ISA TR84.00.04 PART 1

Purpose

ANSI/ISA-84.01-1996, Application of Safety Instrumented Systems for the Process Industries, was replaced in 2004 by ANSI/ISA-84.00.01-2004 Parts 1-3 (IEC 61511 Modified), Functional Safety: Safety Instrumented Systems for the Process Industry Sector. The three-part series is the United States adoption of the international standards, IEC 61511 Parts 1-3, and includes one additional clause, a "grandfather clause" covering existing safety instrumented systems (see ANSI/ISA-84.00.01-2004 Part 1 Clause 1.0 y).

This Part 1 technical report provides guidance related to the transition of programs developed for the 1996 standard to one compliant with the intent of the 2004 standards. This Part 1 technical report also includes 16 informative annexes providing guidance from the ISA-SP84 committee on a wide range of topics related to the new standards. A companion technical report, ISA-TR84.00.04-2005 Part 2, provides an example illustrating some of the lifecycle steps in ANSI/ISA-84.00.01-2004.

This Part 1 technical report contains four main clauses. Clause 1 is the purpose. Clause 2 explains the origins of ANSI/ISA-84.00.01-2004 and discusses its relationship to other regulations, standards, and practices. Clause 3 and Annex A specifically address the grandfather clause and provide guidance on the evaluation of existing safety instrumented systems. Clause 4 assists the owner/operator in the transition from ANSI/ISA-84.01-1996 to ANSI/ISA-84.00.01-2004.

NOTE: Throughout this technical report, the term "ISA-84.01-2004" is used to refer to ANSI/ISA-84.00.01-2004 Parts 1-3 (IEC 61511 Modified). The term "ISA-84.01-1996" is used to refer to ANSI/ISA-84.01-1996.

See Annex R of this technical report for a list of references for all documents cited herein.