Issues in the Design of Annunciator Systems

A major source of qualitative information in nuclear power plant control rooms is provided by the annunciator system. In many control room operations the alarm system is the initiating stimulus for operator response. Annunciators are an especially critical source of information in an emergency. For this reason, sound annunciator design and layout are crucial to efficient and safe nuclear power plant operation. Over the past few years, several investigators have determined that annunciator systems fail to fulfill the intended purpose. Human factors engineering principles often have been ignored or violated. Much work is needed to optimize the man-machine interface of annunciator systems. This paper discusses the importance of human factors criteria for consistency, accuracy, readability, position, and priority in the design of annunciator systems. The areas of functional grouping and prioritization, standardization of window nomenclature and format, and color coding are reviewed and evaluated. Additional problem areas in the design of an annunciator system are identified.