ISA 84.00.01 P3

W/D REPLACED BY ISA 61511-3

This part provides information on

– the underlying concepts of risk, the relationship of risk tosafety integrity, see Clause 3;

– the determination of tolerable risk, see Annex A;

– a number of different methods that enable the safety integritylevels for the safety instrumented functions to be determined, seeAnnexes B, C, D, E, and F.

In particular, this part

a) applies when functional safety is achieved using one or moresafety instrumented functions for the protection of eitherpersonnel, the general public, or the environment;

b) may be applied in non-safety applications such as assetprotection;

c) illustrates typical hazard and risk assessment methods thatmay be carried out to define the safety functional requirements andsafety integrity levels of each safety instrumented function;

d) illustrates techniques/measures available for determining therequired safety integrity levels;

e) provides a framework for establishing safety integrity levelsbut does not specify the safety integrity levels required forspecific applications;

f) does not give examples of determining the requirements forother methods of risk reduction.

Annexes B, C, D, E, and F illustrate quantitative andqualitative approaches and have been simplified in order toillustrate the underlying principles. These annexes have beenincluded to illustrate the general principles of a number ofmethods but do not provide a definitive account.

NOTE Those intending to apply the methods indicated in theseannexes should consult the source material referenced in eachannex.

Figure 1 shows the overall framework forANSI/ISA-84.00.01-2004 Part 1 (IEC 61511-1 Mod),ANSI/ISA-84.00.01-2004 Part 2 (IEC 61511-2 Mod), andANSI/ISA-84.00.01-2004 Part 3 (IEC 61511-3 Mod), andindicates the role that this standard plays in the achievement offunctional safety for safety instrumented systems.

Figure 2 gives an overview of risk reduction methods.

For existing SIS designed and constructed in accordance withcodes, standards, or practices prior to the issue of this standard(e.g., ANSI/ISA-84.01-1996), the owner/operator shall determinethat the equipment is designed, maintained, inspected, tested, andoperating in a safe manner.

Edition:

04

Published:

09/02/2004

ANSI:

ANSI Approved

Number of Pages:

70

File Size:

1 file , 1.5 MB