At Auckland Therapeutic Massage we do focus a lot on our customers sporting achievements, but let’s not forget that very much the majority of us a weekend warriors, who do have to hold down a job during the week! If you are into all your sporting stuff, this usually means we are keeping the body in reasonable shape, but what if you come home after a long day at work literally with a pain in the neck ? Is your desk set up properly ? Are you sitting well ? Or is your job slowly killing you?
I recently took this question to ACC (the horse’s mouth ?) and received a 20 page ‘ Computer guidelines short version’, I will put excerpts at the end of the newsletter for your perusal.
So obviously there is quite a lot to say about the subject! In a nutshell I would like to add that you can always come for a massage and I am sure it will be as good a use of your time as reading the guidelines (or perhaps better 🙂
Best as always,
ACC : Computer guidelines
In the past three decades computers have significantly changed the working
environment, simplifying and speeding up many tasks across many work areas.
However, with these advances have come some potential health issues.
This document provides an overview of key information relating to preventing and
managing discomfort, pain and injury associated with the use of computers. For more
detailed information, please refer to ACC’s ‘Guidelines for using computers: Preventing
and managing discomfort, pain and injury’ (the Computer Guidelines – ACC 5637).
The Computer Guidelines describe how managers, health and safety representatives,
occupational health and safety personnel, human resource personnel and computer
users can work together to achieve a healthy and productive workplace. The guidance
reflects current knowledge and best practice for the use of computers so that you
can achieve maximum efficiency, safety and health in your workplace. The guidelines
replace the ‘Approved Code of Practice for the Use of Visual Display Units in the Place
of Work’, published by the Department of Labour in 1995.
Using the guidelines
The Computer Guidelines provide recommendations to help computer users stay
comfortable and productive. We encourage a collaborative approach between workers
and managers to achieve the most effective use of computers in the workplace.
Layout of the guidelines
The Computer Guidelines present a hazard management process that helps you to
identify hazards associated with computer use and assess their significance. They
also present controls to eliminate, isolate and/or minimise the hazards. The hazard
management process takes you through five key steps:
1. Identifying and understanding potential health issues;
2. Assessing potential hazards;
3. Controlling hazards;
4. Managing potential health issues;
5. Health monitoring and programme review.
The Computer Guidelines (ACC 5637)
replace the ‘Approved Code of Practice
for the Use of Visual Display Units in
the Place of Work’ (1995).
What is a computer workstation?
Typically this encompasses the computer
and the workstation furniture, such as
the desk, chair, any equipment used (e.g.
telephone, document holder and printer)
and the environment (e.g. lighting,
ventilation and noise).
Who should use the guidelines?
Anyone who uses a computer, or
manages people who do, will find the
guidelines helpful.2 Short guidelines for using computers – preventing and managing discomfort, pain and injury
potential health issues
Four potential health issues are associated with computer work:
» Physical discomfort, pain or injury;
» Visual discomfort;
A range of physical conditions may develop or be made worse by working with
computers. Many people experience upper limb, neck or back discomfort and pain,
whether or not they work with computers. However, the onset of symptoms and the
movements or body postures adopted while working at computers are often related.
Symptoms can include:
» Muscle discomfort;
» Burning sensations;
Sometimes computer users find that these sorts of symptom worsen during the day or
week and, at least initially, improve at weekends and holidays. It is important to act as
soon as symptoms present. Small changes made at the first indications of discomfort
usually produce the best outcomes and can stop more significant problems from
Eye discomfort is a common health problem experienced by computer users.
Eyesight naturally deteriorates with age. However, several long-term scientific studies
comparing computer users and non-computer users have shown that these changes
are not necessarily increased through computer use.
The symptoms of visual discomfort vary and include:
1Short guidelines for using computers – preventing and managing discomfort, pain and injury 3
» Sore eyes;
» Red eyes;
» Watery eyes;
» Dry eyes;
» Eyes feeling ‘heavy’ or ’gritty’;
» Blurring of vision;
Workers may also experience visual discomfort from:
» Uncorrected eyesight problems that become apparent with computer use;
» Visual changes with aging;
» Wearing glasses or contact lenses that are not suitable for computer work;
» Inadequate lighting (too little or too much, or the position and type of lighting);
» Poor computer workstation set-up;
» Lifestyle factors, e.g. smoking, lack of sleep.
Stress can occur in a wide range of computer use situations. It can be made worse
when the demands and pressures of work do not match the computer user’s
knowledge, resources or abilities. Stress may also occur when the computer user feels
unable to cope or that they have little control or social support.
