Operational personnel in complex process plants such as major hazard facilities are regularly called upon to make decisions that balance the production and safety requirements of their organisation. Hazardous facilities that operate under safety case-style regulatory regimes typically have a set of operating limits in place. These limits normally cover both restrictions on process parameters and required minimum safety equipment availability, apparently removing the need for in-the-moment judgements.Focussing solely on compliance with pre-defined operating limits underestimates the direct contribution to safety made by the operating team based on their professional judgement. In practice there are many possible system conditions that do not contravene the defined operating limits and yet are not safe. This does not mean that the procedure writers’ procedure is incorrect– it is simply a reflection that in a complex dynamic system not every possible state can be identified in advance. Research has identified a line in the sand approach taken by experienced operating crews when abnormal situations arise. This approach could form the basis of a process rule (similar to job safety analysis or permit to work) to assist operational crews in making better decisions when such situations arise.
Hayes, Jan, 2010, WP 74 - Safety decision making: Drawing a line in the sand, National Research Centre for OHS Regulation, Canberra