This discussion is locked.
You cannot post a reply to this discussion. If you have a question start a new discussion

Independant safety Assesment - Level of Independance?

What level of independance is required?



This came up in a recent conversation. It should be appropriate to the risk but at the back of my mind I seem to recal a table the went from



SIL4         Totally seperate organisation



Down to an individual from a different department.



Not having been involved directly in this area for some time is this still true?



Are the levels common or do they vary from Standard to Standard?



Regards
  • Former Community Member
    0 Former Community Member
    For SIL 4 I would expect an ISA to be contracted from a company that is completely independent of the company to be audited. In some cases the company providing the ISA need not be separate, but they must be able to show independence.




  • John, as far as I can see (and I only have EN 62061 and the previous version of EN 61508) the level of independence appears to vary greatly between the differing standards. The machinery market one I think is much more relaxed than the other sectors perhaps understandably. I dont think it actually mentions independance! Whereas I understand that in more onerous standards some (if not all) ask for

    SIL1 Independant engineer

    SIL2 Independant department

    SIL3 Independant Company

    SIL4 Know nothing about this!
  • Vinod

    Although I understand your sentiments, to meet the requirements of products marketed in Europe (as required by the CE mark) ALL a manufacturer needs to do for functional safety is to follow EN 62061 or EN ISO 13849. They do NOT have to meet any requirements of EN 61508 and as such dont have to apply the level of independance stated above even though many (if not all functional safety experts) would recommend these levels of independance.
  • On a related topic; the proportionality of assessment as well as independence is likely to be on the agenda at the forthcoming ISA WG Seminar ( in collaboration with the Safety Critical Systems Club) on 24th November in London.  Details of the event are on the SCSC website and also in the TPN,

    or use this link:

    http://scsc.org.uk/file/351/Nov-2015-ISA-WG-Programme-v3.pdf



    If you haven't booked to attend, then please do so soon.

    The event also includes a workshop - specifically looking at proportionality to help inform the WG publications which can be referenced as 'good practise'.