Inherently Safer Design: Lessons Learned about the Principle of Simplification

The American Institute of Chemical Engineers (AIChE), the Chemical Safety Board (CSB), and the Occupational Safety and Health Administration (OSHA) have all emphasized the importance of advancing inherently safer design concepts into chemical process plants. Incident investigations offer an important opportunity to identify, evaluate, and correct potential shortcomings in the design, construction, operation, and maintenance of a chemical process unit that has experienced a release.

This paper focuses on the inherently safer design principle of simplification. The case studies share the common theme of storing or handling liquids.  Each case study illustrates how a design flaw led to unintended flow, reverse flow, or overfilling of a vessel which ultimately led to a fire, explosion, or hazardous release. Based on the incident investigation experiences of the authors, the paper illustrates how application of the simplification principle could have prevented these incidents.