IM 01E21A21-02EN
<2. Safety Instrumented Systems Installation>
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2.3 Definitions and Abbreviations
2.3.1 Definitions
● Safety
Definition
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
defined 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 fire and
explosion. The protection must be effective under all conditions of the nominal operation
and under single fault condition.
● Verification
Definition
Contents
Verification
The demonstration for each phase of the life-cycle that the (output) deliverables of the
phase meet the objectives and requirements specified by the inputs to the phase. The
verification 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 Specification. 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 definitions 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
Definition
Contents
FMEDA
Failure Mode, Effects and Diagnostic Analysis
SIF
Safety Instrumented Function
SIL
Safety Integrity Level
SIS
Safety Instrumented System
SLC
Safety Lifecycle