Symptoms of stress can include:
» Increasing distress and irritability;
» Physical aches and pains;
» Difficulty relaxing, concentrating or sleeping;
» Difficulty thinking logically and/or making decisions;
» Decreased enjoyment of work and/or feeling less commitment to work;
» Feelings of tiredness, depression or anxiety.
Workplace stressors may be inevitable or avoidable. Inevitable stressors can include:
» Starting a new job;
» Learning a new skill;
» Fluctuations in work flow;
» Unpredictable emergencies in the workplace.
Avoidable stressors can include:
» Working for too many hours each week;
» Working in a situation that is poorly set up for the work being done;
» No performance feedback or only adverse feedback.
Stressors are events or circumstances that
may lead to the perception that physical
or psychological demands are about to
Types of stress
Stress is not just restricted to the work
environment – pressures at home can be
a contributing factor. Therefore, good
support both outside work and in the
workplace may strengthen a worker’s
capacity to deal effectively with work
Further information about stress
A number of organisations provide
information for the prevention and
management of stress, e.g. New Zealand
Department of Labour, the Preventing
and Managing Discomfort, Pain and
Injury Programme (www.acc.co.nz/
dpi), the World Health Organization
publication ‘Work Organisation and
Stress’, the International Labour
Organization (ILO) website on Safe
Work: Stress at Work (www.ilo.org/
stress/index.htm) and the European
Agency for Safety and Health at Work
website on stress (http://osha.europa.
eu/en/topics/stress).4 Short guidelines for using computers – preventing and managing discomfort, pain and injury
Fatigue can take a number of forms.
Physical fatigue is probably the most familiar and, in terms of physically demanding
jobs, tends to be naturally self-limiting. However, in sedentary computer use the
physical fatigue of smaller postural and arm muscles might not be recognised until the
onset of discomfort or pain.
Mental fatigue can occur after long periods of computer use without the user being
aware of their developing symptoms. To combat mental fatigue, preventative strategies
should be targeted at managing tasks during the day to allow mental resources to be
allocated and used effectively.
Emotional fatigue can result from the need to complete tasks where mental fatigue
is involved and is coupled with the uncertainty of emotional responses. For example,
working as normal when a restructuring programme is taking place and a job is
perceived as under threat can be very difficult. Other sources of emotional fatigue are
mentioned under the headings of ‘work organisation’ and ‘psychosocial’ factors.
What are the sources of these health issues?
Contributory factors thought to lead to discomfort, pain and injury in computer users
can be grouped into seven categories:
» Work organisation;
» Work layout/awkward posture;
» Task invariability;
» Load/forceful movements;
» Environmental issues.
All these factors need to be considered together to prevent or reduce the incidence
of discomfort, pain or injury. Research shows that you’ll get better results by making
small, positive changes to a number of these factors than by focusing on one or two.
Are computer-related health issues solely
related to workplace computer use?
Computer-related health issues are not only work related – many people use computers
at home, when travelling or for gaming. The problems that may develop from
computer use can also be caused by domestic or recreational activities that use similar
muscle groups or positions, e.g. knitting, model making. Health issues may arise as an
accumulation of all activities undertaken.
A temporary inability or decrease in
ability to respond to a situation because
of previous over-activity. This overactivity
may be physical, mental or
emotional in nature.
These are not listed in any order of
importance, as the impacts of each
group will vary for different work
Further information on
You can read more about the seven
groups of contributory factors in
‘Preventing and Managing Discomfort,
Pain and Injury’ (ACC) and
‘HabitAtWork: Managing Discomfort,
Pain and Injury in the Office’ (http://
habitatwork.co.nz/index.html).Short guidelines for using computers – preventing and managing discomfort, pain and injury 5
Benefits of working safely with computers
The potential benefits of best practice for computer use include:
» Less discomfort, pain and injury;
» Reduced absenteeism;
» Reduced costs of staff replacement and training;
» Increased efficiency and improved quality (work completed more quickly and with
» A harmonious work environment.
You’ll get the best results from your programme of managing and reducing the
hazards of computer-related health issues when you demonstrate your commitment to
the whole process. This requires:
» Both you and senior managers in your organisation to be involved in health and
» An open management style;
» Two-way communication between staff and management, which encourages ownership
of problems and better management of them;
» An appropriate balance between health and safety and business goals;
» An environment that encourages the early reporting of discomfort and any
ACC has developed a ‘cost calculator’
that can help you to determine the costs
of injuries and the benefits of making
changes to your workplace (www.acc.
injury-cost-calculator/PI00079).6 Short guidelines for using computers – preventing and managing discomfort, pain and injury
To assess the hazards involved with computer work, you need a systematic process
to identify and prioritise them. You also need to develop an action plan to control the
hazards you find. You can do this any time: when your workplace is already set up,
when you plan to move to new premises, or when you update your existing premises.
