What does the Impact show?
From the simplified 1oo1 high pressure loop it can be seen that the
hardware integrity has reduced from SIL 2 to SIL1.
Potential impact of the C
PT
on the the risk reduction is in excess of an
order of magnitude.
It is, therefore, critical that it is accounted for in the hardware
verification, otherwise we do not know the actual risk reduction
capability of the SIF.
Even if the C
PT
values are taken from the Safety Manual and included
in the the verification, if the recommended PT is not fully adopted by
the end user in the PT there is the potential that the C
PT
could be even
lower.