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Copyright © 2014 by Cenbee Bullock PFS Consulting Ltd
PFS
Specialising
In Functional Safety
Minimising Systematic Failures in SIS Design
Examples – Human errors during installation & Testing
Mis-calibration
of the instrument such as level/pressure transmitter
Forget to re-open and lock the block valves
under a relief valve after
maintenance and before the relief valve is returned to normal
service
Leaving the transmitter/sensor root valve closed
causing an unsafe
failure
Leaving the entire SIF in BYPASS
after maintenance or after some
other human intervention (such as an unintended error or as
necessity during the start-up)