Functional Safety

IEC 61508-7:2010 contains an overview of various safety techniques and measures relevant to IEC 61508-2 and IEC 61508-3.The references should be considered as basic references to methods and tools or as examples, and may not represent the state of the art. This edition constitutes a technical revision. It has been subject to a thorough review and incorporates many comments received at the various revision stages.

IEC 61508-6:2010 contains information and guidelines on IEC 61508-2 and IEC 61508 3. Annex A gives a brief overview of the requirements of IEC 61508-2 and IEC 61508-3 and sets out the functional steps in their application. Annex B gives an example technique for calculating the probabilities of hardware failure and should be read in conjunction with 7.4.3 and Annex C of IEC 61508-2 and Annex D. Annex C gives a worked example of calculating diagnostic coverage and should be read in conjunction with Annex C of IEC 61508-2. Annex D gives a methodology for quantifying the effect of hardware-related common cause failures on the probability of failure. Annex E gives worked examples of the application of the software safety integrity tables specified in Annex A of IEC 61508-3 for safety integrity levels 2 and 3. This second edition cancels and replaces the first edition published in 1998. This edition constitutes a technical revision. It has been subject to a thorough review and incorporates many comments received at the various revision stages.

IEC 61508-5:2010 provides information on the underlying concepts of risk and the relationship of risk to safety integrity (see Annex A); a number of methods that will enable the safety integrity levels for the E/E/PE safety-related systems to be determined (see Annexes C, D, E, F and G). The method selected will depend upon the application sector and the specific circumstances under consideration. Annexes C, D, E, F and G illustrate quantitative and qualitative approaches and have been simplified in order to illustrate the underlying principles. These annexes have been included to illustrate the general principles of a number of methods but do not provide a definitive account. Those intending to apply the methods indicated in these annexes should consult the source material referenced. This second edition cancels and replaces the first edition published in 1998. This edition constitutes a technical revision. It has been subject to a thorough review and incorporates many comments received at the various revision stages.

IEC 61508-4:2010 contains the definitions and explanation of terms that are used in parts 1 to 7 of the IEC 61508 series of standards. The definitions are grouped under general headings so that related terms can be understood within the context of each other. However, it should be noted that these headings are not intended to add meaning to the definitions. This second edition cancels and replaces the first edition published in 1998. This edition constitutes a technical revision. It has been subject to a thorough review and incorporates many comments received at the various revision stages. It has the status of a basic safety publication according to IEC Guide 104.

IEC 61508-3:2010 applies to any software forming part of a safety-related system or used to develop a safety-related system within the scope of IEC 61508-1 and IEC 61508-2; provides specific requirements applicable to support tools used to develop and configure a safety-related system within the scope of IEC 61508-1 and IEC 61508-2; requires that the software safety functions and software systematic capability are specified; establishes requirements for safety lifecycle phases and activities which shall be applied during the design and development of the safety-related software. These requirements include the application of measures and techniques, which are graded against the required systematic capability, for the avoidance of and control of faults and failures in the software; provides requirements for information relating to the software aspects of system safety validation to be passed to the organisation carrying out the E/E/PE system integration; provides requirements for the preparation of information and procedures concerning software needed by the user for the operation and maintenance of the E/E/PE safety-related system; provides requirements to be met by the organisation carrying out modifications to safety-related software; provides, in conjunction with IEC 61508-1 and IEC 61508-2, requirements for support tools such as development and design tools, language translators, testing and debugging tools, configuration management tools. This second edition cancels and replaces the first edition published in 1998. This edition constitutes a technical revision. It has been subject to a thorough review and incorporates many comments received at the various revision stages. It has the status of a basic safety publication according to IEC Guide 104.

IEC 61508-2:2010 applies to any safety-related system, as defined by IEC 61508-1, that contains at least:
- one electrical, electronic or programmable electronic element;
- applies to all elements within an E/E/PE safety-related system;
- specifies how to refine the E/E/PE system safety requirements specification, developed in accordance with IEC 61508-1, into the E/E/PE system design requirements specification;
- specifies the requirements for activities that are to be applied during the design and manufacture of the E/E/PE safety-related systems except software, which is dealt with in IEC 61508-3.
These requirements include the application of techniques and measures that:
- are graded against the safety integrity level, for the avoidance of, and control of, faults and failures;
- specifies the information necessary for carrying out the installation, commissioning and final safety validation of the E/E/PE safety-related system;
- provides requirements for the preparation of information and procedures needed by the user for the operation and maintenance of the E/E/PE safety-related systems;
- specifies requirements to be met by the organisation carrying out any modification of the E/E/PE safety-related systems.
This second edition cancels and replaces the first edition published in 1998. This edition constitutes a technical revision. It has been subject to a thorough review and incorporates many comments received at the various revision stages. It has the status of a basic safety publication according to IEC Guide 104.

IEC 61508-1:2010 covers those aspects to be considered when electrical/electronic/programmable electronic (E/E/PE) systems are used to carry out safety functions. A major objective of this standard is to facilitate the development of product and application sector international standards by the technical committees responsible for the product or application sector. This will allow all the relevant factors, associated with the product or application, to be fully taken into account and thereby meet the specific needs of users of the product and the application sector. A second objective of this standard is to enable the development of E/E/PE safety-related systems where product or application sector international standards do not exist. This second edition cancels and replaces the first edition published in 1998. This edition constitutes a technical revision. It has been subject to a thorough review and incorporates many comments received at the various revision stages. It has the status of a basic safety publication according to IEC Guide 104.