Changes in technology or work processes are likely to bring about the biggest
changes in computer users’ exposure to hazards. As the work changes, the impacts
of associated hazards may also change, so you need to complete hazard assessments
The hazards likely to arise from computer work can be grouped according to:
» The way the work is organised;
» The work environment, e.g. lighting, noise, thermal comfort;
» Postures and practices;
» The selection and arrangement of furniture and equipment;
» The selection and arrangement of computer hardware;
» Education and training.
To identify hazards you need to:
» Review early report forms;
» Review records for previous health issues, e.g. accident reports, ACC claims;
» Observe the ways that computer users actually perform their computer work, as
these may differ from those reported by the computer users or others involved in
» Consider the types of task that will be required and the set-up of workstations;
» Take account of the preventative or control measures you already have in place.
If existing measures are not adequate, you may need to identify further measures
you can put in place;
» Work jointly with computer users.
Hazard assessment checklist
One way to highlight hazards within your workplace is to use a hazard assessment
checklist. A checklist is a particularly valuable tool. It provides a systematic approach
to hazard identification so that none of the hazards are overlooked.
The hazards arising from computer
work reflect many of the contributory
factors for discomfort, pain and injury
Health and Safety in Employment
Section 6-10 of the Health and Safety
in Employment Act 1992 outlines the
requirement to eliminate, isolate or
minimise hazards in the workplace.
A ‘hazard that is an actual or potential
cause or source of:
a) Serious harm; or
b)Harm (being harm that is more than
trivial), the severity of whose effects
on any person depend (entirely or
among other things) on the extent or
frequency of the person’s exposure to
the hazard; or
c) Harm that does not usually occur, or
usually is not easily detectable, until a
significant time after exposure to the
Health and Safety in Employment Act
1992Short guidelines for using computers – preventing and managing discomfort, pain and injury 7
The computer workplace can present a number of hazards. While you may be able to
eliminate some hazards, in many cases it will only be possible to isolate or minimise
You’ll find many hazards quick and easy to deal with, but some will be more
challenging. For example, purchasing new furniture is often costly and may require
This is why you need to decide which hazards to deal with first. Involve your computer
users in the prioritising process, because they can tell you which hazards are affecting
them the most.
Developing a hazard control plan
Once you’ve determined how you are going to tackle the hazards, draw up an action
plan. Your plan should record all significant findings from the hazard identification you
have just completed. It should also include:
» Preventative and protective measures you will implement to eliminate, isolate or
minimise the potential harms associated with each hazard;
» What further action, if any, is needed to eliminate, isolate or minimise each hazard;
» The timeframe in which you will implement these preventative or protective
You need to review and monitor your action plan regularly to ensure that the actions
you have proposed are implemented and/or re-prioritised if necessary.
The hazards you prioritise first should
include those that:
• Are most likely to cause injury or
• Can be addressed quickly and easily;
• The computer user feels are most
• Provide clear benefits in relation to
the costs involved in implementing
solutions.8 Short guidelines for using computers – preventing and managing discomfort, pain and injury
Here is a guide to some common factors that give rise to hazards associated with the
use of computers (Figure 2). Also included is information about how hazards can lead
to potential health issues and recommendations on how you can prevent or reduce the
risks arising from these hazards.
Figure 2. Factors to consider when using computers
One of the most important things affecting computer users is the way their work is
structured and managed.
Well organised work should:
» Recognise the experience and capabilities of computer users and match work
demands to these;
» Ensure that there are sufficient resources and time to do the work at all times;
» Allow each user to apply a variety of skills and capabilities and undertake a range
» Give computer users a sense of the contribution they are making to the overall
output of the organisation;
» Allow users appropriate control over the priority, pace and procedure;
» Encourage two-way communication and participation and provide sufficient
feedback on task performance and management;
» Provide opportunities for users to develop their existing skills and build new skills;
» Develop a supportive workplace culture through encouraging participation,
initiative, cooperation, feedback and teamwork.
Hazards associated with computer work
will vary depending upon individual work
‘User participation in the implementation
process is of particular importance with
respect to effective implementation and
functioning of the system.’
