Work Station Design For VDU Operators: Part III

Photo Credit: www.theeyeclinicofnorthampton.co.uk

Screen

The VDU should be positioned at a distance of 35-60cm from the operator (70cm maximum). Ideally, the eyes should be depressed at an angle of 15-20 degrees.
The screen should be at right angles to the line of sight and it should be possible to rotate the screen laterally so that the operator is not disturbed by their own reflection. Displays that are lower than the seated eye height and within 60 degrees of horizontal line of sight are acceptable.

Keyboard

The keyboard height should be such that the operator's arms form angles of about 90 degrees at the elbow and allow the wrists to be slightly flexed. Ideally, the keyboard should be detachable, to allow the operator to find the best working position, e.g. it should not be placed too far from the desk edge as this results in a cutting action by that edge on the wrists and forearms. For tasks in which largely numeric data are being entered, an auxiliary numeric key set should be considered. The keyboard should have a slight slope and it should be as thin as possible. The keyboard should also have a matt surround and keys should have low reflectance surfaces.

Posture

The chair should have an adjustable seat height, adjustable back rest height and an adjustable tension on the back rest. The seat height should be such that the operator's legs form an angle equal to or greater than 90 degrees at the knee, with feet on the floor. This is generally achieved with the seat height being between 34 and 52cm. There should also be an adequate knee clearance between the seat and the table.

Work Tables and Desks

There should be sufficient space for documents, books and other ancillary equipment to be arrange as required. The work surface should be a minimum of 120cm long and 60cm wide, preferably 160cm long and 80cm wide. The work surfaces should also have a matt finish to prevent troublesome reflectances or glare. Document holders should be provided because they will prevent bending of the neck by the operator to read documents placed flat on the desk. The holders should be adjustable and can be placed next to the VDU screen at a similar angle, distance and height to give visual comfort.

Environmental Conditions

Office decor needs to be visually restful and glare-free. High reflectances walls, ceiling, or floor surfaces may lead to glare but low reflectance surfaces may create gloom. Therefore, large surface areas should be decorated in soft pastels or warm grey, i.e. have medium reflectance and low contrast. During extended periods of writing and reading, etc., unconscious involuntary relief for the eyes occurs by looking away from the task at distant objects. Paintings and foliage may be useful to provide visual relief.
Noisy equipment, such as printers, should be positioned away from the operator or soundproofed. A noisy terminal should be serviced by the supplier.

VDUs and light sources inevitably produce heat which, in warm weather or in confined spaces can become a real problem if the ventilation system is not able to cope. Many VDU operators complain of sore, dry eyes. This is generally due to a reduced blink rate, which occurs with intense concentration, and to the lack of humidity which is quite prevalent in many offices, especially those with air conditioning. This is particularly problematical for contact lens wearers. Therefore, adequate ventilation and reasonable humidity should be maintained to avoid such problems as drowsiness and dryness of the eyes.

Back to: Part I  or  Part II