13.1 Introduction

Making changes to processes, control systems, safety systems, equipment, and procedures are inevitable. Modifications are required for a variety of reasons, including changes in technology, quality requirements, equipment malfunctions, or safety.

OSHA 29 CFR 1910.119 ("Process Safety Management of Highly Hazardous Chemicals") requires employers to "establish and implement written procedures to manage changes (except replacements in kind ) to process chemicals, technology, equipment, and procedures; and, changes to facilities that affect a covered process." [Ref. ^[1]]

Subclause 5.2.6.2.2 of ANSI/ISA-84.00.01 2004 states that "Management of modification procedures shall be in place to initiate, document, review, implement and approve changes to the safety instrumented system other than replacement in kind (i.e., like for like)."

This chapter focuses on management of change (MOC) as related to safety systems with specific reference to the OSHA and ANSI/ISA-84.00.01 2004 requirements. The MOC procedures are required to ensure that all changes are made in a safe, consistent, and well-documented manner.

13.2 The Need for Managing Changes

Changes made to a process, no matter how minor, may have severe safety implications. Take one major process accident the Flixborough explosion in England as an example.

In June 1974, there was a massive explosion at the Nypro factory in Flixborough that fundamentally changed the manner in which safety is managed by all industries.

The Nypro plant produced an intermediate used to make nylon.