ISA TR84.00.02-1 : 2002

Foreword
Introduction
1 Scope
2 References
3 Definitions of terms and symbols
  3.1 Definition of terms
  3.2 Definition of symbols
4 Probability of failure on demand (PFD)
5 Modeling of SIF element failures
  5.1 Physical failures
  5.2 Hardware common cause failures
  5.3 Systematic failures
  5.4 Partitioning of SIF element failures
  5.5 Modeling of field devices
  5.6 Modeling of elements in PES arithmetic/logic
      solvers
  5.7 System modeling
  5.8 Failure rate data for commonly used field
      instrumentation
  5.9 Statistical data analysis methods
6 Comparison of system analysis techniques
Annex A (informative) - Methodology for quantifying the
                        effect of hardware-related common
                        cause failures in Safety Instrumented
                        Functions
Annex B (informative) - Fault simulation test procedure
Annex C (informative) - SIL quantification of SIS - Advisory
                        software packages
Annex D (informative) - Failure mode effect, hazard and
                        criticality analysis
Annex E (informative) - Common cause failures and systematic
                        failure checklist
Annex F - Index

ISA-TR84.00.02-2022, Safety Integrity Level (SIL) Verification of Safety Instrumented Functions, is a comprehensive technical report by the International Society of Automation (ISA) providing guidance on the verification of safety integrity levels (SIL) for safety instrumented functions (SIF) within safety instrumented systems (SIS) in process industries. It supports ANSI/ISA-61511-1:2018 by detailing methodologies to assess and verify the average probability of failure on demand (PFDavg), probability of failure per hour (PFH) and spurious trip* rates through quantitative techniques such as fault tree analysis and Markov modeling. ISA-TR84.00.02 covers classification and estimation of random and systematic failures, diagnostic coverage, common cause failures, voting architectures and asset integrity programs essential for maintaining SIS performance. It includes practical examples, equations and annexes addressing complex scenarios like multiple safeguards, operator-initiated functions, partial testing and integration with mechanical safeguards. The technical report emphasizes that SIL verification is performance-based, requiring careful understanding of assumptions, device selection, management systems and operational data to maintain safety lifecycle compliance and effectively reduce risk. *A spurious trip, also known as a safe failure or false trip, is an unintended shutdown of a safety instrumented system (SIS) that occurs when a safety function is triggered without a genuine process demand. This means the system incorrectly believes there's a problem and initiates a shutdown, even though the process is operating normally.