Safety lifecycle management in the process industries : the development of a qualitative safety related information analysis technique

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Operational Data Framework for Safety Instrumented Systems : A Case Study in Functional Safety and Reliability

In various industries, companies are adopting functional safety measures to address safety concerns, adhere to standards, and manage complex systems. This research is focused on ensuring the reliable operation of Safety Instrumented Systems (SISs) by emphasizing the reliability data. The study examines methodologies for collecting data, classifying failures, mitigating risks, and complying with international safety standards. Through a case study in the energy and marine power industry, a theoretical framework is developed to utilize operational data for assessing SIS performance in the form of a new Engine Safety System (ESS). By complying with IEC standards 61508 and 61511 and incorporating the framework into the ESS's Functional Safety Management Plan, the research addresses key challenges such as data collection, failure analysis, and performance verification. The primary research questions involve determining the type of data to be collected and establishing guidelines for analysing and evaluating that data. A mixed method approach is chosen, with a greater emphasis on qualitative aspects due to the nature of interpreting standards and establishing procedures. The developed framework is presented using tables that outline the required data inputs for reporting actual demands, spurious trips, failures of other barriers, and SIS element failures. Failure report templates are provided, emphasizing the importance of identifying root causes and categorizing failures into Safe or Dangerous failures, as well as Undetected or Detected. The reliability assessment involves comparing actual performance data against the criteria defined in the Safety Integrity Requirements that have been established for the SIS, based on the outcome of the risk assessment. Different risk assessment techniques, such as Layer of Protection Analysis, Fault tree analysis, and risk matrices, are presented in this context, while key performance indicators like demand rates and failure rates are explored to highlight their role in verifying SIS performance. The established framework, designed for the ESS to execute safety functions at Safety Integrity Level 2, is versatile and can serve as a robust foundation for the development of future Functional Safety projects within the organisation and can be applied to other SISs with different Safety Integrity level targets. The study concludes by addressing challenges associated with reliability and various data sources, such as human error and lack of functional safety training, emphasizing the significance of comprehending functional safety when operating with data of SISs

Development and certification of mixed-criticality embedded systems based on probabilistic timing analysis

An increasing variety of emerging systems relentlessly replaces or augments the functionality of mechanical subsystems with embedded electronics. For quantity, complexity, and use, the safety of such subsystems is an increasingly important matter. Accordingly, those systems are subject to safety certification to demonstrate system's safety by rigorous development processes and hardware/software constraints. The massive augment in embedded processors' complexity renders the arduous certification task significantly harder to achieve. The focus of this thesis is to address the certification challenges in multicore architectures: despite their potential to integrate several applications on a single platform, their inherent complexity imperils their timing predictability and certification. Recently, the Measurement-Based Probabilistic Timing Analysis (MBPTA) technique emerged as an alternative to deal with hardware/software complexity. The innovation that MBPTA brings about is, however, a major step from current certification procedures and standards. The particular contributions of this Thesis include: (i) the definition of certification arguments for mixed-criticality integration upon multicore processors. In particular we propose a set of safety mechanisms and procedures as required to comply with functional safety standards. For timing predictability, (ii) we present a quantitative approach to assess the likelihood of execution-time exceedance events with respect to the risk reduction requirements on safety standards. To this end, we build upon the MBPTA approach and we present the design of a safety-related source of randomization (SoR), that plays a key role in the platform-level randomization needed by MBPTA. And (iii) we evaluate current certification guidance with respect to emerging high performance design trends like caches. Overall, this Thesis pushes the certification limits in the use of multicore and MBPTA technology in Critical Real-Time Embedded Systems (CRTES) and paves the way towards their adoption in industry.Una creciente variedad de sistemas emergentes reemplazan o aumentan la funcionalidad de subsistemas mecánicos con componentes electrónicos embebidos. El aumento en la cantidad y complejidad de dichos subsistemas electrónicos así como su cometido, hacen de su seguridad una cuestión de creciente importancia. Tanto es así que la comercialización de estos sistemas críticos está sujeta a rigurosos procesos de certificación donde se garantiza la seguridad del sistema mediante estrictas restricciones en el proceso de desarrollo y diseño de su hardware y software. Esta tesis trata de abordar los nuevos retos y dificultades dadas por la introducción de procesadores multi-núcleo en dichos sistemas críticos: aunque su mayor rendimiento despierta el interés de la industria para integrar múltiples aplicaciones en una sola plataforma, suponen una mayor complejidad. Su arquitectura desafía su análisis temporal mediante los métodos tradicionales y, asimismo, su certificación es cada vez más compleja y costosa. Con el fin de lidiar con estas limitaciones, recientemente se ha desarrollado una novedosa técnica de análisis temporal probabilístico basado en medidas (MBPTA). La innovación de esta técnica, sin embargo, supone un gran cambio cultural respecto a los estándares y procedimientos tradicionales de certificación. En esta línea, las contribuciones de esta tesis están agrupadas en tres ejes principales: (i) definición de argumentos de seguridad para la certificación de aplicaciones de criticidad-mixta sobre plataformas multi-núcleo. Se definen, en particular, mecanismos de seguridad, técnicas de diagnóstico y reacción de faltas acorde con el estándar IEC 61508 sobre una arquitectura multi-núcleo de referencia. Respecto al análisis temporal, (ii) presentamos la cuantificación de la probabilidad de exceder un límite temporal y su relación con los requisitos de reducción de riesgos derivados de los estándares de seguridad funcional. Con este fin, nos basamos en la técnica MBPTA y presentamos el diseño de una fuente de números aleatorios segura; un componente clave para conseguir las propiedades aleatorias requeridas por MBPTA a nivel de plataforma. Por último, (iii) extrapolamos las guías actuales para la certificación de arquitecturas multi-núcleo a una solución comercial de 8 núcleos y las evaluamos con respecto a las tendencias emergentes de diseño de alto rendimiento (caches). Con estas contribuciones, esta tesis trata de abordar los retos que el uso de procesadores multi-núcleo y MBPTA implican en el proceso de certificación de sistemas críticos de tiempo real y facilita, de esta forma, su adopción por la industria.Postprint (published version

