Visual ergonomics in control room environments: A case study from a swedish paper mill

Abstract

This paper presents results from a case study at a Swedish paper mill. The study is part of a larger ongoing research project aiming to investigate visual ergonomics in control room environments. Visual conditions were measured and evaluated in five control rooms, and nine process operators answered questions about perceived workload and visual experience. The participating operators rated their mental workload as being the highest, but also mentioned a high physical load and time pressure. Six operators indicated that they had work-related eye problems and experienced pronounced eye fatigue, as well as eye discomfort, sore eyes and blurred vision. In one of the visited control rooms, where the operators indicated that they often experienced eye problems, the operators were clearly subjected to glare. Light was reflected within the field of view from a steel plate outside the control room windows. Compared to recommendations for office workplaces, the illuminance levels were low in all control rooms except one, causing contrast glare since computer screens generally had a higher luminance. Low contrasts were also identified in the computer screens between background and characters. In conclusion, the measured visual conditions could be related to an increased visual load, leading to visual discomfort. This may lead to pain in the neck, shoulders, and contribute towards an unnecessary high mental load. Recommendations are suggested of how lighting conditions van be improved.