Computer workstation

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Unusual computer workstation

A screen workstation is a workstation that is located in a work room and is equipped with a screen device and other work equipment. ( Section 2, Paragraph 5 of the Workplace Ordinance )

General

Understood as an IT term , it is a combination of devices with which the “man-machine interface” is implemented and consists of a screen , input devices such as keyboard and pointing device and the software that controls these devices . In the extended context of work physiology and organization , other work equipment such as office chairs , work tables , other optional storage options and other devices such as B. the telephone to the VDU workstation.

Computer workstations are available in all offices and areas of administration .

Legislation

Employees who typically use as a significant part of their normal work, a visual display unit are in the European Union by the EC directive 90/270 / EEC of 29 May 1990 on the minimum requirements concerning safety and health at work with display screen equipment protected . Several EC directives have been implemented in Germany, including EC Directive 90/270 / EEC. Based on the authorization in Section 19 of the Occupational Safety and Health Act , the Federal Government issued the VDU Ordinance, which was later incorporated into the Workplace Ordinance.

Technical development

The rapid development in the field of information technology is particularly evident in computer workstations: until the introduction of personal computers (PC), only special devices called 'terminals' could be used as computer workstations . Then the PCs took over their function with the help of emulation software . Application software running on decentralized workstation computers can communicate with users directly via the interfaces in the computer operating system . Internet applications use web browsers to handle the user interface.

Optical-visual factors

When designing the computer workstation ergonomically , relevant optical and visual aspects should be taken into account. Various performance functions of the eyes play a role, such as a. the adaptation, accommodation, convergence, fixation, visual acuity, depth and time of perception.

For good vision without discomfort when working with a screen, individually optimized glasses may be required, especially for people with presbyopia. The screen can be ergonomically positioned relative to the eye according to the glasses and the individual visual characteristics.

In the case of a negative display (light characters on a dark background), the eyes are subject to time-consuming and stressful adaptation processes when switching between screen and printed information. Therefore, the positive representation (dark characters on a light background) is to be preferred.

Bright VDU workstations (apart from dark rooms) are cheaper in terms of glare, as reflections or sources of interference light are less reflected on a light background . A lack of sharpness in the lateral field of vision leads to headaches as well as watery and burning eyes. The frame rate should be greater than the flicker blend frequency (~ 50 Hz).

The term Rigid views ( English Office Eye Syndrome ) is understood the concentrated fixing the screen display and content in computer work. By fixing the screen, the eye “forgets” to blink (the blink is unconsciously suppressed). The regular blinking of the eye is essential for the development of the tear film, because with every blink of the eye the lipid layer protecting the tear film is reapplied and stabilized over the tear film. The lipid layer prevents evaporation or the tear film from running off the eye and thus prevents the development of dry eyes ( keratoconjunctivitis sicca ).

Device setting

Matt surfaces are advantageous with regard to reflective glare. Lateral daylight in the room serves to avoid glare and contrast reduction. For color screens with a maximum of five foreground colors , spectral colors such as red and blue that are in the border area should be avoided, since the eye is least sensitive here and these colors cannot be seen clearly at the same time, so that accommodation is also required (accommodation differences due to chromatic aberration ) .

Room lighting and distance

An absolute value for good lighting cannot be given. When designing good lighting conditions, the following points should be taken into account:

The illuminance (illuminance E = luminous flux / area) is of great importance for assessing the lighting. The more difficult the visual task, the higher the illuminance. In order to reproduce contrasts correctly, there must be as uniform an illuminance as possible in the work area. The nominal illuminance levels required for certain visual tasks are specified in DIN 5035. The nominal illuminance is defined as the recommended local and temporal mean value of the illuminance and relates to the mean age of the lighting system.

For general lighting purposes, the direction of light should be parallel to the direction of view. The interior lighting with daylight takes place through windows. In addition to lighting, these also have the important task of creating a visual connection between the workplace and the outside world. Since daylight is subject to great daylight and seasonal fluctuations, the daylight quotient was introduced to assess daylight. The intensity of daylight drops steeply towards the depth of the room, especially in deep rooms.

For artificial lighting, screen workplace lights (BAP lights) are often used. These luminaires must have a glare rating ( UGR value ) ≤ 19 in order to be officially designated as a BAP luminaire.

The spatial arrangement of the screen should ensure the maximum relief of the accommodation apparatus. The recommended distance between the eyes and the screen would therefore be around 50 cm, and around 70 - 80 cm for people aged 50 and over. The distance between the keyboard and the edge of the table should ideally be half a cubit so that the heels of the hands can rest comfortably.

Flickering light sources (also above the limit of the flicker fusion frequency ) have been shown to lead to faster fatigue of the eyes. So far, little attention has been paid to the fact that the combination of flickering lighting sources such as fluorescent lamps in connection with the use of flickering CRT screens can lead to eye problems. Presumably, the superposition of different flicker frequencies increases the signs of fatigue in the eyes.

It should be noted that not only CRT screens , but also fluorescent lamps with conventional ballasts flicker, which also leads to faster fatigue. This can be avoided by using electronic ballasts.

Office workplaces with multiple screens

With increasing digitization and networking of office work, the proportion of screen working time increases. The need for a usable screen surface is also increasing, since a number of programs or screen masks are used at the same time. Therefore, multiple screens are often used. Metrological studies have shown that, depending on the screen configuration and the type of task, the services provided varied qualitatively and quantitatively. Overall, the results of the physiological investigations and the preferences of the test subjects speak in favor of using double-screen variants instead of a single screen. There are hardly any physiologically limiting factors when working on double screens and there are also no indications of a possible risk from office work on double screens.

Health risks

18 million people in Germany work in the office and on screen, and the number is rising. Many of these employees often sit immobile in front of their desks for hours. The consequence of this forced posture: lack of exercise and insufficient demands on the muscles. In the long term, this can lead to chronic damage, including cardiovascular disease, type II diabetes and musculoskeletal complaints.

Individual evidence

  1. ↑ Council Directive 90/270 / EEC of 29 May 1990 [1]
  2. ↑ W. Jaschinski and M. König: See and work better on the computer: An Internet advice tool. Dortmund 2015: Leibniz Institute for Labor Research at the Technical University of Dortmund. Consulted September 7, 2015
  3. ↑ IAW Uni Bremen: Ergo-TIME ( Memento of the original from July 4, 2007 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. Online version from September 23, 2007. @1@ 2Template: Webachiv / IABot / www.iaw.uni-bremen.de
  4. ^ E. Lawrence Bickford: Computers and Eyestrain . Revised January 19, 1996.
  5. ^ German Social Accident Insurance eV: IFA - Work 4.0: New Forms of Work - New Office Worlds - Office workplaces with multiple screens. Accessed February 7, 2017 (German).
  6. ^ Deutsche Gesetzliche Unfallversicherung eV: DGUV: Press releases 2nd quarter 2015. Accessed on February 7, 2017 (German).