ISA 84.00.01 P3

Abstract

This part provides information on <br>The underlying concepts of risk, the relationship of risk to safety integrity, see Clause 3; <br>The determination of tolerable risk, see Annex A; <br>- a number of different methods that enable the safety integrity levels for the safety instrumented functions to be determined, see Annexes B, C, D, E, and F. <br>In particular, this part <br>a) applies when functional safety is achieved using one or more safety instrumented functions for the protection of either personnel, the general public, or the environment; <br>b) may be applied in non-safety applications such as asset protection; <br>c) illustrates typical hazard and risk assessment methods that may be carried out to define the safety functional requirements and safety integrity levels of each safety instrumented function; <br>d) illustrates techniques/measures available for determining the required safety integrity levels; <br>e) provides a framework for establishing safety integrity levels but does not specify the safety integrity levels required for specific applications; <br>f) does not give examples of determining the requirements for other methods of risk reduction. <br>Annexes B, C, D, E, and F illustrate quantitative and qualitative approaches and have been simplified in order to illustrate the underlying principles. These annexes have been included to illustrate the general principles of a number of methods but do not provide a definitive account. <br>NOTE Those intending to apply the methods indicated in these annexes should consult the source material referenced in each annex. <br>Figure 1 shows the overall framework for <u>ANSI/ISA-84.00.01-2004 Part 1 (IEC 61511-1 Mod)</u>, <u>ANSI/ISA-84.00.01-2004 Part 2 (IEC 61511-2 Mod)</u>, and <u>ANSI/ISA-84.00.01-2004 Part 3 (IEC 61511-3 Mod)</u>, and indicates the role that this standard plays in the achievement of functional safety for safety instrumented systems. <br>Figure 2 gives an overview of risk reduction methods. <br><u>For existing SIS designed and constructed in accordance with codes, standards, or practices prior to the issue of this standard (e.g., ANSI/ISA-84.01-1996), the owner/operator shall determine that the equipment is designed, maintained, inspected, tested, and operating in a safe manner</u>.