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Slide 8
InstMC FS2016 V1.3
Nicol Instrument Engineering Limited
Clarifies limits on
Frequency claimed for BPCS as an initiating
source:
–
BPCS
includes all of the devices
necessary to ensure that
the process operates in the desired manner, and may
implement various functions such as
process control
functions
,
monitoring
, and
alarms
.
–
Average frequency
of dangerous failures of a BPCS as
initiating source shall not be <10-5 per hour.
A BPCS protection layer (PL) risk reduction
at ≤ 10.
–
Where claimed a risk reduction > 10 the BPCS shall be
designed and managed to the requirements in IEC 61511.