Evaluation of Work Station Design Factors in VDT Operations

Abstract

An onsite evaluation was conducted at five establishments using VDTs to examine VDT workstation designs and to compare these designs to recommendations obtained from the literature. Measurements were made of such critical design factors as keyboard height, screen height, workstation illumination, and glare. Illumination levels were generally in the 500 to 700 lx range, and questionnaire data confirmed that these levels were acceptable to most employees. A number of design problems were found in the VDT workstations, including excessive keyboard heights and screen positioning which would require excessive inclination of the head and neck for screen viewing. A majority of the operators surveyed found a number of factors to be bothersome, including screen readability, reflected glare, screen brightness, and flicker. A number of the dissatisfaction parameters were found to be related to levels of somatic (health) complaints.

Worksheets for Computing Recommended Notebook Computer and Workstation Adjustments

“…Based on four workstation design factors, namely, keyboard height, screen height, workstation illumination, and glare, Stammerjohn, Smith, and Cohen recommended that an acceptable range of the viewing distance for VDT operation be 45-70 cm [27]. Saito, Miyao, Konto, et al conducted an evaluation of working conditions and musculoskeletal posture on 10 subjects by comparing viewing distance, viewing angle, head angle, neck angle, and electromyography (EMG) on neck, back, and shoulder muscles [28].…”

Human factors evaluation of remote afterloading brachytherapy: Human error and critical tasks in remote afterloading brachytherapy and approaches for improved system performance. Volume 1

“…Appendix B (Bullinger, Kern, and Muntzinger, 1987;Grandjean, 1987;Stammerjohn, Smith, and Cohen, 1981). When the system does not provide this feedback information, users find it difficult to make correct and timely responses, especially when anomalous conditions arise.…”

Human factors issues in VDT use: Environmental and workstation design considerations

“…In addition, almost two thirds of the VDT operators complained that the air was too dry, even though the relative humidity in their workplace was between 30 and 40 percent. In the NIOSH San Francisco study, 13 …”

“…In many of the field studies, 12 these contrast ratios were found to be much less than optimal (7:1 to 10:1 is considered acceptable) and, in some cases, were less than adequate (3:1 is considered adequate). 13, 15 Grandjean 16 demonstrated that the quality of the screen characters can influence the level of health complaints with poorer quality images producing more visual complaints. Gould 17 indicated that blurred and/or flickering characters can be a contributing factor in the ability to read a video display.…”