(114b) “We Will Know We Have a Problem, and We Will Fix It!” – Overestimating Human Response As a Safeguard

Human response to an alarm is an incredibly common safeguard in many process hazard analysis (PHA) studies. Correct human response to abnormal conditions can be a powerful safeguard in preventing catastrophic process safety events, but human response also has several significant limitations to consider and overcome. It is incredibly tempting, in the relative calm of the PHA discussions or operating procedure reviews, to assign near-superhero qualities to operations personnel in how they respond to upset conditions and attempt to prevent upsets from escalating to loss of containment events. However, the reality of chemical process operations is almost always much messier and more complex. Failure to reflect honestly on the physical and mental limitations of the humans charged with making critical decision in process operations will result in a higher-than-expected risk of process safety events. This paper will evaluate some of the ways human response can be overestimated as a safeguard and illustrate them with real-world examples. Facing the limitations of human response in a given scenario can help both manufacturing leaders and process safety specialists identify ways to strengthen it. Factors to consider when relying on human response and ways to improve the effectiveness of human safeguards through both engineering design and human factors will also be discussed.