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Most major oil and chemical companies have seen the problems associated with operators fighting to save a unit from having to shutdown. Prolonged periods of high alarm actuation rates, constantly changing/shifting conditions, and rapid decisions have resulted in the shutdowns that operators were attempting to prevent. Often the shutdowns come with considerable costs to equipment and the environment. Many companies have taken the approach that rather than fighting the unit, the plants should be “parked,” taken to a safe stable condition until additional personnel are available to reduce the workload. Recent research indicates that this might be a prudent approach.

We all “know” that becoming mentally tired will reduce our ability to perform mental tasks; but how will the reduced ability manifest itself? A study by Dimitri van der Linden, Michael Frese and Sabine Sonnentag gives some insight into what happens when we become mentally fatigued. Dealing with non-routine situations often requires exploration activities to determine the best method for problem resolution.

In this study, exploration strategies were investigated for both experienced and inexperienced subjects (“The Impact of Mental Fatigue on Exploration in a Complex Computer Task: Rigidity and Loss of Systematic Strategies”, Human Factors, V45, No. 3, 2003, p 483-494). With fatigue, exploration strategies became less systematic, more trial-and-error, and more prone to mistakes regardless of experience level. However, the less experienced subjects also showed signs of increased rigidity, continuing to repeat “dead-end” paths or strategies. Knowing that operators dealing with an upset are certainly facing fatigue and therefore likely to become more rigid in their problem solving strategies, parking the unit is probably the safest option.

For further information, visit the links below.

| Workload/Staffing Analysis Overview | Steady State Workload Staffing Analysis | Steady State Job Samples | Upset Response Staffing Analysis | Overtime Calculator -Excel download |


Article Published By
Console Operator Staffing Workload And Automation - ISA Automation Week 2012
How Good is Your Operator's Mental Model? Mynah
Modularizing Emergency Procedures for Increased Ease of Use and Updating
Operator Performance Takes Center Stage Chemical Processing
Operator Training Gains Ground Chemical Processing
Operators Get More Help Chemical Processing
Simple, Strong and Easy-to-Use Control Global
Teach Operators to Make the Right Decisions Under Fire
The Keys to Operator Performance


This year's Fall meeting for the Center for Operator Performance will be October 24-26 in Corpus Christi. For more information, please contact Lisa Via. Guests are always welcome!


Our summer newsletter is now available. Click here!

Take our short survey on operator span of control. Click here (new window)

David Strobhar's book, "Human Factors in Process Plant Operation," is now available in both hardcover and Kindle e-book.

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