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A domino effect triggered by a natural event (a so-called Natech domino effect) represents a typical high-impact low-probability (HILP) event, which may lead to catastrophic consequences. The presence of safety barriers could have an impact on the effects by impeding propagation patterns and mitigating potential consequences. However, coordinating and maintaining safety measures to establish an effective barrier system against Natech domino effects is complicated. In this paper, the concept of what constitutes a safety barrier and the principles of barrier management are reviewed. Subsequently, the complex phenomenon of Natech domino effects is studied at the individual installation level, while the propagation pattern is explored at the system level. The application of safety barriers is discussed with the aim of coping with potential Natech domino effects. A systematic framework of barrier management is developed to establish and improve the barrier system in the whole cycle (design & construction, operation, accident, recovery & improvement) of a chemical industrial area. The challenges are discussed to highlight future study needs.

Gas explosion accidents easily cause severe casualties in Chinese underground coal mines. Systematic analysis of accident causation is crucial for the prevention of gas explosions. This study identifies the representative risk factors of gas explosions and determines the interrelationship among these risk factors to highlight weak links and develop countermeasures. A total of 21 representative risk factors of gas explosions were identified through 128 case studies and front-line investigations. On this basis, a five-level hierarchical structure model of gas explosions was established to explore the complex interrelationships among the representative risk factors based on a combination of the Decision-Making Trial and Evaluation Laboratory (DEMATEL) and Interpretive Structural Modeling (ISM) methods. Moreover, the Matrix of Cross Impact Multiplications Applied to Classification (MICMAC) method was applied to achieve risk factor classification into four clusters, namely, driving factors, linkage factors, dependent factors and autonomous factors. The results indicated that the interrelationships and emergence properties among the risk factors may cause gas explosions, which should give more attention to the interrelationships among multiple factors and multiple subsystems for coal enterprises. Meanwhile, the complex geological conditions, poor safety supervision, inadequate safety education and training, incomplete execution safety regulations and poor safety technology and input are the long-term focus of risk management for coal enterprises. Finally, 10 countermeasures were proposed to control these representative risk factors and interrelationships. The results are helpful to the development of gas explosion risk management policies and to the preferential allocation of limited resources to resolve these issues.

Historical data analysis shows that escalation accidents, so-called domino effects, have an important role in disastrous accidents in the chemical and process industries. In this study, an agent-based modeling and simulation approach is proposed to study the propagation of domino effects in the chemical and process industries. Different from the analytical or Monte Carlo simulation approaches, which normally study the domino effect at probabilistic network levels, the agent-based modeling technique explains the domino effects from a bottom-up perspective. In this approach, the installations involved in a domino effect are modeled as agents whereas the interactions among the installations (e.g., by means of heat radiation) are modeled via the basic rules of the agents. Application of the developed model to several case studies demonstrates the ability of the model not only in modeling higher-level domino effects and synergistic effects but also in accounting for temporal dependencies. The model can readily be applied to large-scale complicated cases.

Safety (veiligheid) en security (beveiliging) zijn belangrijke concepten bij respectievelijk de bescherming en beveiliging van kritieke infrastructuren. Het veilig maken en beveiligen van kritieke infrastructuren is optimaal wanneer safety en security zoveel mogelijk samen worden bekeken en daar waar mogelijk worden gentegreerd. Aan de hand van een praktijkonderzoek wordt nagegaan in welke omstandigheden en onder welke voorwaarden safety en security in de praktijk als gentegreerd kunnen worden beschouwd en waarom dat al dan niet zo is. Vervolgens wordt via interviews bepaald wie welke verantwoordelijkheid heeft bij de bescherming en de beveiliging van kritieke infrastructuur in Belgi en wat hierbij de visie is van de verschillende stakeholders en actoren. Gebruik makend van bestaande proactieve beschermingsprogrammas, wordt een theoretisch raamwerk ontwikkeld dat drie spanningsvelden, safety en security, publieke en private sector en proactieve en reactieve acties, op een holistische manier benadert, zodat de bescherming en beveiliging van de kritieke infrastructuur optimaal (vanuit een multidisciplinair kader) kan worden aangepakt.

This article addresses drivers and partner features in vertical or horizontal cooperation. A survey is used to assess their impact and to evaluate whether respondents give significantly different scores to comparable influencing factors depending on the type of cooperation. The results show that internal stakeholder support and investments needed for collaboration turn out to be more critical in the case of horizontal collaboration. Innovation potential of the partner features and the fit between the cooperating organizations are judged as more important partner features in the case of horizontal cooperation.

