GB/T 20438.5-2017 English PDF (GBT20438.5-2017)

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GB/T 20438.5-2017: Functional safety of electrical/electronic/programmable electronic safety-related systems -- Part 5: Examples of methods for the determination of safety integrity levels
GB/T 20438.5-2017
Functional safety of electrical/electronic/programmable electronic safety-related systems-Part 5. Examples of methods for the determination of safety integrity levels
ICS 25.040
N10
National Standards of People's Republic of China
Replace GB/T 20438.5-2006
Electrical/electronic/programmable electronic safety related systems
Functional safety Part 5. Determining safety integrity
Level method example
systems-Part 5. Examplesofmethodsforthedeterminationof
(IEC 61508-5.2010, IDT)
2017-12-29 released.2018-07-01 implementation
General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China
China National Standardization Administration issued
Content
Foreword I
Introduction II
1 range 1
2 Normative references 3
3 Definitions and abbreviations 3
Appendix A (informative) Risk and Safety Integrity - General Concept 4
Appendix B (informative) Method selection for determining safety integrity level requirements 14
Appendix C (informative) ALARP and the concept of tolerable risk 16
Appendix D (informative) Determining the safety integrity level - a quantitative method 19
Appendix E (informative) Determination of safety integrity level - risk map method 21
Appendix F (informative) Semi-quantitative method (LOPA) using protective layer analysis 27
Appendix G (Informative Appendix) Determination of Safety Integrity Level - A Qualitative Approach - Dangerous Event Severity Matrix 31
Reference 33
Figure 1 Overall framework of GB/T 20438 2
Figure A.1 Risk Reduction. General Concept (Low Demand Operating Mode) 7
Figure A.2 Risk and Safety Integrity Concept 7
Figure A.3 Risk of demanding applications Figure 8
Figure A.4 Risk of continuous mode operation Figure 9
Figure A.5 Common Cause Failure (CCF) Example 10 of EUC Control System Components and E/E/PE Safety-Related System Components
Figure A.6 Common cause failure between two E/E/PE safety-related systems 11
Figure A.7 Security requirements for E/E/PE safety-related systems and other risk reduction measures 12
Figure C.1 Tolerable risk and ALARP 16
Figure D.1 Example of Safety Integrity Assignment - Safety Related Protection System 20
Figure E.1 Risk Map. General Scheme 23
Figure E.2 Risk Map - Example (only general principles are explained) 24
Figure G.1 Dangerous Event Severity Matrix - Example (only general principles are indicated) 32
Table C.1 Example of accident risk classification 17
Table C.2 Explanation of risk levels 18
Table E.1 Examples of data related to the risk map (Figure E.2) 24
Table E.2 Calibration example for the general risk map 25
Table F.1 LOPA Report 28
Foreword
GB/T 20438 "Functional Safety of Electrical/Electronic/Programmable Electronic Safety-Related Systems" is divided into seven parts.
--- Part 1. General requirements;
--- Part 2. Requirements for electrical/electronic/programmable electronic safety related systems;
--- Part 3. Software requirements;
--- Part 4. Definitions and abbreviations;
--- Part 5. Examples of methods for determining the safety integrity level;
--- Part 6. Application guide for GB/T 20438.2 and GB/T 20438.3;
--- Part 7. Overview of techniques and measures.
This part is the fifth part of GB/T 20438.
This part is drafted in accordance with the rules given in GB/T 1.1-2009.
This part replaces GB/T 20438.5-2006 "Safety of electrical/electronic/programmable electronic safety related systems - Part 5.
Example of a method for determining the safety integrity level. Compared with GB/T 20438.5-2006, the main technical changes are as follows.
--- Increased method choices for determining safety integrity level requirements; (see Appendix B);
--- Increased risk analysis method. semi-quantitative method (LOPA) using protective layer analysis (see Appendix F).
This section uses the translation method equivalent to the functional safety of IEC 61508-5.2010 "Electrical/Electronic/Programmable Electronic Safety-Related Systems
Part 5. Example of a method for determining a safety integrity level.
This part was proposed by the China Machinery Industry Federation.
This part is under the jurisdiction of the National Industrial Process Measurement Control and Automation Standardization Technical Committee (SAC/TC124).
