??? Document everything, not to catch them out but for future reference.
9.7.3 Relations with the Independent Safety Authority
The independent safety authority is appointed under a separate contract, usually by the body which will
own and operate the installed system, and is commercially and managerially independent of the design
and build team. He is there to assess the quality of the work being done on the safety case. Everything
in a safety-critical project contributes to the safety case. The role of testing is to provide evidence that
the safety targets have been met and the safety arguments (central to the safety case) are therefore valid.
The independent safety authority will therefore look for evidence of thorough testing to prove that the
system??™s reliability is as high as reasonably possible and every means has been employed to test with a
level of coverage as extensive as is reasonably possible. The question of engineering judgement is thus
paramount.
Do not expect guidance from the independent safety authority as to what is reasonable because that
would be exceeding his role. Look rather at:
??? The independence of the test team from the development team.
??? Relationship between the safety plan and the test plan.
??? The ability of the test team to access the safety log,7 the FMECA and the FTA, and see how the
testing of the various elements of a system critical to achieving a reliability target of the various
top event outcomes can be achieved.
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