Talk:Safety integrity level

Definition of SIL
This definition describes a 4-point SIL range. This is IEC code-specific. Other industries have different ranges. For example a 12-point range has been used in the nuclear industry. Riskimpact (talk) 03:20, 30 November 2007 (UTC)

The reference section does not give any examples of a SIL assessment. It is suggested that this section be added, with reference to the example of a dive life support system published on

http://www.deeplife.co.uk/or_files/SA_SIL_Assessment_241208.pdf  This is a particularly thorough document, illustrating each of the main methods and has had appropriate review,

and the HSE report:

M. Charlwood, S Turner and N. Worsell, UK Health and Safety Executive Research Report 216, “A methodology for the assignment of safety integrity levels (SILs) to safety-related control functions implemented by safety-related electrical, electronic and programmable electronic control systems of machines”, 2004. ISBN 0 7176 2832 9 /61508Assoc (talk) 19:30, 27 June 2009 (UTC)/

No comments received to the proposal above is taken as no objections. I have edited the article accordingly, adding the reference section. I also renamed the following section to refer to certification so it follows logically from the definitions, to enable the reader to move logically from definition of a SIL, how SILs are assigned, to how product SILs are certified. Links to the 61508 and other articles were added (there were no links previously, with risk this page is labelled as a stub without them). I did not put the 12 point range in, as it is historical and other standards use 5 points, numbering in reverse (e.g. 0 being the most onerous) etc - none of these I could find used the term Safety Integrity Level so hopefully would not be confused with a SIL. I did a general clean up of the grammar, and the 61508 subsection so the article flows logically. Please see the Edit summaries for more detail. Safety Engineer 09:11, 10 July 2010 (UTC) —Preceding unsigned comment added by 61508Assoc (talk • contribs)

SIL vs other industries' standards e.g. DO178 from aerospace
Do any readers have sufficient knowledge of both SIL and (eg) DO178 to be able to do a brief compare and contrast (or link to non-controversial ones that already exist)? — Preceding unsigned comment added by 80.229.247.139 (talk) 23:34, 23 April 2012 (UTC)
 * ff (at least to ) — The thread is about whether the two standards are applicable to different sectors, IEC 61508 about protection systems in the process industry, DO178 about control systems in the aerospace industry. My two cents on the difference: Protection systems mostly employ binary logic while control systems need continuous variables. --Rainald62 (talk) 11:01, 11 June 2018 (UTC)

System SIL v Device SIL - Discrepancies
I think a standard problem with the interpretation of SIL has occurred in the text. It states under Problems with the Use of SIL - "According to IEC 61508, the SIL concept must be related to the dangerous failure rate of a system, not just its failure rate or the failure rate of a component part, such as the software". But goes on to state "A device ... must meet the requirements for both categories to achieve a given SIL", "Certification schemes are used to establish whether a device meets a particular SIL" and "All the major components of HIPPS system shall be SIL-3 Approved". Most of the Certification to a Safety Integrity Level Section is written this way. This must be incorrect if the SIL concept relates to the failure rate of a system, and not just the device or component. Is this a correct interpretation? Does this need a re-write along these lines? 94.67.223.20 (talk) 09:21, 8 January 2014 (UTC)


 * I suspect that the quoted fragment of the IEC 61508 is not about scope (whether a SIL is applicable to parts of a system) but about which events shall (not) be taken into account.
 * "System" is almost meaningless, a thing consisting of parts. So a device is also a system. And there are cases where it is meaningful to assign a SIL requirement to a part of a system (equal, higher, or lower depending on the structure). On the other hand, many devices are tagged "SIL n" for mere marketing.
 * See also this high-level discussion. --Rainald62 (talk) 08:39, 11 June 2018 (UTC)

White Paper in External Links section has Restricted Access
The white paper listed in the External Links section (SIL Made Simple – White Paper presented at Valve World 2010) has some sort of restricted access. When I click on it (even while logged into Google with a valid Gmail account) it gives me a page that says "You need permission. Want in? Ask the owner for access, or switch to an account with permission. Learn more...". I don't think this is probably an appropriate way to share a page like that and wonder if it should be removed, or moved. PeterHansen (talk) 16:46, 8 July 2015 (UTC)

Source 3 does not exist
The source CASS Scheme, Conformity Assessment of Safety Systems, http://www.cass.uk.net/ is none existent. — Preceding unsigned comment added by Benbehr (talk • contribs) 09:17, 12 May 2022 (UTC)