GB/Z 37150-2018Guide of Risk Assessment of EMC Reliability (English PDF)

3.1 Risk assessment

The whole process of risk identification, risk analysis and risk assessment.

3.2 Risk level

The levels of risk assessment elements when making the risk assessment.

The main roles of EMC risk assessment include:

--- Identify the EMC risk and potential impact under specific tarts of equipment, system or engineering site;

--- Increase understanding of EMC risk to facilitate the correct selection of risk response strategies;

--- Identify the major factors that contribute to EMC risk and the weak links of EMC risk in equipment, system or engineering site;

--- Analyze the EMC risk and uncertainties;

--- Conducive to establish design principles;

--- Help to determine whether the EMC risk is acceptable;

--- Conducive to prevent EMC problems through additional measures;

--- May be used as an input to risk management, and may be effectively linked to other components of the risk management process.

7.4.2 Risk level and classification of EMC assessment elements

EMC risk level is the result of risk analysis. It may be classified according to the degree of influence of individual elements. It may also be classified according to the qualitative, semi-quantitative and quantitative analysis methods. It may be divided into “Level-I”,

“Level-II”, “Level-III” according to the qualitative analysis method. The divided levels shall be typical, with no overlapping parts between the levels. The divided levels are as follows:

a) Level-I: When the requirements of risk assessment elements are not met under certain conditions, it shall definitely lead to failure (if the test fails);

b) Level-II: When the requirements of the risk assessment elements are not met, there shall be other clear remedies to avoid failure;

c) Level-III: When the requirements are not met, it does not necessarily lead to test failure.

Some specific risk elements obtained in the EMC risk analysis may not exist in the assessment object. These risk elements may be divided into the following two types according to their impacts on the consequences:

a) Type-a: If there is no relevant information (required) about the risk elements in the product, then the risk level of such risk elements is considered to be highest,

Level-I;

b) Type-b: If there is no relevant information (not required) about the risk elements in the product, then the risk level of such risk elements is considered to be lowest,

Level-III.

--- The obtained results shall be able to deepen the understanding of the nature of the risks and how to deal with them;

--- Shall be used in a traceable, repeatable and verifiable manner.

Explain the reasons for choosing a technique in terms of relevance and applicability.

When using different techniques to obtain the assessment results, the used techniques and results shall be comparable.

The example of risk assessment tools can refer to Appendix B.

A.2.3 Supervision and inspection

Risk assessment process emphasizes the environmental and other factors of the equipment, system and engineering site; these factors may change over time, and may alter or invalidate the risk assessment results. These factors shall be identified and continuously supervised and inspected; so that update the information input of the new risk assessment, and conduct the dynamic assessment against the risk.

Data monitored to improve the risk assessment shall be identified and collected. The effects of the risk control measures shall also be monitored and recorded; so that provide data for risk analysis. The responsibility for the establishment and inspection of evidence and documents shall be clarified.

As part of the EMC risk management process, EMC risk and control shall be supervised and inspected regularly to confirm:

--- Assumptions about EMC risks remain valid;

--- Assumptions for which the EMC risk assessment is based on, including the internal and external environment, remain valid;

--- Expected results being achieved;

--- Results of EMC risk assessment are in line with practical experience;

--- EMC risk response is effective.

A.2.4 Communication and recording

A successful EMC risk assessment relies on effective communication and negotiation with the manufacturer/user of the equipment, system and engineering site, as well as the technical capabilities of the EMC risk assessment implementer.

The involvement of EMC risk assessment stakeholders in the EMC risk assessment management process helps:

--- Development of communication plans;

Appendix B (Informative)

Example of Assessment Tools of EMC Risk Assessment

B.1 Overview

This Appendix gives several methods for EMC risk assessment. The selection principle of the risk assessment method shall analyze whether it is suitable for the relevant equipment, system and engineering site from the perspective of applicability; combine with EMC related experience and EMC test results for risk result to verify the correctness of the risk assessment.

B.2 Risk index method

B.2.1 Overview

The risk index method is an effective tool for classifying the risk levels and is a semi- quantitative assessment of risk. The risk index is an estimated value derived by a sequential scale scoring method.

NOTE: A variable measurement scale that has the nature of nominal data and can show the order or level of data.

A suitable index model may be designed to summarize the plus, subtraction, multiplication and/or division of the scores of each EMC risk element. Once the scoring system is established, the model shall be used on the known equipment, system and engineering site; and compare with the EMC test results to confirm its effectiveness.

B.2.2 Advantages and limitations

The advantages of the risk index method include:

--- The risk index method may provide an effective level-classification tool;

--- A variety of factors affecting the level may be integrated to the analysis of the risk level.

Limitations include:

If the process (mode) and its output results fail to be well-confirmed, it may make the results meaningless.

B.3 Risk matrix method

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