The analysis of domino accidents triggered by vapor cloud explosions

doi:10.1016/j.ress.2004.11.012

Reliability Engineering & System Safety

Volume 90, Issues 2–3, November–December 2005, Pages 271-284

https://doi.org/10.1016/j.ress.2004.11.012 Get rights and content

Abstract

Domino effect is a well-known cause of severe accidents in the chemical and process industry. Several studies pointed out that the more critical step in the quantitative assessment of domino hazards is the availability of reliable models to estimate the possibility and probability of the escalation of primary accidents. This work focused on the revision of available models for the quantitative estimation of damage probability to plant equipment caused by pressure waves generated by a primary accident. Available data on damages to process equipment caused by pressure waves were analyzed. Several specific probit functions for different elements of process equipment were obtained from the analysis of failure data. The analysis of blast wave propagation in different types of explosions allowed the estimation of the expected damage probability as a function of distance from the explosion center and of explosion strength. The results obtained were used to assess safety distance criteria and to evaluate the contribution to individual risk of domino effect due to pressure waves.

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

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The analysis of domino accidents triggered by vapor cloud explosions

Abstract

Introduction

Section snippets

Damage probability of process equipment

Assessment of peak overpressure as a function of scaled distance

Definition of a case-study

Conclusions

Loss prevention in the process industries

Guidelines for chemical process quantitative risk analysis

The estimation of domino incident frequencies—an approach

Process Safety Environ Prot

Evaluating the probability of major hazardous incidents as a result of escalation events

J Loss Prev Process Ind

Domino effect evaluation of major industrial installations: a computer aided methodological approach

Models for domino effect analysis in chemical process industries

Process Safety Prog

Explosion hazards and evaluation

Guidelines for evaluating the characteristics of VCEs, Flash Fires and BLEVEs

The effect of nuclear weapons

Limit states of process equipment components loaded by a blast wave

J Loss Prev Process Ind

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