The analysis of domino accidents triggered by vapor cloud explosions
Introduction
The hazards caused by domino effect are well-known in the literature [1], [2] and are widely recognized also in the legislation. The assessment of these hazards was already required by the first ‘Seveso’ European Community Directive (82/501/EEC), on the control of major accidents caused by dangerous substances. The ‘Seveso-II’ Directive (96/82/EC) extended these requirements also to the assessment of possible domino effects outside the site under consideration (e.g. to nearby plants).
Although the severe consequences of domino accidents are known, a well established and widely accepted methodology for the identification and the quantitative assessment of accidents caused by domino effects is still missing. Indeed, several qualitative criteria were proposed in the literature to identify the possibility of domino events, mainly based on equipment vulnerability tables (e.g. see [1] and references cited therein), whereas only few pioneering studies addressed the problem of the quantitative assessment of risk due to domino effects [3], [4], [5], [6]. Nevertheless, these studies were not specifically focused on the development of models for the evaluation of primary accident escalation.
In several accidents where a ‘domino effect’ took place, the main responsible for the escalation was the propagation of pressure waves generated by the primary accident (an explosion). The present study focuses on the assessment and further development of probabilistic models to evaluate the damage to process equipment loaded by overpressure, in the framework of domino effect evaluation in quantitative risk analysis. Probit models were used to relate the peak overpressure to the expected damage probability. These were coupled to simplified models for peak overpressure as a function of distance from the explosion centre and of explosion strength, thus allowing a straightforward estimation of damage probability and of safety distances for escalation effects.
Section snippets
Damage probability of process equipment
A necessary starting point in the assessment of probabilistic models for accident propagation due to overpressure is the analysis of both theoretical and experimental data on damage to equipment loaded by blast waves. Details on explosion types and behaviour are reported elsewhere [1], [7], [8]. It is only worth mentioning that pressure (or blast) waves are characterised by static and dynamic overpressures, and by the total duration (impulse) of the wave. The interaction of the pressure waves
Assessment of peak overpressure as a function of scaled distance
The assessment of safety distances and damage probabilities needs to be coupled to the specific explosion type and parameters (e.g. total explosion energy), not only to the equipment characteristics. To this aim, some generalizations on the primary scenario may be useful. Indeed, with specific reference to assessment of domino effects, only explosive phenomena which can propagate damages at a significant distance from the source point of the explosion are of concern. This point of view gives
Definition of a case-study
The models previously defined were specifically addressed to be used within the QRA framework to assess the contribution to industrial risk of domino effect caused by blast waves. Thus, it is important to verify if the approach developed above may be used in the quantitative assessment of risk due to domino events. A case study was defined, derived from the actual lay-out of an existing oil refinery. Table 8 shows a list of equipment considered in the analysis. Fig. 6 shows a scheme of the
Conclusions
In the framework of the quantitative assessment of domino effect, probit models were derived for the estimation of damage probability to process equipment due to blast waves. Different probit models were introduced, in order to take into account the different structural characteristics of different categories of process equipment. The probit models were coupled to simplified models for peak overpressure calculation. This allowed a straightforward approach to the estimation of safety distances
References (38)
Loss prevention in the process industries
(1996)Guidelines for chemical process quantitative risk analysis
(2000)- et al.
The estimation of domino incident frequencies—an approach
Process Safety Environ Prot
(1991) - et al.
Evaluating the probability of major hazardous incidents as a result of escalation events
J Loss Prev Process Ind
(1999) - et al.
Domino effect evaluation of major industrial installations: a computer aided methodological approach
(1996) - et al.
Models for domino effect analysis in chemical process industries
Process Safety Prog
(1998) - et al.
Explosion hazards and evaluation
(1983) Guidelines for evaluating the characteristics of VCEs, Flash Fires and BLEVEs
(1994)- et al.
The effect of nuclear weapons
(1977) Limit states of process equipment components loaded by a blast wave
J Loss Prev Process Ind
(1997)
Structural response to accidental explosions and fires on offshore process installations
J Loss Prev Process Ind
Canvey: an investigation of potential hazards from operations in the Canvey Island/Thurrock Area, London
Risk analysis of a typical chemical industry using ORA procedure
J Loss Prev Process Ind
Vulnerability model: a simulation system for assessing damage resulting from marine spills
Probit analysis
The hazard of pressure tanks involved in fires
Ind Eng Chem Res
Unconfined deflagrative explosion without turbulence: experiments and model
J Hazard Mater
The blast wave generated by spherical flames
Combust Flame
Methods for vapour cloud explosion blast modelling
J Hazard Mater
Cited by (72)
Emergency response in cascading scenarios triggered by natural events
2024, Reliability Engineering and System SafetyDynamic risk assessment method for urban hydrogen refueling stations: A novel dynamic Bayesian network incorporating multiple equipment states and accident cascade effects
2024, International Journal of Hydrogen EnergyVulnerability assessment of storage tanks exposed to simultaneous fire and explosion hazards
2023, Reliability Engineering and System SafetyAnalysis of structural response of storage tanks subject to synergistic blast and fire loads
2022, Journal of Loss Prevention in the Process IndustriesVulnerability assessment method for domino effects analysis in chemical clusters
2022, Process Safety and Environmental Protection