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Saturday, January 19, 2019
The Automation Safety Community Forum.
Questions About SIL 3 System Requirements
What are the requirements for SIL 3 system?

What are the requirements for SIL 3 system? My hardware and software is sil 3. Does it still require dual inputs and outputs to make it sil 3? Or with single input and output it is sil 3? kindly also refer some pdfs.

kindly explain sil 3 system requirements....

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As a CSE I know put it, a lot of people try to "buy" SIL systems. It can't be done. The responsibility for SIL is the plant owner's, and they need their own certified safety engineer to help with the plant design and safety analysis. Having SIL rated components is nowhere near enough, and there is no document that explains how to achieve a SIL rating, because it is very system specific.

Also beware overdoing it on specifying SIL ratings, as there is literally a thousand-fold increase in statistical safety per level, which doesn't come cheap. A good CSE can help avoid that pitfall and probably pay for themselves.

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Just because hardware (or software) is "suitable for use" in SIL3 does not automatically mean you have a SIL3 (or for that matter) any achieved SIL.

SIL applications have many requirements as to equipment selection , design of the safety function etc. I strongly recommend you get consulting or design services from someone who is trained / accredited in this area.

Several sources of training are available including ISA , exida and others.