Towards Standardisation Measures to Support the Security of Control and Real-Time Systems for Energy Critical Infrastructures

This report outlines the context for control and real time systems vulnerability in the energy sector, their role in energy critical infrastructures and their emerging vulnerabilities as they were put in light by some recent episodes. Then it provides a survey on the current efforts to set up reference frameworks addressing the broad issue of supervisory and control systems security. It discusses the role of standards and outlines the reference approaches in that respect. The current attitude of Europe towards the issue of control systems security is discussed and compared with the US situation, based on a stakeholder consultation, and gaps and challenges are outlined. A set of recommendations for policy measures to address the issue is given.JRC.DG.G.6-Security technology assessmen

Variability management in process families through change patterns

© 2016. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/Context: The increasing adoption of process-aware information systems together with the high variability in business processes has resulted in collections of process families. These families correspond to a business process model and its variants, which can comprise hundreds or thousands of different ways of realizing this process. Managing process variability in this context can be very challenging, labor-intensive, and error-prone, and new approaches for managing process families are necessary. Objective: We aim to facilitate variability management in process families, ensure process family correctness, and reduce the effort needed for such purposes. Method: We have derived a set of change patterns for process families from variability-specific language constructs identified in the literature. For validation, we have conducted a case study with a safety standard in which we have measured the number of operations needed to model and evolve the variability of the standard with and without the patterns. Results: We present 10 change patterns for managing variability in process families and show how they can be implemented. The patterns support the modeling and evolution of process families and ensure process family correctness by automatically introducing and deleting modeling elements. The case study results show that the application of the defined change patterns can reduce the number of operations when modeling a process family by 34% and when evolving it by 40%. Conclusions: The application of the change patterns can help in effectively modeling and evolving large and highly-variable process families. Their application can also considerably reduce variability management effort. (C) 2016 Elsevier B.V. All rights reserved.This work has been developed with the financial support of Spanish Ministry of Economy and Competitiveness under the project SMART-ADAPT TIN2013-42981-P. We also want to thank Barbara Weber and Manfred Reichert for their valuable input and feedback on the design and development of the set of change patterns for process families.Ayora Esteras, C.; Torres Bosch, MV.; De La Vara González, JL.; Pelechano Ferragud, V. (2016). Variability management in process families through change patterns. Information and Software Technology. 74:86-104. https://doi.org/10.1016/j.infsof.2016.01.007S861047

Safety and reliability improvement of valves and actuators in the offshore oil and gas industry

Valve failure is a major risk and a costly phenomenon in the offshore sector of the oil and gas industry. It results in severe negative consequences, such as a loss of assets, a loss of production due to plant shutdowns, and health, safety, and environmental (HSE) issues, such as hydrocarbon (oil and gas) spillage. Improving the safety and reliability of the valves and connected actuators is necessary to limit the occurrence of failure. This paper focuses on three aspects of improving valve and actuator reliability: material selection, design optimization, and boosting the safety integrity level (SIL). The first and second aspects are applicable only to valves, but the third targets both valves and actuators. Using value engineering as a systematic material selection approach shows that 25 Cr super duplex is an optimum material for valves in process services, such as valves for hydrocarbons and chemicals, if the hydrogen sulfide content in the oil is below the limit given in ISO 15156. A case study using a wall thickness and weight reduction approach—according to ASME sec.VIII instead of ASME B16.34—on large, heavy oil export pipeline ball valves is reviewed in this paper. A finite element analysis has been performed to ensure that the thickness of the valve is sufficient to withstand pipeline loads. Insufficient valve thickness can jeopardize the mechanical integrity of a valve and causes valve failure. SIL calculation is a major step in improving the safety and reliability of safety critical valves. A method of SIL calculation is implemented as per the IEC 61508 standard for oil export pipeline valves with an emergency shutdown function. Utilizing leakage monitoring and partial stroke testing increases the SIL along with safety and reliability.publishedVersio

Estimating Impact and Frequency of Risks to Safety and Mission Critical Systems Using CVSS

Many safety and mission critical systems depend on the correct and secure operation of both supportive and core software systems. E.g., both the safety of personnel and the effective execution of core missions on an oil platform depend on the correct recording storing, transfer and interpretation of data, such as that for the Logging While Drilling (LWD) and Measurement While Drilling (MWD) subsystems. Here, data is recorded on site, packaged and then transferred to an on-shore operational centre. Today, the data is transferred on dedicated communication channels to ensure a secure and safe transfer, free from deliberately and accidental faults. However, as the cost control is ever more important some of the transfer will be over remotely accessible infrastructure in the future. Thus, communication will be prone to known security vulnerabilities exploitable by outsiders. This paper presents a model that estimates risk level of known vulnerabilities as a combination of frequency and impact estimates derived from the Common Vulnerability Scoring System (CVSS). The model is implemented as a Bayesian Belief Network (BBN)