Adding new equipment (e.g. an installation) to an existing network of chemical installations alters the existing danger equilibrium of the chemical surrounding complex. Therefore, precaution measures for preventing external domino effects have to be updated. The Hazwim framework, based on the Process Hazards Analysis (PHA) techniques of Hazop, What-if analysis and the Risk Matrix has been developed to prevent knock-on effects for an existing cluster of chemical plants. However, preventive safety measures for new installations based on PHA implementation in the design phase are preferred to the use of protection- and mitigation measures derived from non-design PHAs. The risk analysis techniques suggested by the authors allowing for the design of inherently safe installations are then evaluated based on Belgian government recommendations and Belgian Seveso plant practices. Next, based on the proposed techniques this paper presents a framework called ‘Installation Plus’ for redesigning external domino accident prevention when adding an installation to an existing chemical facility. Installation Plus integrates enhanced cross-company cooperation on process hazards and risk assessment activities with the selection of Safety Instrumented Functions offering the appropriate integrity requirements.

This paper makes an original contribution towards managing knock-on major accidents or accidents caused by so-called domino effects by presenting a 5 step evaluation model. First, a ‘domino danger unit’ for every couple installations in a complex network consisting of chemical installations is calculated. Second, an enumerative approach for the relative ranking of domino effects sequences between types of installations and for different accident scenarios and dangerous substances is worked out. Third, a ‘Segment Risk Factor’ is calculated by considering the frequency of the domino path segment and the overall danger of the path segment towards domino accidents. Finally, an overall classification of domino path sequences is made in order of decreasing danger. Such a classification of domino effects sequences can be implemented by safety management as a tool to support decisions on prevention prioritization.

Securing critical infrastructures is a complex task. Required information is usually scarce or inexistent, and experts’ judgments may be inaccurate and biased. In this paper, two methodologies dealing with data scarcity, imprecision, and uncertainty are presented: Evidential network and Credal network. Evidential network is a graphical technique based on Dempster-Shafer Theory to explicitly model the propagation of epistemic uncertainty among variables while Credal network is an extension of Bayesian network to deal with sets of probabilities, known as Credal sets, based on experts’ judgments. Both methodologies constitute robust frameworks to account for high degree of imprecision on data, producing informative results despite the low-informative input. In the present study, the power in expressing uncertainty of these two methodologies have been showed, and their differences have been described through their application to a case study of security vulnerability assessment. Results demonstrate the substantial equivalence of the two methodologies in prognostic analysis, thus, an approximate updating procedure of Evidential network through equivalent Credal network has been proposed, to overcome the lack of possibility to compute updating in the context of Dempster-Shafer Theory.

In this article, an extensive literature review has been carried out about process safety education. We drafted a process safety model able to systematize the literature review and investigated scientific papers as well as professional articles and so-called grey literature. The presence of a common background emerged, although possibilities for optimization of university curricula are possible, as well as harmonization within universities in different countries and between universities and industry. More collaboration in the field of process safety education is recommended, thereby also involving government agencies and/or control authorities and inspection bodies. In the light of the prevention of major accidents in the chemical industry, the process safety education topic deserves to receive more attention from all parties involved, that is, academia, industry and authorities.

Chemical facilities may be targets of deliberate acts of interference triggering major accidents (fires, explosion, toxic dispersions) in process and storage units. Standard methodologies for vulnerability assessment are based on qualitative or semi-quantitative tools, currently not tailored for this type of facilities and not accounting for the role of physical protection systems. In the present study, a quantitative approach to the probabilistic assessment of vulnerability to external attacks is presented, based on the application of a dedicated Bayesian Network (BN). BN allowed the representation of interactions among attack impact vectors and resistance of process units, which determine the final outcomes of an attack. A specific assessment of protection systems, based on experts’ elicitation of performance data, allowed providing a knowledge support to the evaluation of probabilities. The application to an industrial case study allowed the assessment of the potentialities of the approach, which may support both the evaluation of the vulnerability of a given facility, and the performance assessment of the security physical protection system in place.

This paper analyzes 21 years of data related to unintentional hazardous materials (hazmat) releases on air, marine, and rail transportation modes reported in the United States (U.S.) -- although their origins and destinations may be outside the U.S. The authors' analysis reveals thousands of cases have occurred and their impacts vary by mode. These impacts include material losses, carrier damages, property damages, response costs, and remediation and clean-up costs. There appears to be some reduction in the frequency of incidents and accidents as regulations have been promulgated, although the authors cannot attribute causation. They review suggests that enhanced regulations and attentiveness have probably led to better reporting of hazmat occurrences. Moreover, developing and maintaining safer processes and designing safer products, containers, and systems can play an important role in minimizing hazmat releases.

Process accidents in the early 1980s have drawn process safety into the main stream. In the 1990s, risk-based approaches were developed to bring safety into design as well as economic considerations. In the 2000s, the inherent safety approach began to be practiced on a limited basis, and process safety evolution made significant progress. As process systems continue to become more complex and operations move into remote and harsh environments, traditional risk analysis may no longer be sufficient. Dynamic risk assessment is the basis for the next generation of risk and management approaches that help to enable safer complex process systems operating in extreme environments. This article investigates the main contributions in the area of dynamic risk assessment. Then, an overall framework for dynamic risk management of process facilities is proposed.