Availability of data on accidents and chemical inventories, together with assessment and analysis tools is a prerequisite for integrated control of industrial accidents. Although Turkey has a developing industry, legislative measures for control of industrial accidents are lacking, past accidents are not systematically enlisted and industrial facilities and hazardous substances thereof are not properly registered. While some accident data is available in international databases, they are incomplete and erroneous. In the present study, a decision support system has been developed for collection and analysis of past accident information, assessment of current accident potentials of industrial establishments and modeling of probable accidents to reveal risks possessed thereby. The system supports web based multilingual and multi-user environment,and aims contribution of all interested parties in a collaborative manner. Information on technological accidents can be systematically archived together with reference data and visual materials. Initial data covering a time period of 30 years has been provided. The system is capable of storing hazard classifications and physico-chemical properties of substances, and providing standardized data for calculations. It can determine major-accident potential of industrial facilities as dictated by the 96/82/EC Directive of the EU and update relevant information automatically as required. An easy to use accident model for rapid assessment of off-site consequences of industrial accidents is also featured. Developed system allows integrated management of data on industrial accidents and provides decision support tools for assessing current and future accident potential,which can be used for national as well as the EU needs.

A questão da segurança funcional das indústrias de processos vem recebendo uma atenção crescente pela comunidade científica mundial, uma vez que se observa a possibilidade de ocorrências de acidentes e as consequências indesejadas que estes acidentes têm provocado. Essas indústrias podem ser consideradas como parte de uma classe de sistemas denominados Sistemas Críticos, que são caracterizados pela possibilidade de ocorrência de falhas críticas, que resultam em acidentes com perdas de vidas humanas, danos ao meio ambiente e perdas financeiras envolvendo custos significativos de equipamentos e propriedades. Estes fatos justificam a necessidade de uma nova abordagem no que se refere ao design de processos, design de controle de processos, análise e controle de riscos e avaliação de riscos. Um dos desafios pertinentes à segurança funcional está associado a como vincular os cenários de acidentes aos requisitos para projetos de sistemas de controle relacionados à segurança das indústrias de processos de forma sistemática. Por sua vez, a possibilidade de ocorrência de eventos críticos e/ou eventos indesejados não observados ou ocultos, como fatores relevantes associados à evolução da sequência de eventos que culmina na ocorrência de um acidente. Neste contexto, o desafio está em aprimorar a eficácia destes sistemas de controle, que envolve o desenvolvimento de uma solução capaz de supervisionar o processo de evolução de falhas críticas, a fim de se garantir um nível de segurança funcional adequado e que esteja em conformidade com as normas internacionais aplicáveis IEC 61508 e IEC 61511. Portanto, estas considerações trazem novos requisitos para o projeto de sistemas de controle desta natureza, capaz de englobar modelos de acidentes e processos de evolução de falhas críticas. Uma solução é a consideração das abordagens de prevenção e mitigação de falhas críticas de forma integrada e interativa. Além disso é necessário abordar novas técnicas e conceitos para que se possa desenvolver um sistema de controle capaz de rastrear e atuar nos processos de evolução de falhas desta natureza. Uma possibilidade consiste em considerar o princípio de defesa em profundidade aliado à propriedade de diagnosticabilidade segura. O atendimento a este novo conjunto de requisitos não é trivial e se faz necessário integrar diferentes formalismos para o desenvolvimento de soluções adequadas. Portanto, este trabalho apresenta uma metodologia para o projeto de um sistema de controle baseado no conceito de segurança funcional para indústrias de processos, e que propõe: (i) uma arquitetura de controle para prevenção e mitigação de falhas críticas, (ii) extensão da classificação de barreiras de segurança focando na automação via sistemas instrumentados de segurança (SIS) (iii) framework para a síntese de sistemas de controle relacionados à segurança baseado em modelos de acidentes e que contempla os seguintes métodos: (a) elaboração do HAZOP, (b) construção de modelos de acidentes, (c) integração dos modelos de acidentes com o HAZOP e (d) geração dos algoritmos de defesa para a prevenção e mitigação de falhas críticas, a partir de técnicas de modelagem usando extensões da rede de Petri: Production Flow Schema (PFS) e Mark Flow Graph (MFG). A metodologia proposta foi verificada, a partir de exemplos de aplicação investigados na literatura. / The issue of the functional safety of process industries has been receiving increasing attention from the world scientific community, since it has stated the possibility of occurrences of the accidents and the related undesired consequences. These industries can be considered as part of a system class called critical systems, which are characterized by the occurrence of critical faults, which can result in accidents involving loss of life, damage to the environment, and financial losses involving equipment and property. These facts justify the need for a new approach that addresses: process design, process control design, risk analysis and control, and risk assessment. One of the challenges related to functional safety is associated with how to integrate accident scenarios to the requirements for the design of safety-related control systems of the process