Acronyms - GE Masoneilan SVI II ESD Installation And Maintenance Manual

Fail Dangerous
Undetected
Fail Dangerous Detected
Fail Annunciation
Undetected
Fail Annunciation Detected Failure that does not cause a false trip or prevent the safety function
Fail No Effect
Low Demand Mode

Acronyms

The following acronyms are related to safety functions of the SVI II ESD and are used
throughout this document.
FMEDA
HFT
MOC
PFDavg
PST
SFF
SIF
SIL
SIS
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Failure that is dangerous and that is not being diagnosed by auto-
matic stroke testing.
Failure that is dangerous but is detected by automatic stroke testing.
Failure that does not cause a false trip or prevent the safety function
but does cause loss of an automatic diagnostic and is not detected
by another diagnostic.
but does cause loss of an automatic diagnostic or false diagnostic
indication.
Failure of a component that is part of the safety function but that has
no effect on the safety function.
Mode, where the frequency of demands for operation made on a
safety-related system is no greater than twice the proof test fre-
quency.
Failure Modes, Effects and Diagnostic Analysis
Hardware Fault Tolerance
Management of Change. These are specific procedures often done
when performing any work activities in compliance with government
regulatory authorities.
Average Probability of Failure on Demand
Partial Stroke Test, a test used to detect failure modes in the posi-
tioner, actuator, and valve assembly.
Safe Failure Fraction, the fraction of the overall failure rate of a
device that results in either a safe fault or an diagnosed unsafe fault.
Safety Instrumented Function, a set of equipment intended to reduce
the risk due to a specific hazard (a safety loop).
Safety Integrity Level, discrete level (one out of a possible four) for
specifying the safety integrity requirements of the safety functions to
be allocated to the E/E/PE safety-related systems where Safety
Integrity Level 4 has the highest level of safety integrity and Safety
Integrity Level 1 has the lowest.
Safety Instrumented System – Implementation of one or more Safety
Instrumented Functions. A SIS is composed of any combination of
sensor (s), logic solver (s), and final element (s).
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