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Paper 2: Why embrace the concept of the Safety Requirements Specification?
Institute of Measurement and Control – Functional Safety 2016
8
requirements only, be driven by the needs of the process and specify
requirements not solutions. Contributors to the SRS should imagine themselves
in 10 years time asking "why"?
Why embrace the concept of the Safety Requirements
Specification?
The SRS is a mandatory requirement of IEC 61511. However, for it to be an
effective tool in enhancing functional safety and the safety of hazardous
processes, we need good reasons to dedicate the required time and effort in its
production. The question posed by this paper can be answered with a long list
of points but let’s focus on two.
From experience we can confidently state that developing a safety requirement
specification which focusses on the process and safety functions will lead to a
different solution to that expected.
Better understood hazards lead to better designed and safer solutions.
We need to maintain the connection between the SIS at any point in the safety
lifecycle, with the design intent established at the beginning. The ability to
answer as many questions “why?” will be crucial to making the right decision in
the future.
If specifications (the solution) are not linked to requirements (the
process) then their importance cannot be judged or risk assessed by
others for ---- the ------------ whole ----------------------------- lifecycle.