industries in a systematic way. Furthermore, there is the possibility of the occurrence of the unobserved or hidden undesired and / or critical events, as relevant factors associated to the evolution of the sequence of the events that corroborates in the occurrence of an accident. In this context, the challenge is to improve the effectiveness of these control systems, which involves the development of a solution capable of supervising the process of evolution of the critical and / or undesired events, in order to guarantee an adequate level of functional safety, and that complies with the applicable international standards IEC 61508 and IEC 61511. Therefore, these considerations bring new requirements for the design of control systems of this nature, capable of encompassing the accident models and the critical fault evolution processes. One solution is to consider critical fault prevention and mitigation approaches in an integrated and interactive way. In addition, it is necessary to addresses new techniques and concepts in order to develop a control system capable of tracking and acting in the evolution processes of faults of this nature. One possibility is to consider the principle of defense-in-depth coupled with the property of safe diagnosability. The fulfillment of this new set of requirements is not trivial and it is necessary to integrate different formalisms for the development of adequate solutions. Therefore, this work presents a methodology for the design of a safety-related control systems based on the concept of functional safety for the process industries, which proposes: (i) a control architecture for the prevention and mitigation of the critical faults, (ii) an extension of the classification of the safety barriers focusing on automation via safety instrumented system (SIS), (iii) a framework for the synthesis of the safety-related control systems based on accident models and which includes the following methods: (a) elaboration of the HAZOP study, (b) construction of the accident models, (c) integration of the accident models with the HAZOP study, and (d) generation of the defense algorithms for the prevention and mitigation of the critical faults, via modeling techniques using extensions of the Petri net: Production Flow Schema (PFS) and Mark Flow Graph (MFG). The proposed methodology was verified, from application examples investigated in the literature.

A questão da segurança funcional das indústrias de processos vem recebendo uma atenção crescente pela comunidade científica mundial, uma vez que se observa a possibilidade de ocorrências de acidentes e as consequências indesejadas que estes acidentes têm provocado. Essas indústrias podem ser consideradas como parte de uma classe de sistemas denominados Sistemas Críticos, que são caracterizados pela possibilidade de ocorrência de falhas críticas, que resultam em acidentes com perdas de vidas humanas, danos ao meio ambiente e perdas financeiras envolvendo custos significativos de equipamentos e propriedades. Estes fatos justificam a necessidade de uma nova abordagem no que se refere ao design de processos, design de controle de processos, análise e controle de riscos e avaliação de riscos. Um dos desafios pertinentes à segurança funcional está associado a como vincular os cenários de acidentes aos requisitos para projetos de sistemas de controle relacionados à segurança das indústrias de processos de forma sistemática. Por sua vez, a possibilidade de ocorrência de eventos críticos e/ou eventos indesejados não observados ou ocultos, como fatores relevantes associados à evolução da sequência de eventos que culmina na ocorrência de um acidente. Neste contexto, o desafio está em aprimorar a eficácia destes sistemas de controle, que envolve o desenvolvimento de uma solução capaz de supervisionar o processo de evolução de falhas críticas, a fim de se garantir um nível de segurança funcional adequado e que esteja em conformidade com as normas internacionais aplicáveis IEC 61508 e IEC 61511. Portanto, estas considerações trazem novos requisitos para o projeto de sistemas de controle desta natureza, capaz de englobar modelos de acidentes e processos de evolução de falhas críticas. Uma solução é a consideração das abordagens de prevenção e mitigação de falhas críticas de forma integrada e interativa. Além disso é necessário abordar novas técnicas e conceitos para que se possa desenvolver um sistema de controle capaz de rastrear e atuar nos processos de evolução de falhas desta natureza. Uma possibilidade consiste em considerar o princípio de defesa em profundidade aliado à propriedade de diagnosticabilidade segura. O atendimento a este novo conjunto de requisitos não é trivial e se faz necessário integrar diferentes formalismos para o desenvolvimento de soluções adequadas. Portanto, este trabalho apresenta uma metodologia para o projeto de um sistema de controle baseado no conceito de segurança funcional para indústrias de processos, e que propõe: (i) uma arquitetura de controle para prevenção e mitigação de falhas críticas, (ii) extensão da classificação de barreiras de segurança focando na automação via sistemas instrumentados de segurança (SIS) (iii) framework para a síntese de sistemas de controle relacionados à segurança baseado em modelos de acidentes e que contempla os seguintes métodos: (a) elaboração do HAZOP, (b) construção de modelos de acidentes, (c) integração dos modelos de acidentes com o HAZOP e (d) geração dos algoritmos de defesa para a prevenção e mitigação de falhas críticas, a partir de técnicas de modelagem usando extensões da rede de Petri: Production Flow Schema (PFS) e Mark Flow Graph (MFG). A metodologia proposta foi verificada, a partir de exemplos de aplicação investigados na literatura. / The issue of the functional safety of process industries has been receiving increasing attention from the world scientific community, since it has stated the possibility of occurrences of the accidents and the related undesired