Purpose
The purpose of this procedure is to provide guidelines and information to effectively set up a computer workstation in an office environment.
Scope
This procedure applies to all employees of our company including temps, trainees, work experience students, volunteers and clients.
Policy Statement
Poor job and workstation design, cramped conditions and poorly adjusted furniture can lead to fatigue, discomfort and pain. Well designed jobs and suitable workstations can improve efficiency and comfort for keyboard operators.
Common problems experienced by keyboard operators include the wrist, neck/shoulder, and lower back pain. These symptoms can be avoided by appropriate set-ups and work practices.
Keyboard
Place the keyboard in a position that allows the forearms to be close to horizontal and the wrists to be straight. That is, with the hand in line with the forearm. If this causes the elbows to be held far out from the side of the body then re-check the work surface height.
Chairs
A chair should both fit the person who sits in it and is appropriate for the task being carried out. However, prolonged sitting even in a suitable chair should be avoided. This means people should vary their work activities and posture frequently. Chairs (for workstations) designed using ergonomic principles should:
- Have a back rest that is easily adjustable in height and angle
- Have an adjustable back rest depth
- Preferably have a cloth covered seat and back
- Have a curved front edge
- Be height adjustable
- Have a five-star base for stability
Gas lift chairs are recommended for workstations with multiple users or when workers have a variation in a task that requires adjusting the height of the chair. For example, alternating between keying at a higher deck (seat set high and foot stool used), and writing and reading activities at a regular desk (normal height).
Gas lifts are used to make height adjustments quickly and easily and a screw adjustment is satisfactory if only one operator uses the chair at the same height.
Adjust the seat tilt so that you are comfortable when you are working on the keyboard. Usually, this will be close to horizontal but some people prefer the seat tilted slightly forwards.
The knees should be bent at a comfortable angle and greater than 90º flexion. If this places an uncomfortable strain on the leg muscles, or if the feet do not reach the floor, then a footrest should be used. The footrest height must allow the knees to be bent at 90º; the height of the footrest may need to be adjustable.
Adjust the backrest so that it supports the lower back when sitting upright.
Phones
Avoid cradling the phone between the head and shoulder when answering calls. If there is a need to keep the hands available during telephone conversations, use a headset or the phone’s hands-free/speaker-phone capabilities if the environment is suitable.
Monitors
The top of the screen should be at eye level and about 600 to 700 millimetres from the eyes when the neck is comfortable and the head is upright. This distance can vary due to individual preferences and other visual requirements such as short-sightedness. If the majority of time is spent looking at the screen, the keyboard and operator should be positioned in front of the screen.
Using a Visual Display Unit (VDU) does not harm the eyes. Reading is not an eye-damaging activity, however, it can result in eye muscle fatigue through constant use. If workers are over the age of 40 or experiencing eye discomfort or headaches, eye tests are a worthwhile exercise. The work environment should be evaluated for other problems such as glare.
Eye-strain can be reduced by proper adjustment of screen luminance and contrast. The contrasting background should be dark and the character luminance should be moderate (not high). Eye strain can be further minimised by the proper positioning of the screen in relation to other light sources.
Glare from windows or other bright sources of light may cause discomfort or reduced visibility. Avoid these problems by positioning the VDU so light is not within the ‘line of sight’ or reflected onto the eyes. Glare can also be minimised by reducing the intensity of the light source. Reflections on the screen can make images hard to see and may force people to adopt awkward postures to make the images easier to see. Minimise reflections by using a light screen background colour, a flat screen, or positioning and screening off sources of reflection.
Document Position
Documents left flat on the desk top and off to the side encourage extreme neck postures and cause neck strain. The use of a document holder can better position documents and so minimise the likelihood of neck strain.
Documents should be placed in either a level position beside the screen or directly below the screen. If most time is spent looking at the document (not the screen), the document should be placed directly in front of the operator. If approximately half the time is spent looking at the document the document and screen should be at an equal distance from the eyes. If most time is spent looking at the screen, the screen should be placed directly in front of the operator.
If the document has to be handled frequently, place it on the dominant (right or left) side or centrally.
Desks
As with chairs, desks should accommodate both the characteristics of the worker using it and the tasks they perform. Using desks of the right height help to reduce strain on the spine, shoulder and neck muscles.
Keyboard work requires a keyboard height just below elbow height of the operator. As a guide, the approximate height range should be from 640mm to 690mm. This allows workers to type with shoulders relaxed and elbows by their side bent at a right angle. To achieve this a height adjustable desk is usually required.
Other tasks, such as reading and writing, require a height just above elbow height of the worker. As a guide, the approximate height range should be from 700mm to 760mm. This allows elbows to be rested on the desk. Desks that cannot be adjusted in height designed to suit the majority of users are suitable for most workers.
Sit/stand desks
Sit-stand workstations are one of a variety of ways to reduce sedentariness. They shouldn’t be considered a ‘fix all’ for obtaining adequate physical activity over the course of the day and should be supplemented with a healthy lifestyle and other strategies for sitting less.
