Risk Based Design of Overpressure Protection Systems

Keywords: Process Safety Management (PSM), Process Hazard Analysis (PHA), Layer of Protection Analysis (LOPA), Safety Instrumented Systems (SIS), Inherently Safer Design (ISD).

"Honeywell International’s Performance Materials and Technologies group is building a new world-scale facility to make reduced global-warming refrigerants and blowing agents in China. The project applied risk based work processes to Safety Instrumented Systems (SIS) design and application, including a multi-step PHA and LOPA process that recommended several Safety Instrumented Functions to deal with overpressure scenarios that were identified. Other applicable Independent Protection Layers (IPLs) are included in the LOPA risk evaluation as well. Honeywell’s  Automation and Controls group is assisting with the design of these systems. Using real-world examples, this paper will illustrate how hazards can be identified and then managed using high reliability safeguards. It will also illustrate the importance of using “standard” loops by providing several practical examples, to simplify designs as well as proof-testing over the life of the plant.”