I thought some PSTC subscribers (especially any involved in safety systems that depend at least in part on software or electronics) might be interested in this. The IEC has recently (Dec 2001?) posted an FAQ for IEC 61508, Functional safety of electrical/electronic/programmable electronic safety-related systems.
http://www.iec.ch/61508/ It is not a substitute for the standard (which has seven parts, total about 500 pages). The FAQ is only about 18 pages. Much better to browse the hyperlinked FAQ, but I have pasted a few quotes below anyway. best regards, glyn PS: Season's Greetings to you all. Glyn R. Garside TUV Rheinland of North America, Inc. (Chicago Office) 1945 Techny Rd, Unit 4, NORTHBROOK, IL 60062-5357, USA http://www.us.tuv.com TEL +1-847-562-9888 ext 25 Nationally Recognized Test Laboratory -- ANSI, UL -- CSA, SEMI EU Notified & Competent Body -- CE, EN -- ISO, IEC, CB-scheme Safety, EMC, Machinery, Pressure, Quality, Ergonomics, Automotive, Medical, Telecom. --------------------------------------------------------- [Extracts from http://www.iec.ch/61508/ ] "This document answers some Frequently Asked Questions (FAQs) about the international standard IEC 61508, Functional safety of electrical/electronic/programmable electronic safety-related systems. It has been compiled by SC65A/WG14 in collaboration with SC65A/MT12 and SC65A/MT13, the international committees responsible for the maintainance of IEC 61508. The answers to the questions are not intended to provide a definitive technical answer but rather to inform the new user to the standard." "IEC 61508 sets out a generic approach for all safety lifecycle activities for systems comprised of electrical and/or electronic and/or programmable electronic (E/E/PE) components that are used to perform safety functions. The seven part standard considers all relevant overall, E/E/PE system and software safety lifecycle phases (for example, from initial concept, through design, implementation, operation and maintenance to decommissioning). This unified approach has been adopted in order that a rational and consistent technical policy be developed for all electrically-based safety-related systems." "A1) What systems does IEC 61508 cover? IEC 61508 applies to safety-related systems when one or more of such systems incorporate electrical and/or electronic and/or programmable electronic (E/E/PE) devices. It covers possible hazards caused by failure of the safety functions to be performed by the E/E/PE safety-related systems, as distinct from hazards arising from the E/E/PE equipment itself (for example electric shock etc). It is generically based and applicable to all E/E/PE safety-related systems irrespective of the application. It is recognized that the consequences of failure could also have serious economic implications and in such cases the standard could be used to specify any E/E/PE safety-related system used for the protection of equipment or product. The scope of IEC 61508-1 gives more details. B4) What is a basic safety publication? Parts 1, 2, 3 and 4 of IEC 61508 are designated as IEC basic safety publications. This means that IEC Technical Committees will have to use these parts in the preparation of each of their own sector standards that has E/E/PE safety-related systems within its scope. IEC 61508 will therefore have far reaching implications across all IEC application sectors. Note that basic safety publication status does not apply in the context of low complexity E/E/PE safety-related systems or where the required safety integrity of the E/E/PE system is less than the lowest safety integrity level in IEC 61508. D3) What is a low complexity E/E/PE safety-related system? This is defined in 3.4.4 of IEC 61508-4 as an E/E/PE safety-related system, in which the failure modes of each individual component are well defined and the behaviour of the system under fault conditions can be completely determined. An example is a system comprising one or more limit switches, operating one or more contactors to de-energize an electric motor, possibly via interposing electromechanical relays. SOURCE: "This material may be freely reproduced, except for advertising, endorsement or commercial purposes. The International Electrotechnical Commission (IEC) must be acknowledged as the source. All such extracts are copyright of IEC, Geneva, Switzerland. All rights reserved." ------------------------------------------- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: [email protected] with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson: [email protected] Dave Heald [email protected] For policy questions, send mail to: Richard Nute: [email protected] Jim Bacher: [email protected] All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
