User guide

<Appendix 1. Safety Instrumented Systems Installation>
A1-3
IM 01C25T03-01E
A1.3 Denitions and
Abbreviations
A1.3.1 Denitions
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 dened
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 effective
under all conditions of the nominal operation
and under single fault condition
Verication
The demonstration for each phase of the life-
cycle that the (output) deliverables of the phase
meet the objectives and requirements specied
by the inputs to the phase. The verication 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
Specication. 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 denitions of terms used for safety
techniques and measures and the description of
safety related systems are given in IEC 61508-4.
A1.3.2 Abbreviations
FMEDA
Failure Mode, Effects and Diagnostic Analysis
SIF
Safety Instrumented Function
SIL
Safety Integrity Level
SIS
Safety Instrumented System
SLC
Safety Lifecycle