This section drafted by. Mechanical Industry Instrumentation Institute of Integrated Technology and Economics, Beijing Guodian Zhishen Control Technology Co., Ltd., Hangzhou
Holly Automation Co., Ltd., Beijing Labor Protection Science Research Institute, Wind Control (Beijing) Engineering Technology Co., Ltd., Beijing Union Puken
Cheng Technology Co., Ltd., Shanghai Zhonghu Electronics Co., Ltd., Siemens (China) Co., Ltd.
The main drafters of this section. Shi Xueling, Xiong Wenze, Qi Jianghong, Chen Yong, Yang Liu, Xiao Songqing, Zhou Youzhen, Mei Hao, Huang Jinsong, Lu Yi, Feng Xiaosheng,
Luo An, Gu Yu, Li Jia, Tian Yucong, Zuo Xin, Jiang Xuelian, Bai Yan.
The previous versions of the standards replaced by this section are.
---GB/T 20438.5-2006.
introduction
Systems consisting of electrical and electronic components have performed their safety functions in many applications for many years. Computer-based system
Systems (generally referred to as programmable electronic systems) are used in their application areas to perform non-secure functions and are increasingly used to perform safety functions.
can. If computer technology is to be used safely and effectively, the decision makers have sufficient guidance on security and the decision is based on this.
Sub-required.
GB/T 20438 for the implementation of safety functions consisting of electrical and/or electronic and/or programmable electronics (E/E/PE) components
A common approach to all activities of the system security lifecycle. The purpose of adopting a unified approach is to target all electricity
A consistent and reasonable technical approach is proposed for the underlying security-related systems. The main goal is to promote the standard based on GB/T 20438 series
The development of national standards for quasi-products and applications.
Note 1. Examples of product and application domain standards based on the GB/T 20438 series of standards are given in the references (see references [1], [2], [3]).
In many cases, a variety of different technologies are available (eg mechanical, hydraulic, pneumatic, electrical, electronic, programmable electronics)
The system is guaranteed to be safe. Therefore, various security policies have to be considered, not only considering the problems of all components in a single system (such as
Sensors, controllers, actuators, etc.), but also consider the combination of different safety-related systems. So when GB/T 20438 is concerned about electricity
At the same time as gas/electronic/programmable electronics (E/E/PE) safety-related systems, it also provides a framework within which other technologies are based.
Safety related systems can also be considered.
There are many potential dangers and risks in various application fields, and the complexity involved is different, so different applications are needed.
E/E/PE safety related system. For each specific application, the required security measures will be determined based on a number of factors for a particular application.
As a basic principle, GB/T 20438 can regulate these measures in the formulation of national standards and the revision of existing standards in future product and application fields.
GB/T 20438
--- Consider the overall safety life cycle, E/E/PE system safety involved when performing safety functions using E/E/PE systems
Lifecycle and phases of the software security lifecycle (eg initial concept, overall design, implementation, operation and maintenance to decommissioning);
--- Establish a framework that is robust enough to meet future development needs for rapidly evolving technologies;
--- Develop national standards for products and applications involving E/E/PE safety-related systems; in the box of GB/T 20438
Under the shelf, the development of national standards for products and applications should be highly consistent in the application and cross-application areas (eg
The principle, terminology, etc.; this will be both safe and economical;
--- To provide the functional security required for E/E/PE safety-related systems, and to provide a method for preparing safety requirements;
--- A risk-based approach to determining safety integrity requirements is adopted;
--- Introduce a safety integrity level that specifies the safety objectives of the safety functions to be performed by the E/E/PE safety-related system.
Sexual grade
Note 2. GB/T 20438 does not specify the safety integrity level requirements of each safety function, nor does it dictate how to determine the safety integrity level. But
Provides a framework and technical examples based on risk concepts.
--- Established the target failure amount of the E/E/PE safety-related system to perform safety functions, which are the same as the safety integrity level.
contact;
--- Establish a lower limit for the target failure amount when a single E/E/PE safety-related system performs safety functions. These E/E/
PE safety related systems operate on.
