The risk-based approach is an enhanced system of the regulation and standardization of Electromagnetic compatibility (EMC) in electronic devices before their commercialization. EMC is essential for ensuring the safety, performance, and quality of electronic devices. However, achieving and maintaining EMC presents a significant challenge due to the rapid development of new products with evolving technologies and features. It is often assumed that if a device meets the electromagnetic emission and immunity levels defined by the EMC standards, it has been tested against worst-case electromagnetic disturbance phenomena. However, this is usually not the case, and devices frequently face more severe electromagnetic environments than anticipated in real life and malfunction. Additionally, product technology can evolve faster than EMC standards and therefore, relying solely on immunity testing is no longer sufficient to ensure EMC. While conventional testing methods specified in EMC standards are essential for assessing the EM immunity of electrical and electronic equipment, they are often inadequate for ensuring safety-critical systems will maintain acceptable failure levels throughout their entire expected lifecycle. In fields such as transportation, medicine, and defense, technological advancements have led to the integration of sophisticated features into a wide range of complex systems, which are more electrified, connected, and automated than their predecessors, resulting in increased complexity and a lack of comprehensive system understanding. Achieving EMC is essential for these systems to prevent potential hazards hazards caused by electromagnetic interference (EMI) that could compromise safety, security, and reliability. Many EMC experts and scientists argue that the current rule-based EMC testing approach is insufficient for addressing these challenges. Some of the reasons include:
Only one EM disturbance is tested at a time Normal EMC test methods are designed for accuracy and repeatability, and not to simulate real life The effects of the physical environment are not considered by normal EMC testing Ageing is not considered by normal immunity testing The maximum test level is not necessarily the worst These are just a few reasons why the current rule-based approach, which mandates compliance with relevant EMC standards and regulations, may be inadequate for complex systems. In addition to potentially compromising system attributes like safety and security, this approach can lead to financial losses due to launch delays caused by EMC issues identified later in the development process. However, due to budget constraints on money, time, and equipment for testing immunity and emissions, it is impractical to conduct more extensive testing than what is currently done by system manufacturers and component suppliers. Therefore, in addition to complying with existing standards, it is crucial to perform a comprehensive risk assessment and implement risk mitigation measures to prevent unacceptable consequences for stakeholders. The European Commission has recognized that many companies only meet the minimum requirements of harmonized standards to demonstrate EMC compliance. This prompted the release of the Blue Guide, the RED Guide, and most recently, the Guide for the EMC Directive, all of which emphasize a risk-based approach. The key points related to this "risk-based approach" outlined in these guides can be summarized as follows:
Harmonized standards do not replace legally binding essential requirements Even when using harmonized standards, the manufacturer remains fully responsible for assessing the risks associated with their product Conformity assessment requires technical documentation and must include a thorough risk analysis The EMC assessment must consider all normal intended operating conditions and configurations of the equipment. The challenges involved in implementing a risk-based approach should not be underestimated. Traditionally, each device was assessed individually, with the goal of ensuring its own protection against EMI using arbitrary sets of standardized values as a reference. However, the design philosophy has fundamentally shifted towards considering scenarios that ensure a device functions safely within its intended electromagnetic environment throughout its lifetime. This approach requires considering every possible interaction with other devices across various settings. The change goes beyond merely re-enforcing existing EMI protections; it involves understanding new electromagnetic environments of use, adapting to them, and inventing protective solutions to address emerging EMI issues, all while maintaining the key design characteristics of the device. It also focuses on ensuring long-term resilience and reliability in face of the constantly changing and increasingly complex EMI scenarios. Given these factors, the "risk-based approach" should be the default practice.
Medical device risk management concepts The law demands a risk-based approach rather than the conventional, rule-based approach. The EMCD (the EMC directive - the law) and the Blue Guide, which covers the implementation of EU product rules, require an EMI risk-based approach for any new equipment. Similarly, the specific regulations for medical equipment (MDR and IEC 60601-1-2) also refer to a risk-based approach. The Medical Device Regulation (MDR) 2017/745 outlines General Safety and Performance Requirements (GSPR) that medical device manufacturers must meet. Anned I of the MDR specifies EMC-related GSPR in Articles 14.2(b), 18.5, 18.6, and 23.4(s). These requirements ensure that medical devices remain safe and effective in the presence of EMI risks caused by electromagnetic disturbances. Ultimately, regulatory bodies review and confirm that EMC-related GSPR continue to perform satisfactorily, ensuring the safety and effectiveness of medical devices. Medical device EMC risk management includes various key terms such as electromagnetic disturbances, electromagnetic compatibility, EM environment, EM emission, Immunity (to a disturbance), risk, hazard, harm, hazardous situation, risk analysis, risk evaluation, risk control, residual risk, basic safety, essential performance, severity, risk management file, intended use, benefit, etc.
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