A CONSEQUENCE MODEL FOR CHLORINE AND AMMONIA BASED ON A FATALITY INDEX APPROACH

In this paper, a simple and transparent consequence model for chlorine and ammonia is proposed based on a fatality index. The parameters for the model can be estimated from historical accident data and avoid the large number of assumptions necessary in traditional models. This approach was attempted for two values of the exponent of the mass (0.75 and 1.0), from which a simple linear model (with exponent 1.0) is proposed. This estimates consequences for three different population density classes: rural, semi-urban (or industrial) and urban. The distribution of the number of fatalities relative to the estimated average number of fatalities was found to approach an S-shaped distribution function. A simple distribution function gives, however, results comparable to the more complex form. For the particular case of assessing the risk of transportation of chlorine by rail in U.S.A. the fatality index model seems to be less conservative, and closer to empirical observations than the traditional models.