Abbreviations (acronyms) used in Functional Safety
Greek Letters
β: Beta factor for common cause failures (for DU failures)
βD: Beta factor for common cause failures (for DD failures)
λDD : Rate of Dangerous Detected failures (failures per hour)
λDU : Rate of Dangerous Undetected failures (failures per hour)
λSD : Rate of Safe Detected failures (failures per hour)
λSU : Rate of Safe Undetected failures (failures per hour)
From A to L
BPCS: Basic Process Control System (also DCS)
CC: Common Cause
CCF: Common Cause Failure
Cpt: Coverage of Proof Tests (also PTC)
DC: Diagnostic Coverage [λDD / (λDU + λDD)]
DCS: Distributed Control System (also BPCS)
DTT: De-energized To Trip
E/E/PE: Electrical, Electronics, and Programmable Electronic
ESD: Emergency Shut Down
ETT: Energized To Trip
EUC: Equipment Under Control
FAT: Factory Acceptance Tests
FC: Fail Close (valve close when power/air failure)
FE: Final Element (actuator subsystem)
F&G: Fire & Gas
FIT: Failures in Time (failures per billion hours; λ=FIT x 1E-9)
FMEA: Failure Mode and Effect Analysis
FMEDA: Failure Modes, Effects, and Diagnostic Analysis
FO: Fail Open (valve open when power/air failure)
FST/FVST: Full Valve Stroke Test
GUI: Graphic User Interface
HAZID: Hazard Identification study
HAZOP: Hazard and Operability study
HFT: Hardware Fault Tolerance
HIPPS: High Integrity Pressure Protection System
HMI: Human Machine Interface
HP: High Pressure
ICSS: Integrated Control & Safety System
IEC: International Electrotechnical Commission
IPL: Independent Protection Layer
IS: Intrinsically Safe
LT: Life Time of the SIF (also MT)
From M to Z
MDT: Mean Detection Time (MTTR=MDT+MRT)
MooN: M out of N (architecture)
MOV: Motorized Valve
MPRT: Maximum Permitted Repair Time
MRT: Mean Repair Time (MTTR=MDT+MRT)
MT: Mission Time of the SIF (also LT)
MTBF: Mean Time Between Failures
MTTF: Mean Time To Failure
MTTFS: Mean Time To Fail Spuriously
MTTR: Mean Time To Restore (MTTR=MDT+MRT)
NC: Normally Closed
NO: Normally Open
PFD: Probability of Failure on Demand
PFDavg : Average Probability of Failure on Demand
PFH: Probability of Dangerous Failure per Hour
PFS: Probability of Failing Safely
PHA: Process Hazard Analysis
PL: Performace Level (for machinery)
PLC: Programmable Logic Controller
PRV: Pressure Relief Valve
PST: Process Safety Time
PST/PVST: Partial Valve Stroke Test
PTC: Proof Test Coverage (also Cpt)
PTD: Proof Test Duration (hours with bypass activated)
RBD: Reliability Block Diagram
RO: Restriction Orifice
RRF: Risk Reduction Factor
SAT: Site Acceptance Tests
SFF: Safe Failure Fraction
SIF: Safety Instrumented Function
SIL: Safety Integrity Level
SIS: Safety Instrumented System
SOV: Solenoid Valve or Shut-off Valve
SRS: Safety Requirements Specification
STR: Spurious Trip Rate
TBD: To Be Defined
TI: Test Interval
Tags
Measures of:
B: Combustion, Flame
F: Flow
L: Level
P: Pressure
R: Radiation
S: Speed, Frequency
T: Temperature
V: Vibration
Z: Position
For equipment:
C: Compressor
P: Pump
R: Relay
S: Switch
T: Transmitter
XV: Valve
XY: Solenoid Valve
For setpoint:
H: High
HH: High High
L: Low
LL: Low Low
Examples:
PT-10: Pressure Transmitter
FSL-25: Flow Switch for Low Trip/Alarm
FSLL-26: Flow Switch for Low Low Trip/Alarm
ZSO-100: Proximity Switch for Open position
ZSC-100: Proximity Switch for Closed position
XV-100: Safety Valve
P-100A: Pump
VSHH-200: High High Vibration Switch
Related links:
Glossary of Terms: https://www.exida.com/Resources/Glossary/a