making preparatory to airports’ design.