ISO 9241-2:1992Short guidelines for using computers – preventing and managing discomfort, pain and injury 9
Things to avoid:
» Overload or underload, which can lead to unnecessary or excessive stress or
» Undue repetitiveness, which can lead to excessive strain, monotony or
» Undue time pressure, which can lead to stress, fatigue or errors;
» Working alone without opportunities for contact with others within or outside the
» Conflicting communication and/or expectations.
The work environment
Maintaining the best possible work environment is essential to ensure the health and
productivity of all computer users. Lighting, thermal comfort, air quality and noise are
key aspects of a good work environment.
Poor lighting can cause symptoms of visual discomfort, headaches and migraines.
Lighting that causes shadows or glare can also result in awkward working postures as
computer users try to get a clear view of their screens or documents.
Aspects of lighting you need to consider include: illuminance levels; uniform
illumination; colour appearance; colour rendering; glare and reflection; flicker; and
maintenance of lighting.
To achieve appropriate lighting you need to think about how you have positioned
workstations in relation to windows or skylights:
» Where possible, position workstations at right angles to windows;
» Windows and skylights should have adjustable blinds or drapes to control excess
» Consider window coatings that can reduce glare.
You also need to think about how workstations are positioned relative to overhead
lighting. As far as possible, position workstations:
» Parallel to, and between, rows of overhead lights;
» So that overhead lights are not directly within users’ visual fields when they look at
» So that overhead lights are not directly behind the computer workstations (to avoid
Also ensure that lights near computer screens are fitted with diffusers, cube louvers or
The design and arrangement of the
work environment are governed by a
combination of factors, including work
organisation, communication and an
individual’s ‘personal environment’.
The intensity of the light falling on a
surface is called the ‘illuminance’ and is
measured in units of lux.
For most computer tasks, the average
illuminance level should be at least 320
In some instances, higher levels of
lighting (600 lux or more) will be
appropriate, e.g. for visually demanding
For further information on the lighting
of interior workplaces, refer to
AS/NZS 1680 (Parts 0-4), ISO 8995
2002, and ISO 9241-6:1996.10 Short guidelines for using computers – preventing and managing discomfort, pain and injury
Thermal comfort and air quality
Thermal comfort refers to a person’s satisfaction with their thermal environment. If
workers are not comfortable with their thermal environment they may become tired,
irritable or less productive. This can result in a high number of errors.
A person’s comfort is not determined by air temperature alone. A combination of
factors influences thermal comfort, including:
» The level of activity during work;
» Air temperature, speed of air movement and humidity;
» Radiant sources of heat and heat from office equipment;
» Insulation from clothing;
» Personal preferences.
Temperature and airflow
Thermal comfort can be very subjective, with people’s perceived levels of thermal
comfort varying significantly. You may find it difficult to suit everyone’s preferences.
You may need to lower air temperature and increase airflow to suit individual users if
their work involves more physical activity (e.g. warehouse work). In extreme thermal
environments you may need to provide appropriate clothing.
The relative humidity (RH) of the working environment directly affects people’s
perceptions of comfort. Humans need an RH of 40 percent to prevent the mucous
membranes in the mouth, nose and eyes drying out. Humidity levels that are too high
can lead to feelings of stuffiness and fatigue.
Air quality and ventilation
People react strongly when they think air is stuffy, stale or polluted and may express
this as general dissatisfaction with the environment.
Sources of pollution in buildings may be internal, external or structural. Office
machinery and fittings, such as photocopiers and laser printers, carpets, wall
coverings, particleboards and cleaning materials may emit a variety of substances such
as ozone, formaldehyde and solvent vapours.
You can use natural or mechanical ventilation, or a combination of both, to remove
these substances. Note that inadequate flow rates are associated with a decrease in
perceived air quality, increased short-term sick leave and reduced productivity.
You may need to seek expert advice to sort out air quality problems, especially if your
buildings are air-conditioned.
Recommended temperature and
During summer (when workers wear
light clothing) the air temperature should
be between 23°C and 26°C, and the
average airflow velocity between 0.1m/s
and 0.25 m/s.
During winter (when workers wear heavy,
winter clothing) the air temperature
should be between 20°C and 24°C and
the average airflow velocity between
0.1m/s and 0.15m/s.
The amount of water vapour in the air.
Relative humidity (RH)
The current level of water vapour in
the air compared with the level of water
vapour that would completely saturate
the air. RH is expressed as a percentage.
Recommended RH levels according
Air temp RH
Recommended air flow
A minimum flow rate of 10 litres
per second per person is based on
recommendations of NZS 4303:1990.
