Safety Decision Making - Drawing a Line in the Sand

Operational personnel in complex process plant 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 in place a set of operating limits. 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 a pre-defined operating envelope underestimates the direct contribution to safety from 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 are wrong, it is simply a reflection that not every possible state of a complex dynamic system 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.