Understanding ISA-84 and Functional Safety in the Process Sector

This is an excerpt from InTech magazine and was written by William Johnson, Richard R. Dunn, and Victor J. Maggioli.

Functional safety within the process sector has always been a priority. As the process sector moved into the computer age, new issues arose as manufacturing plants converted to computer control to replace electrical, pneumatic, and electronic controls. The process sector developed a variety of tools to address these problems, but safety performance did not always meet expectations. The need for improved understanding and harmonization of risk reduction approaches became evident with the occurrence of such major catastrophes as Seveso (Italy), Bhopal (India), Flixborough (U.K.), and Chernobyl (Ukraine). In response, OSHA developed and published OSHA 29 CFR, 1910.119-1992 (Final Rule: 24 February 1992), Process Safety Management of Highly Hazardous Chemicals, Explosives, and Blasting Agents; and the U.S. Environmental Protection Agency published EPA 40 CFR Part 68, Accidental Release Prevention Requirements: Risk Management Programs under the Clean Air Act (U.S. only). These regulations helped define areas that must be addressed in order to achieve a mandated level of functional safety performance in industry.

ISA-84: Important functional safety standard for automation in the computer age

The International Society of Automation (ISA, formerly Instrument Society of America) recognized the need for an improved approach in handling process sector functional safety issues. As a result, ISA established Standards Project 84 (SP84, now called ISA84) to address this issue.

ISA84 scope

  1. To define terminology that is particular to Electrical/Electronic/Programmable Electronic Systems (E/E/PES) and high reliability.
  2. Establish criteria for, and means of assessing, reliability and availability in practical applications.
  3. Provide general specification guidelines that facilitate understanding.
  4. Provide guidelines for process safety applications requiring high reliability.
  5. Develop guidelines for specific hardware/software configurations that can meet varying levels of reliability/availability.
  6. This work does not apply to nuclear power safety-related systems.

ISA84 purpose

To develop standards and technical reports for use in applying Electrical/Electronic/Programmable Electronic Systems (E/E/PES) for use in process safety applications.

The full article outlines additional key elements of the ISA-84 committee on process sector functional safety. It also provides a preview of the forthcoming 2nd edition of ANSI/ISA-84.00.01 (IEC 61511 Mod).

Click here to read the full article at InTech magazine.

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