AC/DC: Alternating current/direct current
AIChE: American Institute of Chemical Engineers
ALARP: As low as reasonably practicable
ANSI: American National Standards Institute
AP: Application program
BPCS: Basic process control system
CCPS: Centre for Chemical Process Safety (AIChE)
DC: Diagnostic coverage
E/E/PE: Electrical/electronic/programmable electronic
EMC: Electro-magnetic compatibility
FAT: Factory acceptance test
FPL: Fixed program language
FSA: Functional safety assessment
FSMS: Functional safety management system
FTA: Fault tree analysis
FVL: Full variability language
HFT: Hardware fault tolerance
H&RA: Hazard & risk assessment
HMI: Human Machine Interface
IEC: International Electrotechnical Commission
ISA: International Society of Automation
ISO: International Organization for Standardization
LVL: Limited variability language
MooN: “M” out of “N” channel architecture
MPRT: Maximum permitted repair time
MRT: Mean repair time
MTTR: Mean time to restoration
NFPA: National Fire Protection Association (US)
NP: Non-programmable
OEM: Original Equipment Manufacturer
PE: Programmable electronics
PES: Programmable electronic system
PFD: Probability of dangerous failure on demand
PFDavg: Average probability of dangerous failure on demand
PFH: Probability (average frequency of dangerous failures) of failure per hour
pl: Plural
PLC: Programmable logic controller
SAT: Site acceptance test
SC: Systematic capability
SIF: Safety instrumented function
SIL: Safety integrity level
SIS: Safety instrumented system
SRS: Safety requirement specification