ISA 84.00.01 P1

W/D REPLACED BY ISA 61511-1

This International Standard gives requirements for thespecification, design, installation, operation and maintenance of asafety instrumented system, so that it can be confidently entrustedto place and/or maintain the process in a safe state. This standardhas been developed as a process sector implementation of IEC61508.

In particular, this standard

a) specifies the requirements for achieving functional safetybut does not specify who is responsible for implementing therequirements (for example, designers, suppliers, owner/operatingcompany, contractor); this responsibility will be assigned todifferent parties according to safety planning and nationalregulations;

b) applies when equipment that meets the requirements of IEC61508, or of 11.5 of ANSI/ISA-84.00.01-2004 Part 1 (IEC 61511-1Mod), is integrated into an overall system that is to be usedfor a process sector application but does not apply tomanufacturers wishing to claim that devices are suitable for use insafety instrumented systems for the process sector (see IEC 61508-2and IEC 61508-3);

c) defines the relationship between ANSI/ISA-84.00.01-2004(IEC 61511Mod), and IEC 61508 (Figures 2 and 3);

d) applies when application software is developed for systemshaving limited variability or fixed programmes but does not applyto manufacturers, safety instrumented systems designers,integrators and users that develop embedded software (systemsoftware) or use full variability languages (see IEC 61508-3);

e) applies to a wide variety of industries within the processsector including chemicals, oil refining, oil and gas production,pulp and paper, non-nuclear power generation;

NOTE Within the process sector some applications, (for example,off-shore), may have additional requirements that have to besatisfied.

f) outlines the relationship between safety instrumentedfunctions and other functions (Figure 4);

g) results in the identification of the functional requirementsand safety integrity requirements for the safety instrumentedfunction(s) taking into account the risk reduction achieved byother means;

h) specifies requirements for system architecture and hardwareconfiguration, application software, and system integration;

i) specifies requirements for application software for users andintegrators of safety instrumented systems (clause 12). Inparticular, requirements for the following are specified:

– safety life-cycle phases and activities that are to be appliedduring the design and development of the application software (thesoftware safety life-cycle model). These requirements include theapplication of measures and techniques, which are intended to avoidfaults in the software and to control failures which may occur;

– information relating to the software safety validation to bepassed to the organization carrying out the SIS integration;

– preparation of information and procedures concerning softwareneeded by the user for the operation and maintenance of theSIS;

– procedures and specifications to be met by the organizationcarrying out modifications to safety software;

j) applies when functional safety is achieved using one or moresafety instrumented functions for the protection of personnel,protection of the general public or protection of theenvironment;

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

l) defines requirements for implementing safety instrumentedfunctions as a part of the overall arrangements for achievingfunctional safety;

m) uses a safety life cycle (Figure 8) and defines a list ofactivities which are necessary to determine the functionalrequirements and the safety integrity requirements for the safetyinstrumented systems;

n) requires that a hazard and risk assessment is to be carriedout to define the safety functional requirements and safetyintegrity levels of each safety instrumented function;

NOTE See Figure 9 for an overview of risk reduction methods.

o) establishes numerical targets for average probability offailure on demand and frequency of dangerous failures per hour forthe safety integrity levels;

p) specifies minimum requirements for hardware faulttolerance;

q) specifies techniques/measures required for achieving thespecified integrity levels;

r) defines a maximum level of performance (SIL 4) which can beachieved for a safety instrumented function implemented accordingto this standard;

s) defines a minimum level of performance (SIL 1) below whichthis standard does not apply;

t) provides a framework for establishing safety integrity levelsbut does not specify the safety integrity levels required forspecific applications (which should be established based onknowledge of the particular application);

u) specifies requirements for all parts of the safetyinstrumented system from sensor to final element(s);

v) defines the information that is needed during the safety lifecycle;

w) requires that the design of a safety instrumented functiontakes into account human factors;

x) does not place any direct requirements on the individualoperator or maintenance person.

y) For existing SIS designed and constructed in accordancewith codes, standards, or practices prior to the issue of thisstandard (e.g., ANSI/ISA-84.01-1996), the owner/operator shalldetermine that the equipment is designed, maintained, inspected,tested, and operating in a safe manner.

Edition:

04

Published:

09/02/2004

ANSI:

ANSI Approved

Number of Pages:

104

File Size:

1 file , 720 KB