Upset/Off-Normal Workload Analysis

The requirements for responding to a unit upset establishes the minimum staffing levels for process units. Different methods are used to determine the requirements for outside operators and board operators.

Outside operator requirements to handle an emergency are assessed through procedural walk-throughs. A worst case upset is chosen and the operators are asked to "walk through" their actions. In the course of the walk-through, the operators are queried as to difficult tasks, potential problems due to equipment malfunction or variations in the upset. The operators’ actions are observed to determine if equipment is accessible or information is available to make decisions and/or take action. The walk-though results are then formatted in a flowchart style for easier viewing.

After being put into the flowchart format, the tasks are rated along two dimensions: (1) Risk and (2) Effort. Risk is associated with the consequence of not performing the task, and effort refers to the physical effort experienced by the operators while performing the task. This analysis of the tasks allows Beville to identify both bottleneck tasks and upset load/utilization.

Determining the upset requirements for board operators involves "talking through" a worst-case upset and evaluating the DCS configuration and alarm system structure, along with other variables. Frequently the problems in upset response originate with poor DCS configuration, which limits the board operator's ability to respond effectively to an upset situation. If it is determined that the majority of problems originate at the board, it is necessary to ascertain the causes of the problems and potentially perform an alarm and display system analysis to go hand in hand with the upset response management.

If upset staffing requirements are greater than steady state staffing for a unit, two sets of options are developed. One option entails increasing the steady state workload to improve personnel utilization. The other option involves automating upset tasks to reduce the workload needed to handle an upset.