--- In the low demand operation mode, the average probability of dangerous failure when the lower limit is set to the requirement is 10-5;
--- In the high demand or continuous operation mode, the lower limit is set to the dangerous failure average frequency of 10-9/h.
Note 3. A single E/E/PE safety-related system is not necessarily a single-channel architecture.
Note 4. For non-complex systems, it is possible to achieve better target safety integrity through the design of safety-related systems. But for relatively complex systems (eg
Such as programmable electronic safety related systems, these limits represent the levels currently achievable.
--- Based on the experience and judgment gained in industrial practice, set requirements for avoiding and controlling systemic failures; even if systemicity occurs
The possibility of barriers is generally not quantifiable, but GB/T 20438 allows for a specific security function to be declared, ie if the standard
All the requirements in the meeting are met, and the target failure amount related to the safety function has been reached;
--- Introduced a systemic capability that indicates that a component is systematically safe when it meets the specified safety integrity level requirements
Confidence in integrity;
--- A variety of principles, techniques and measures to achieve functional safety of E/E/PE safety-related systems, but not explicitly lost
Effect - the concept of security. However, if it meets the requirements of the relevant provisions of the standard, the concept of "failure-safety" and "essence"
The "safe" principle may be applied and the adoption of these concepts is acceptable.
Electrical/electronic/programmable electronic safety related systems
Functional safety Part 5. Determining safety integrity
Level method example
1 Scope
1.1 This part of GB/T 20438 provides the following information.
--- The basic concept of risk and the relationship between risk and safety integrity (see Appendix A);
--- Provide a range of methods to determine the safety integrity level of E/E/PE safety related systems (see Appendix C, Appendix D, Appendix E,
Appendix F and Appendix G).
The method chosen should depend on the area of application and the specific environment in question. Appendix C, Appendix D, Appendix E, Appendix F and Appendix G
A qualitative and quantitative approach has been developed and the principles underlying the simplification have been simplified. Through these appendices, the general purpose of a series of methods is illustrated.
Rational, but does not provide clear calculations. If you use the method mentioned in the appendix, you need to inquire about the original material.
Note. For more information on the methods described in Appendix B and Appendix E, see references [5] and [8]. For a description of the additional methods, see
Reference [6].
1.2 GB/T 20438.1, GB/T 20438.2, GB/T 20438.3 and GB/T 20438.4 are basic safety standards, although it is not suitable
For low complexity E/E/PE safety related systems (see 3.4.3 of GB/T 20438.4-2017), but as a basic safety standard, each technology
The committee may use the relevant standards under the guidance of IEC Guide 104 and ISO /IEC Guide 51. GB/T 20438.1
GB/T 20438.2, GB/T 20438.3 and GB/T 20438.4 can also be used as independent standards. Horizontal safety of GB/T 20438
The function does not apply to medical devices covered by IEC 60601.
1.3 One of the responsibilities of the technical committees is to use basic safety standards wherever possible in the drafting of their standards. In this section,
The requirements, test methods or test conditions in this basic safety standard are only explicitly quoted or packaged in the standards drafted by these technical committees.
Applicable when applicable.
1.4 Figure 1 shows the overall framework of GB/T 20438, and at the same time clarifies that this part is implementing the functional safety of E/E/PE safety related systems.
The role of the process.
Figure 1 Overall frame of GB/T 20438
2 Normative references
The following documents are indispensable for the application of this document. For dated references, only dated versions apply to this article.
Pieces. For undated references, the latest edition (including all amendments) applies to this document.
GB/T 20438.1-2017 Functional safety of electrical/electronic/programmable electronic safety systems - Part 1. General requirements
(IEC 61508-1.2010, IDT)
GB/T 20438.4-2017 Functional safety of electrical/electronic/programmable electronic safety related systems - Part 4. Definitions and abbreviations
Language (IEC 61508-4.2010, IDT)
3 definitions and abbreviations
The definitions and abbreviations defined in GB/T 20438.4-2017 apply to this document.
Appendix A
(informative appendix)
Risk and Safety Integrity - General Concept
A.1 Overview
This appendix provides information on the basic concepts of risk and the relationship between risk and safety integrity.
A.2 necessary risk reduction
The necessary risk reduction (see 3.5.18 of GB/T 20438.4-201...