ISA TR84.00.02 PART 5

W/D S/D BY ISA TR84.00.02

ISA-TR84.00.02-2002 – Part 5 is informative and does not contain anymandatory requirements.ISA-TR84.00.02-2002 – Part 5 is intended to be used only with athorough understanding ofISA-TR84.00.02-2002 – Part 1 which defines the overall scope.

ISA-TR84.00.02-2002 – Part 5 provides:

a) guidance in PFD analysis of logic solvers;

NOTE The term “logic solver” will be used throughout Part 5 toindicate the SIS logic solver. Thelogic solver technology may be any E/E/PES.

b) a method to determine the PFD of logic solvers;

c) failure rates and failure modes of logic solvers;

d) the impact of diagnostics, diagnostic coverage, covert faults, testintervals, common cause,systematic failures, redundancy of logic solvers on the PFD of thelogic solver; and

e) a method for the verification of PFD of logic solvers.

The procedures and examples outlined in ISA-TR84.00.02-2002 – Part 5provide the engineer withMarkov modeling steps to be followed in determining a mathematicalvalue for the PFD for typicalconfigurations of SIS logic solvers designed according toANSI/ISA-84.01-1996.

Persons using ISA-TR84.00.02-2002 – Part 5 require a basic knowledgeof Markov Analysis.

See ISA-TR84.00.02-2002 – Part 1 (Introduction), Part 2 (SimplifiedEquations), Part 3 (Fault TreeAnalysis), and Part 4 (Markov Analysis) if it is necessary tomathematically evaluate the SIL ofthe safety instrumented function (SIF).

NOTE The method illustrated herein (i. e. Markov analysis) may also beused to determine the PFD ofother SIF components such as sensors and final elements. The logicsolver was selected toillustrate how Markov Analysis is applied to a complex SIF component.

Edition:

02

Published:

06/17/2002

Number of Pages:

106

File Size:

1 file , 920 KB