IM 01E21A21-02EN
<2. Safety Instrumented Systems Installation>
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2.3 Denitions and Abbreviations
2.3.1 Denitions
● Safety
Denition Contents
Safety Freedom from unacceptable risk of harm.
Functional Safety The ability of a system to carry out the actions necessary to achieve or to maintain a
dened safe state for the equipment/machinery/plant/apparatus under control of the
system.
Basic Safety The equipment must be designed and manufactured such that it protects against risk of
damage to persons by electrical shock and other hazards and against resulting re and
explosion. The protection must be eective under all conditions of the nominal operation
and under single fault condition.
● Verication
Denition Contents
Verication The demonstration for each phase of the life-cycle that the (output) deliverables of the
phase meet the objectives and requirements specied by the inputs to the phase. The
verication is usually executed by analysis and/or testing.
Validation The demonstration that the safety-related system(s) or the combination of safety-
related system(s) and external risk reduction facilities meet, in all respects, the Safety
Requirements Specication. The validation is usually executed by testing.
Safety Assessment The investigation to arrive at a judgment based on evidence of the safety achieved by
safety-related systems.
Further denitions of terms used for safety techniques and measures and the description of safety-related
systems are given in IEC 61508-4.
2.3.2 Abbreviations
Denition Contents
FMEDA Failure Mode, Eects and Diagnostic Analysis
SIF Safety Instrumented Function
SIL Safety Integrity Level
SIS Safety Instrumented System
SLC Safety Lifecycle