NO GOOD DEED GOES UNPUNISHED - CASE-STUDIES OF INCIDENTS AND POTENTIAL INCIDENTS CAUSED BY PROTECTIVE SYSTEMS

In the course of chemical process and plant design, engineers identify potential hazardous incidents. These potential incidents may be ident ified through special hazard analysis reviews and procedures, or by th e design team in the course of design activities. To manage and contro l those hazards, the team will modify the initial design often by addi ng on additional protective devices and systems-alarms, interlocks or active protective systems. However, any change in a system, even a cha nge intended to prevent or mitigate a potential hazardous incident, al so has the potential to introduce new hazards or new mechanisms by whi ch existing hazards can result in an incident. A number of case studie s illustrating this point are reviewed. The examples illustrate the im portance of a management of change program, which must consider all ch anges including the addition of safety devices and systems, and which must thoroughly consider all potential effects on the system.