More recent research by the European
Multidisciplinary Scientific Network
on Indoor Environment and Health
(EUROVEN, 2002) suggests that flow
rates should be closer to 25 litres per
second per person.Short guidelines for using computers – preventing and managing discomfort, pain and injury 11
In most cases, noise in the office environment (office equipment, ringing phones, air
conditioning/fans, work colleagues) is unlikely to reach levels that are hazardous to
hearing. However, office noise can make communicating and concentrating difficult,
and may consequently be a source of stress.
Measures you can use to reduce noise:
» Padding under machines;
» Enclosing noisy machines in acoustic hoods;
» Carpeting the floor;
» Installing sound-absorbing partitions;
» Installing acoustic ceiling tiles;
» Repairing, replacing, isolating or relocating noisy equipment;
» Lowering the ringer volume on telephones;
» Using telephone headsets rather than speakerphones;
» Providing specific meeting areas that are isolated from normal work areas.
Postures and practices
The postures and practices a person adopts throughout the day can significantly
impact on their risk of developing computer-related health issues. Risks can be
reduced by maintaining good postural habits and working practices, and by having an
appropriate workstation set-up.
A workstation that is arranged for maximum efficiency and comfort encourages the
computer user to adopt a range of well supported postures. Staying in the same
posture for long periods is undesirable. People naturally need to change position and
Reference postures and frequent changes to
Musculoskeletal stress and strain is reduced when the body works in neutral positions.
(A neutral body position is a comfortable working posture where joints are naturally
aligned.) Note that this is only one factor of many that can help to reduce a computer
worker’s risk of developing discomfort, pain or injury related to their use of a
Figure 3 shows a range of acceptable postures that computer users may adopt as
starting positions to move in and around. Note that there is no uniquely correct
posture that would suit any user for an extended period of time.
Humans are designed to move and change position, and their work environment
should enable and accommodate changes in posture. Computer users should also be
encouraged to change their working positions frequently throughout the day.
The recommended maximum average
level for background noise is 45dBA at
the position of the computer user.
‘Users require frequent movement
and postural changes to achieve and
maintain comfort and productivity. The
four reference postures are intended to
illustrate the diversity of body positions
observed at computer workstations.’
‘Movement should be encouraged by
considering job content and furniture
design. This means that prolonged
static sitting posture is minimised and
that more or less continuous voluntary
adjustments of the position of the lower
limbs and upper body can be made.’
ISO 9241-5:199812 Short guidelines for using computers – preventing and managing discomfort, pain and injury
Figure 3. Reference postures
Rearward Tilt Sitting Upright Forward Tilt Standing
Recommendations for computer users who sit to work:
Legs and feet
» The feet are fully supported by the floor. If the feet cannot be supported on the
floor, a suitable footrest should be used.
» The knees are the same height as, or just below, the hips, with the feet slightly
forward of the knees.
» The bottom and thighs are supported by a well padded seat approximately parallel
to the floor.
Neck and back
» The head is level or bent slightly forward, forward facing and balanced. Generally it
should be in line with the torso and not turned to one side.
» The back is positioned so that the natural curves of the spine are maintained in
both the upper and lower regions of the back.
» The back is fully supported with appropriate lumbar support when sitting upright
or leaning back slightly.
Arms and hands
» Shoulders are relaxed.
» Elbows are hanging comfortably by the user’s sides.
» Elbows are close beside the body and at approximately right angles. If the user is
reclining in their chair, a greater elbow angle is appropriate. Recommended elbow
angles range between 70° and 135°.
» The hand or forearm is supported.
» Wrists are as straight as possible, within 30° up or down (extension and flexion).
» Avoid sideways bending of the wrist (ulnar/radial deviation).
» Direct pressure on the under surface of the wrist should be avoided while typing or
using a mouse or pointing device.
» Fingers should remain relaxed and slightly curved rather than excessively arched or
extended during typing.
» When in use, a mouse should be held loosely in the hand, with the fingers and
thumb relaxed so that they are gently resting against the mouse.Short guidelines for using computers – preventing and managing discomfort, pain and injury 13
Standing to work
Many people find standing a comfortable way to work. However, long periods of
standing can be uncomfortable and may make certain back conditions worse. Where
people stand to use a computer, make sure that they do so for short periods, and that
they can easily move their legs. It is recommended that standing to work at a computer
be alternated with seated work.
Recommendations for the working posture of computer users who stand to
» Follow the same guidelines for upper body postures as outlined for the seated
position, e.g. head level, relaxed shoulders, arms hanging by side, elbows close to
» Provide sufficient knee and foot room. It should be possible to move the feet
forward or bend the knees to allow the user to lean forward and support their
upper body against the work surface;