Weak signals and human factors engineering
Lack of adequate attention to the principles of human factors engineering in design can make it more difficult for operators to detect or understand potentially critical information about the state of equipment, to understand how a process is behaving, or to be able to respond in an effective and timely manner. That is, failing to pay adequate attention to the human interface with technology can turn signals that otherwise could be strong into weak ones. This can apply to many areas of the design or layout of a facility and the human interfaces to equipment. It is, perhaps, especially true of the design of the on-screen graphics and interaction techniques embedded in human-computer interfaces.
Even if no additional HFE effort or analysis was conducted, simply ensuring compliance with the existing technical HFE design standards that are already widely adopted by capital projects across the industry—and especially standards and best practices for control room and human machine interface design—will lead to improvement in the ability of control room operators to detect and understand the significance of weak signals of danger that relate to the state of the operation or equipment. Many weak signals can be made stronger (or avoid being made weak by poor design) by improved application of the principles of HFE in design and the hard truths of human performance set out in Chapter 6.
Of course, improved application of HFE in design will not, of itself, improve the willingness of people to actually intervene if they do detect signals of potential danger. That depends on many organizational, operational and cultural factors well beyond the scope of HFE. Actions taken at an organizational level can directly affect the psychological processes that determine how people make decisions in the presence of uncertainty.
The impact of HFE on SA and TSD
There are many ways in which failing to properly implement human factors principles in design or operations management can make it more difficult for operators to detect early signs of trouble and, if they do detect trouble, to be motivated to action. Here are some examples that illustrate how the effective implementation of HFE in design can improve SA and make d′ bigger, making it easier for operators to identify signs of trouble early:
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Working environments that provide good access, sightlines and lighting in all areas that need to be regularly monitored and inspected; equipment that is properly and consistently labeled and with clear status indicators, so that it is easy to identify and operators can readily determine what state it is in; equipment layouts that don’t encourage operators to find easier ways of working because the expected ways are unnecessarily physically demanding, time-consuming or awkward.
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Control rooms that minimize distractions and ensure operators can view and access all the information they need efficiently; that ensure they are not distracted by discomfort; and that they can communicate clearly with people they need to both inside and outside the control room.
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Operator workstations and Human-Machine Interfaces that allow operators to maintain high levels of SA across the total span of their control; that make it easy to detect and identify trends or important changes in a systems performance; that allow operators to efficiently allocate attention to high-priority information, to see how parameters are changing over time, and to quickly access all of the information needed to perform a task. And in particular, displays that are designed to be cognitively compatible with the way the human brain processes information, thinks and reasons against goals so that the state of a complex system can be seen directly rather than requiring the operator to combine mentally information from many sources.
Table 8.1 illustrates how human factors issues that are determined either during the design of capital projects or by operational management can influence the three levels of SA, as well as both d′ (making signals easier to detect), and β (changing individuals criteria for taking action if they do detect a signal).