consequences. These industries can be considered as part of a system class called critical systems, which are characterized by the occurrence of critical faults, which can result in accidents involving loss of life, damage to the environment, and financial losses involving equipment and property. These facts justify the need for a new approach that addresses: process design, process control design, risk analysis and control, and risk assessment. One of the challenges related to functional safety is associated with how to integrate accident scenarios to the requirements for the design of safety-related control systems of the process industries in a systematic way. Furthermore, there is the possibility of the occurrence of the unobserved or hidden undesired and / or critical events, as relevant factors associated to the evolution of the sequence of the events that corroborates in the occurrence of an accident. In this context, the challenge is to improve the effectiveness of these control systems, which involves the development of a solution capable of supervising the process of evolution of the critical and / or undesired events, in order to guarantee an adequate level of functional safety, and that complies with the applicable international standards IEC 61508 and IEC 61511. Therefore, these considerations bring new requirements for the design of control systems of this nature, capable of encompassing the accident models and the critical fault evolution processes. One solution is to consider critical fault prevention and mitigation approaches in an integrated and interactive way. In addition, it is necessary to addresses new techniques and concepts in order to develop a control system capable of tracking and acting in the evolution processes of faults of this nature. One possibility is to consider the principle of defense-in-depth coupled with the property of safe diagnosability. The fulfillment of this new set of requirements is not trivial and it is necessary to integrate different formalisms for the development of adequate solutions. Therefore, this work presents a methodology for the design of a safety-related control systems based on the concept of functional safety for the process industries, which proposes: (i) a control architecture for the prevention and mitigation of the critical faults, (ii) an extension of the classification of the safety barriers focusing on automation via safety instrumented system (SIS), (iii) a framework for the synthesis of the safety-related control systems based on accident models and which includes the following methods: (a) elaboration of the HAZOP study, (b) construction of the accident models, (c) integration of the accident models with the HAZOP study, and (d) generation of the defense algorithms for the prevention and mitigation of the critical faults, via modeling techniques using extensions of the Petri net: Production Flow Schema (PFS) and Mark Flow Graph (MFG). The proposed methodology was verified, from application examples investigated in the literature.

<p>Although traditional hazard analysis techniques, such as failure modes and effect analysis (FMEA), and fault tree analysis (FTA) have been used for a long time, they are not well-suited to handling modern systems with complex software, human-machine interactions, and decision-making procedures. This is mainly because traditional hazard analysis techniques rely on a direct cause-effect chain and have no unified guidance to lead the hazard analysis. The Systems Theoretic Accident Model and Process (STAMP) is based on systems theory to try to find out as much as possible about the factors involved in a hazard, and with providing clear guidance as to the control structure leading to the hazard.</p> <p>The Darlington Nuclear Power Generating Station was the first nuclear plant in the world in which the safety shutdown systems are computer controlled. Although FTA and FMEA have already been applied to these shutdown systems, Ontario power generation felt that it is still useful to try recent advances to evaluate whether they can improve on the previous hazard analysis.</p> <p>This thesis introduces the two most common traditional techniques of hazard analysis, FTA and FMEA, as well as two systemic techniques, STPA (which is a hazard analysis method associated with STAMP), and the Functional Resonance Accident Model (FRAM). The thesis also explains why we chose STPA to apply to the Darlington Shutdown System case, and provides an example of the application as well as an evaluation of its use compared with FMEA and FTA.</p> / Master of Applied Science (MASc)

The dissertation deals with the analysis of roundabout design elements and their impact on accidents. The analysis objective was to identify the important elements of roundabouts that have impact on accidents. In order to achieve this goal, the multifactorial statistical safety assessment method was used on the basis of a representative sample of data, by developing several safety performance functions, verifying them and interpreting the result. Several design elements, which from the point of view of the traffic accident mechanism belong to the infrastructure factor, have been identified: AADT, average diameter, entrance width, entry angle, direct passage angle, location and many others. The original sample contained about 1200 roundabouts, which were reduced to 200 based on data availability. Accident frequencies were monitored between 2009 and 2016, i.e. for eight years, resulting in total 2674 roundabouts accidents. The result is an accident prediction model, developer based on roundabout approach design elements, and map of critical roundabouts, identified based on empirical Bayes estimate of accident frequency. Following approach parameters were identified: AADT, entry angle, distance between collision points, deviation of angles between approaches, presence of apron, presence of bypass, entry type, presence of pedestrian crossing and surrounding area type.