Not by it self but a system of redundant PC's with RAID type memory backup could.
I have only worked on one project where IEC61508 was contractually called out requiring a system that was SIL Level 3. One of the functional safety functions was a fire detection and emergency response function for underground stations. Upon detection of a fire the system had to assess where the fire was, turn on the appropriate exhaust fans and in the correct detection so as to not pump smoke into the patron areas. It then had to stop and reverse the direction of the inbound escalators and play the appropriate message over the PA system to direct the patrons out of the station. The only way to meet the SIL Level 3 requirements could be met was with a highly redundant and distributed system with back-up power for the AC mains. Another safety function that was required to meet IEC61508 was patron emergency phones. This was a system that when a patron hit the emergency call for help button on any patron emergency phone through the system and video camera would aim at the phone and the system would route the call to the security desk at the operations center and bring up the appropriate camera on the main security monitor. The phone would always be a single point of failure and they just aren't reliable enough to meet SIL Level 3. To meet the customer requirements we had to define a PM schedule that required that all the patron emergency phones in the system be tested on a monthly basis. These are somewhat unique applications of 61508 but it does demonstrate how the standard is applied to a system and the risk mitigation steps to meet a safety integrity level. The majority System Safety work I have been involved with has been per MIL-STD-882. Dave Clement From: "[email protected]" <[email protected]> To: Jim Eichner <[email protected]> Cc: [email protected] Sent: Tuesday, October 28, 2008 5:02:51 PM Subject: RE: Functional Safety and the LVD LVD and 61508-3 would be entertaining. Does anyone think that any of the commonm computer OS's could pass even SIL 1 requirements? And how do you get a "Proven in Use" Compiler if Yet to be Proven compilers cannot be used? Or my other favorite is SIL X anything for consumer use. Who wants to admit 10^-X fatalities per year caused by their device? For Refineries and similar applications the standard makes sense to me. The cumulative probabil ity that a valve will open when it shouldn't makes sense as a SIL class. But to define even just the valve itself to a SIL I think only adds to confusion and potential mistakes. Such as a valve failing to fully close, releasing product into a dyked area, has a different consequence from the valve casing rupturing in a manned control area. "Jim Eichner" <Jim.eichner@XANT To: <[email protected]> REX.COM> cc: Sent by: Subject: RE: Functional Safety and the LVD [email protected] 10/28/2008 03:57 PM Ok but does that mean it won’t ever get published under the LVD? Maybe the only answer is “never say never”. Jim Eichner, P.Eng. Compliance Engineering Manager Xantrex Technology Inc. phone: (604) 422-2546 mobile: (604) 418-8472 e-mail: [email protected] web: www.xantrex.com Confidentiality Notice: This email message, including any attachments, is for the sole use of the intended recipient(s) and may contain confidential and privileged information. Any unauthorized review, use, disclosure or distribution is prohibited. If you are not the intended recipient, please contact the sender by reply e-mail and destroy all copies of the original message. From: David Clement [mailto:[email protected]] Sent: Monday, October 27, 2008 4:03 PM To: Jim Eichner; [email protected] Subject: Re: Functional Safety and the LVD 61508 is not a product standard. It relates to systems that provide System Safety where a portion of the system is electrical, electronic, or programmable. System Safety as a discipline looks at the severity of hazards that are present if something fails to perform as designed, the likely hood of it occurring, assessing if the risk is acceptable and if its not take mitigation steps to reduce the risk. 61508 provides special considerations when the mitigation is provided by Electrical, Electronic or Programmable. For example; It has guidance on the software development rigor necessary for the different Safety Integrity Levels. An RCD device provides a safety function for sure but a single device is explicitly not covered. Below is an excerpt from the standard scope. does not cover E/E/PE systems where – a single E/E/PE system is capable of providing the necessary risk reduction, Dave Clement From: Jim Eichner <[email protected]> To: [email protected] Sent: Monday, October 27, 2008 11:14:06 AM Subject: RE: Functional Safety and the LVD Those systems are covered, but there’s nothing that excludes products. Take for example an RCD device. Clearly its function is safety-related. Why wouldn’t the 61508 series be relevant? Jim Eichner, P.Eng. Compliance Engineering Manager Xantrex Technology Inc. e-mail: [email protected] web: www.xantrex.com Any opinions expressed are those of my invisible friend. Confidentiality Notice: This email message, including any attachments, is for the sole use of the intended recipient(s) and may contain confidential and privileged information. Any unauthorized review, use, disclosure or distribution is prohibited. If you are not the intended recipient, please contact the sender by reply e-mail and destroy all copies of the original message. From: David Clement [mailto:[email protected]] Sent: Saturday, October 25, 2008 2:12 PM To: Jim Eichner; [email protected] Subject: Re: Functional Safety and the LVD 61508 deals with electrical, electronic and program devices and systems that provide safety such as rail road signaling, safety shut down systems in power plants, machinery interlocks. It has several in depth sections on software that is used in systems that provide functional safety. I don't see it being called out as part of a product safety directive. Dave Clement From: Jim Eichner <[email protected]> To: [email protected] Sent: Friday, October 24, 2008 1:44:53 PM Subject: Functional Safety and the LVD A search of the latest list of standards under the LVD does not turn up any hits on EN61508, yet it would seem natural for this standard to be considered relevant under the LVD. I'm not looking for the added work that would imply, but I do need to know if it's coming. Any thoughts or inside knowledge if this is coming our way? Thanks, Jim Eichner, P.Eng. Compliance Engineering Manager Xantrex Technology Inc. e-mail: [email protected] web: www.xantrex.com Any opinions expressed are those of my invisible friend. Confidentiality Notice: This email message, including any attachments, is for the sole use of the intended recipient(s) and may contain confidential and privileged information. Any unauthorized review, use, disclosure or distribution is prohibited. If you are not the intended recipient, please contact the sender by reply e-mail and destroy all copies of the original message. - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. 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