Yokogawa RAGN - Manual (Page 44)

A1-4
IM 01R01B10-00E-E 2nd edition: November 01, 2011-00 All Rights Reserved. Copyright © 2011, Rota Yokogawa
A1.3 Definitions and Abbreviations
A1.3.1 Definitions
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 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.
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
A1.4 Assessment results
A1.4.1 Safety related parameters
The following results have been obtained from the assessment report Report No.: ROTA YOKOGAWA 11/04-
36 R004 Version V1, Revision R1; November 2011 issued by exida.
Average PFD values have been calculated assuming a Diagnostic Coverage (DC) of 99%, a mission time of
10 years and a Mean Time to Restoration of 24 hours.