In recent years, ensuring effective electromagnetic coexistence between devices while maintaining safety and functionality has become progressively more challenging. This challenge is especially prominent within safety-critical applications, where any malfunction could result in severe consequences for both individuals and the environment.
Rule-based approach vs Risk-based approach
The traditional ‘rule-based’ approach for managing Electromagnetic Interference (EMI) relies on standards and compliance testing. However, the belief that individual apparatus meeting standards ensure collective compliance, especially in complex installations, can be dangerously incorrect [1]. A shift to a ‘risk-based’ approach aims to minimize inherent EMI risks systematically throughout the system lifecycle. This approach involves identifying hazards, assessing impacts, and implementing measures to mitigate or prevent adverse effects, ensuring a higher confidence level in protecting electrical and electronic systems against EMI.
Traditional approach to EMI risk analysis
Over the last years, many hazard-and-risk analysis techniques have been developed (e.g., Fault Tree Analysis or Failure Modes and Effects Analysis) [2]. However, no risk analysis methods have yet been developed to cover EMI issues, so it is necessary to choose the methods to use and adapt them to deal with EMI. Successful adaptation requires competency, skills, and expertise in safety engineering and real-life EMI [3].
Accidents can be caused by multiple independent failures
The traditional hazard analysis techniques rely on a linear chain of events accident model, assuming that accidents are caused by component failure and that increasing component reliability will prevent accidents (see Fig. 1). However, this assumption is no longer valid for the types of complex sociotechnical systems present in our society, in which emergent properties (e.g., safety, security) arise from the interactions between system components. Especially when the complexity increases, such interactions can only be analysed and understood by looking at the system as a whole instead of the sum of its parts.
A new approach: Systems thinking
The concept of systems thinking emerges as a guiding principle for navigating complexity. It considers the system as a whole by evaluating the interactions, relationships, and interdependencies within a system rather than isolating its individual components. Systems thinking encourages a shift from linear thinking to a holistic understanding, emphasizing the importance of exploring how various elements within a system influence one another (see Fig. 2).
Some unique aspects of systems thinking are [4]:
- Holistic approach. The system is treated as a whole, not as the sum of its parts.
- Emergent properties arise from relationships among the parts of the system, that is, by how they interact and fit together. These properties can only be treated adequately by considering all their technical and social aspects.
- Beyond Linear Chain Events: Unlike linear thinking, systems thinking considers non-linear causality, understanding that effects may not have straightforward relationships with their causes.
How can systems thinking be integrated into the EMI risk-based approach?
A system thinking approach to mitigate EMI-related hazards involves a comprehensive evaluation of the architecture of electronic systems and their susceptibility to electromagnetic interference. Some of the advantages of adopting a system thinking approach to deal with EMI are the following:
- Identification of Emergent Hazards. Systems thinking anticipates and identifies emergent hazards that may arise from the complex interactions and behaviors of interconnected components, providing a more proactive approach to risk mitigation.
- Life Cycle Consideration. The approach considers the entire life cycle of the system, addressing evolving EMI risks over time and adapting to changes in technology, usage patterns, and environmental conditions.
- Adaptability and Feedback Loops. The approach introduces feedback loops, allowing for continuous monitoring and adaptation to dynamic EMI conditions, fostering a more adaptive and responsive risk mitigation strategy.
- Improved Risk Prediction. By considering the system as a whole, systems thinking improves the ability to predict and assess potential EMI risks, including those that may not be apparent in a traditional, component-centric analysis.
- Traceability: It facilitates the identification of potential weaknesses in the system’s design. Moreover, by tracing causal relationships, it becomes easier to prioritize scenarios that could lead to significant losses, ensuring the allocation of resources to address the most critical issues. Additionally, traceability enhances decision-making by providing a clear and logical flow of information and decision points within the system, making it easier to implement appropriate control measures.
Overall, integrating systems thinking into the EMI risk-based approach brings numerous advantages. It enhances risk mitigation by identifying emergent hazards, considering the entire system life cycle, and introducing adaptability and feedback loops. This approach improves risk prediction, promotes proactive risk mitigation, optimizes resource allocation to critical areas, and enhances decision-making for effective risk management strategies.
References
[1] F. Leferink (2018), “Risk-based vs Rule-based Electromagnetic Compatibility in Large Installations,” 2018 IEEE 4th Global Electromagnetic Compatibility Conference (GEMCCON), Stellenbosch, South Africa, pp. 1-4, doi: 10.1109/GEMCCON.2018.8628505.
[2] ISO/TR 24971:2020 – Medical devices – Guidance on the application of ISO 14971, Geneva, Switzerland: ISO Std., 2020
[3] K. Armstrong (2011), “EMI Risk Analysis”, [Online]. Available : https://incompliancemag.com/article/emi-risk-analysis/
[4] N. G. Leveson (2012), “Engineering a Safer World: Systems Thinking Applied to Safety”. The MIT Press.