The cost of a sit-stand workstation, any office modifications required, and additional assistive equipment will need to be met by the work area.
Sit-stand workstations can in some instances aggravate existing injuries/medical conditions or present a risk for new injury. For example, lower back, knee and ankle injuries, as well as conditions such as arthritis, can be aggravated by increased standing. It is important that the implementation of a sit-stand desk is in line with an employee’s treating health practitioner’s recommendations.
Lighting
Place the monitor to the side of the light source/s, not directly underneath. Try to site desks between rows of lights. If the lighting is fluorescent strip lighting, the sides of the desks should be parallel with the lights. Try not to put the screen near a window. If it is unavoidable ensure that neither the screen nor the operator faces the window.
If the monitor is well away from windows, there are no other sources of bright light and prolonged desk-work is the norm, use a low level of service light of 300 lux. If there are strongly contrasting light levels, then a moderate level of lighting of 400-500 lux may be desirable.
Glare and Reflection
It is important to detect the presence of glare and reflection. To determine whether there is glare from overhead lights, sit down and hold an object such as a book above the eyes at eyebrow level and establish whether the screen image becomes clearer in the absence of overhead glare.
To detect whether there are reflections from the desk surface, hold the book above the surface and assess the change in reflected glare from the screen.
You can eliminate or reduce the influence of these reflections in a number of ways:
- Tilt the screen (top part forwards) so that the reflections are directed below eye level.
- Purchase an LCD screen.
- Cover the screen with a light diffusing surface or anti-glare screen.
- Negative contrast screen (dark characters on light background) will reduce the influence of these reflections.
- If you experience eye discomfort when using a bright screen you should make the following adjustments:
- Turn the screen brightness down to a comfortable level.
- Look away into the distance in order to rest the eyes for a short while every 10 minutes or so.
- Change the text and background colours. We recommend black characters on white or yellow background, or yellow on black, white on black, white on blue and green on white. Avoid red and green and yellow on white.
Mouse and Trackballs
The mouse should be positioned to allow workers to use it with their elbow held close to their side and with the shoulders in a comfortable position. Often a keyboard may need to be repositioned so that a mouse can be placed appropriately.
If the desk space is too small to use a mouse, a trackball is a good alternative.
Workers should not use a mouse on a desk surface higher than keyboard height.
Worker Positions and Postures
Good postures place the body in “low stress” positions and allow for more comfortable and efficient work. The most commonly used postures in the office are sitting and standing, but workers also may need to reach, kneel, or stoop, such as when ‘unjamming’ a photocopier.
A good ergonomics principle is to keep as close as possible to a ‘neutral position’. For the arms ‘neutral’ is when they are hanging down beside the body. The body normally adopts a neutral posture when relaxed in a comfortable, supported position.
Postures that are ‘low stress’ are also recommended. Low-stress postures generally:
- Do not overload any part of the body (neck, lower back, etc)
- Are comfortable
Minimise fatigue
Stress on the body is increased when the:
- Body is held in one position for a long time
- Body or head is tilted over for an extended period
- Joints are moved to as far as they can go
- Work occurs with joints away from ‘neutral’ position, for example, wrists extended back
- Body parts such as wrists or back are rapidly twisted while exerting force or holding loads
- Loads are held in static positions, such as holding a heavy box while waiting for a space to be cleared to put it down
- Movements are repetitive (too fast, too hard, too long)
Prolonged Keying
Prolonged keying without a break must be avoided. Whenever possible, tasks should be varied to allow different muscles to be used and tired muscles to recover.
The more varied the tasks the lower the risk of injury. Examples of such break out tasks may include filing or photocopying, collecting or delivering documents that allow standing or walking. Writing should not be performed during such breaks.
The social and psychological aspects of office work also may affect the health of workers. This may include work load demands, control over the work, participation in decision making, personal space and social interactions.
Rest Breaks
Where tasks are similar in nature and alternative tasks are not available, it is important to have more set rest breaks away from work. Ideally, the job should be redesigned to include more variety of work to provide rest for body parts under stress. If there are no suitable alternative work tasks when carrying out repetitive work, such as data entry, work pauses should be provided.
Rest breaks can vary from micro pauses such as waiting for a computer screen to come up, through to defined breaks such as morning tea or lunch. A break from a task to answer the phone or to get a glass of water also provides rest and recovery for muscles and body parts that have been active. A selection of these breaks should occur throughout the work day.
Rest breaks do not need to break from productive work. A change of task for a few minutes is a very effective rest break for the body. Check however that the ‘different’ task really is different for the parts of the body that are under stress. Some job rotation schemes move employees around to similar work. For example, keying and writing both use similar small hand muscles.
It should not be necessary to have pause gymnastics, stretches or exercises in your work routine where a variety of tasks and appropriate rest breaks are provided. When setting work hours or arranging overtime, also consider the amount of accumulative stress the task is placing on the body. As the working day extends it is even more important to have task variety, rest breaks and postural variation.
Documentation
Risk assessment