Consulting and Engineering Services

Doc No. 0418D10SD01 – Rev.01                            


1.    Functional Safety Abbreviations


%WC                          Percentage Weight Contribution on the Total PFDavg value

1oo1                            One(1) out of One(1) safety channel architecture.

1oo1D                         One(1) out of One(1) safety channel architecture with Diagnostics.

1oo2                            One(1) out of Two(2) safety channel architecture.

1oo2D                         One(1) out of Two(2) safety channel architecture with included additional Diagnostics among channels to verify safety channels interoperability.

1oo3                            One(1) out of Three(3) safety channel architecture.

2oo2                            Two(2) out of Two(2) safety channel architecture.

2oo3                            Two(2) out of Three(3) safety architecture.

2oo3D                         Two(2) out of Three(3) safety channel architecture with included additional Diagnostics among channels to verify safety channels interoperability.

3oo3                            Three(3) out of Three(3) safety channel architecture.

Beta                            (β) Common Cause Failure factor for Dangerous UnDetected failures

BetaD                         (βD) Common Cause Failure factor for Dangerous detected failures

BPCS                         Basic Process Control System

CCF                            Common Cause Failure

CMF                           Common Mode Failure

CPU                            Central Processing Unit

CRV                            Cartridge Valve

DC                              (or CDD) Diagnostic Coverage factor for Dangerous failures

DCS                            Distributed Control System. See "PCS".

E/E/PE                        Electrical, Electronic, Programmable Electronic safety-related system

ESDV                         Emergency Shutdown Valve

ESV                            Emergency Shutdown Valve

Et                                Proof Test Effectiveness

EUC                            Equipment Under Control

FE                               Final safety Element

FIT                              Failure In Time (1x10-9 per hour).

FMEA                         Failure Modes and Effects Analysis

FMECA                      Failure Modes, Effects and Criticality Analysis

FMEDA                      Failure Modes, Effects and Diagnostic Analysis

FSE                            Final Safety Element

FSM                            Functional Safety Management

FSP                            Functional Safety Plan

FVST                          Full Valve Stroke Test

GUI                             Graphic User Interface

HART                         Highway Addressable Remote Transducer protocol

HAZID                        Hazard Identification Study

HAZOP                       Hazard and Operability Study

HFT                            Hardware Fault Tolerance

HIPPS                        High Integrity Pression Protection System

HIPS                           High Integrity Protection System

HMI                             Human Machine Interface

HPA                            Hazard Process Analysis

IPF                              Instrumented Protective Function

IPS                              Instrumented Protective System

IS                                Intrinsically Safe

K, or Kfactor               Efficiency of inter-channel comparison / automatic switch mechanism in the 1oo2D Safety Architecture. Fraction of the success of the autotest circuit in the 1oo2D system

LdDD, or lDD              Dangerous detected failure rate

LdDU, or lDU              Dangerous UnDetected failure rate

LdSD, or lSD               Safe detected failure rate

LdSU, or lSU               Safe UnDetected failure rate

MART                         Maximum Allowed Response Time (see “SRT”)

MRT                           Mean Restoration Time

MSLS                         Main Safety Loop Series

MSSDL                       Maximum SIL Safety Design Limit

MSSTRDL                  Maximum “Spurious Trip Rate” (STR) Safety Design Limit

MTBF                         Mean Time Between Failures

MTTF                          Mean Time To Failure

MTTFD                        Mean Time To Dangerous Failure

MTTFs                        Mean Time To Failure Spuriously

MTTFspuriously         Mean Time To Failure Spuriously

MTTR                          Mean Time to Restoration

N/A                             Not Applicable

NA                              Not Applicable

NDE                            Normally De-Energized

NE                               Normally Energized

NIS                             Non-Intrinsically Safe

OOS                           Out Of Service

PCS                            Process Control System. See "DCS".

PE                               Programmable Electronic

PFDavg                      Average Probability of Dangerous Failure on Demand

PHA                            Process Hazard Analysis

PRV                            Pressure Relief Valve

PST                            Process Safety Time

PTC                            Proof Test Coverage

PVST                          Partial Valve Stroke Test

QSV                            Quick Shutdown Valve

RBD                            Reliability Block Diagram

RO                              Restriction Orifice

RPN                            Risk Priority Number

RRF                            Risk Reduction Factor

SCA                            Safety Channel Architecture

SFF                             Safe Failure Fraction

SIF                              Safety Instrumented Function

SIL                              Safety Integrity Level

SIS                              Safety Instrumented System

SLf                              Service Life

SmPosT                     Smart Position Transmitter

SOV                            Solenoid Valve

SPST                          Single Pole Single Trough

SRS                            Safety Requirements Specification

SRT                            Safety Response Time

STL                             Spurious Trip Level

STR                            Spurious Trip Rate

STRavg                      Average Spurious Trip Rate

TBDbC                       To be defined by calculation case

TD                               Proof test Duration

TI                                Proof Test Period

XooN                          X-out-of-N voting logic, or “Safety Channel Architecture” (SCA) of N inputs/Channels where “X” inputs/Channels decide the whole SCA state.

XooN(D)                     Same SCA as "XooN", but additional diagnostic are included to verify safety channels interoperability.