J.A. Vı́lchez

Analytical expressions for the calculation of damage percentage using the probit methodology

Abstract In the modelling of accidents, difficulties arise when introducing data from figures and tables into a computer code. In order to solve this problem in relation to the estimation of the consequences of an accident on the population, analytical expressions for converting Probit variables into probability percentages and vice-versa, are presented. The results obtained have been compared with the results found in tables and figures from references. Very good agreement between the commonly used values and those obtained from the analytical expressions has been found.

Design of a computer tool for the evaluation of the consequences of accidental natural gas releases in distribution pipes

A computer system was designed to model releases of a gas to the atmosphere. This paper describes the mathematical models used to describe the phenomenon: source term (which can be applied to gases with an ideal behaviour), turbulent jet, jet fire (including thermal radiation vulnerability models) and atmospheric dispersion (both for light and neutral gases), as well as the software and hardware used in the system.

Study of the severity of industrial accidents with hazardous substances by historical analysis

Abstract This paper studies the levels of risk in industrial facilities where hazardous substances are used, evaluating the influence of certain variables on the severity of the accidents that have occurred until now. It makes use of the incidents recorded in the July 2001 version of the MHIDAS database. This study reveals that accidents in developed countries are less severe than those that occur in other geographical areas. Also, it establishes the influence on the severity (number of fatalities) of this kind of incident of certain factors: the type of incident and the type and amount of substance involved. Lastly, the extent to which current facilities comply to the risk tolerance criteria in various countries is evaluated with regards to incidents involving explosions.

A new approach to the estimation of the probable number of fatalities in accidental explosions

This paper presents a new methodology for estimating the probable number of fatalities in accidental explosions in fixed installations, as a function of the amount of the flammable substance involved. A review of the procedure proposed by Marshall (1977) (Marshall, V.C., 1977 How lethal are explosions and toxic escapes? The Chemical Engineer, August 1977, 573-577). reveals its limitations, given the great dispersion of ungrouped data. The proposed alternative enables the estimation of the maximum probable number of fatalities and the percentage of cases in which a certain number of fatalities is reached, based on the knowledge of the amount of material presumably involved and through the application of the historical analysis of accidents. It must be pointed out that the proposed method considers not only fatalities derived directly from the overpressure wave but also those due to thermal radiation or missile impact.

Effects of fire on a container storage system—a case study

The transportation of chemicals is often carried out using containers; a system characterised by the high density of the storage. In such cases, if there is a fire in one container it will affect the adjacent ones. The effects of such an accident are studied through the analysis of a case: a fire on two containers located on a ship. The possibility of BLEVE occurrence is analysed, as is the thermal radiation and the dispersion of smoke.

Hazard index for runaway reactions

Abstract A hazard index has been developed which indicates the tendency of a system to undergo a runaway reaction. It is based on an energy factor-related to the heat of reaction-which is affected by a series of hazard and safety factors. These factors have been obtained from statistical studies, and have been adjusted so that the runaway index varies from 1 to 100.

Calculating concentration contour co-ordinates using integral plume models

Abstract A mathematical model is proposed which allows the prediction of the contour, for a given concentration, of a plume caused by a release into the atmosphere of substances either heavier or lighter than air. The application of the model to different cases has given results close to those obtained from other models. Its introduction into the computer code of any dispersion model provides a tool useful in risk analysis and environmental assessment.

Updating the economic cost of large-scale industrial accidents: Application to the historical analysis of accidents

Abstract This paper analyses the feasibility of applying different update rates of industrial prices to the economic assessments of accidents with special emphasis on those related to the chemical process industry. The advantages and disadvantages of applying this technique to the historical analysis of accidents are analysed and compared with the results obtained with the five most widely used indexes. The results of a general analysis of the historical evolution of the cost of accidents recorded in two prestigious databases are also presented. Valid data are obtained for decision-making with regard to insurance premiums, revaluation of assets and risk management (administration, safety management of large chemical complexes).

A New Concept When Designing Parking Areas for Lorries Carrying Dangerous Goods: The Dynamic Segregation

Publisher Summary Hazardous materials are often just transported through a city area; however, a significant number of lorries are actually obliged to remain in urban areas for a certain time (often overnight, sometimes for a weekend) awaiting embarking or, simply, to allow the drivers to comply with the legal regulations on the driving time. In the design of a parking area for vehicles carrying dangerous goods, several aspects have to be taken into account, not only those associated with the intrinsic danger of these materials but also the variety, the variability over time, and the mobility of lorries. There is an urgent need in industrial cities to find solutions to the difficult and sometimes dangerous situations caused by the transport of hazardous goods by road. These aspects have a noticeable influence on the location of the parking area, which must be at a safe distance from the populated areas and other industrial equipment. In addition, the scarcity and high price of land, especially in large cities, demands optimum design so as to accommodate, through criteria of flexibility, the maximum number of lorries in a fixed area while still maintaining the desired safety conditions.