Office Ergonomics - Part 2
Workstation equiptment in detail
See below for further details of workstation equipment and the office work environment
The Chair Click here for more details
The Seated & Standing Desk Click here for more details
The Monitor Click here for more details
The Footrest Click here for more details
The Keyboard Click here for more details
The Mouse Click here for more details
The Document Holder Click here for more details
The Laptop Click here for more detail
The Desk work surface Click here for more detail
The Environmental Factors Click here for more detail
(For Part Three - Preventing Pain click here )
You can create a work environment that is not only well set up, but also pleasant place to work in!
A good office chair should have three separate adjustments:
(a) The adjustment for seat height.
(b) The adjustment for backrest angle (as well as backrest height).
(c) The adjustment for the seat pan angle (i.e the part you sit on).
While most modern office chairs comply to the standard specifications, a good chair supplier should also be able to offer the following optional extras to best accommodate your individual needs:
- A longer seat pan option - for longer legs
- A wider seat pan option - for wider pelvis
- A softer seat pan option - for coccyx problems
- An adjustable lumbar support option - for firmer lumbar support
- An extra height option - for taller people
The Seated Desk
While Office Desks come in all shapes and sizes there are some recommended dimensions that should be adherred to:
- Minimum Depth 800mm for flat screens, 950mm for CRT screens
- Height adjustable range 610mm - 760mm for seated work
- Fixed height range 680 - 735mm
- Desk width 1200mm for computer work alone, 1600mm when combined with clerical work.
Other points to check are:
- Are the edges and corners of the desk rounded to avoid point pressure on hands, wrists and forearms?
- Is the surface of the desk a light, neutral colour?
The Standing Desk
The newer style standing
(or seated) desk
The Height adjustable range for a seated and standing desk should be 650mm - 1100mm.
Points to keep in mind when using a standing desk are:
- Follow the same guidelines for upper body postures
- Ensure sufficient knee and foot room
- Ensure sufficient space behind and to the side of the user to allow them to move freely
- Ensure a footrest is provided that allows the user to raise one foot off the ground
- Ensure a chair is still available to allow the user the option of sitting (with desk lowered)
- Consider shoe or floor cushioning (eg matting that is suitable for both standing and chair)
The Flat Screen Monitors widely used these days, with its much narrower profile, makes it much easier for the monitor to be positioned far enough away from you, at the back of your desk. This distance should be approximately an arms length (450 - 800mm) away from you. If too far away, it may cause eye tiredness or you may find yourself straining your neck foward to get better eye focus.
Flat Screen Monitors usually have some vertical adjustment, but a height-adjustable Monitor Stand will provide the best solution to obtaining the correct vertical positioning of the screen.
Raise (or lower) the monitor, or height-adjustable stand so that the top of the screen is approximately horizontal with your eyes.
Things to keep in mind:
The Foot Rest
A good Foot Rest can improve Workstation set up in two ways:
- It can correct leg support and relieve any pressure on the back of the legs (hamstrings), especially when the desk height is not adjustable.
- It can also help your body to maintain a slight backward pressure into the backrest of your chair.
A good Foot Rest should have the following features:
- All 4 legs fully height adjustable: typically 50mm to 185mm
- Variable foot platform slope of 0 to 15 degrees
- Foot surface area of 450mm wide x 350mm deep
- Good quality high friction material so feet don't slip off.
When positioning your Foot Rest, ensure the following conditions are met:
There are many different shapes and sizes of keyboards availiable today and choosing the right one for you should take into account:
- Your body width (i.e how far apart are your hands when resting straight in front of you on your desk?)
- The type of work you use the keyboard for (e.g. general word documents, gaming, multi-media or lots of data entry?)
- Whether you prefer a cordless or a plug-in type keyboard.
- Whether you prefer a 'clicking' sound during typing, or ones that have a softer touch and the keys are easier to depress.
Consult your local Hardware supplier and let them know what sort of work you are doing with your keyboard before choosing a keyboard for your particular requirements.
Wrist Positioning - (Correction of Wrist Adduction)
|If you find that when you place your hands on the keys of your keyboard, that your wrists are having to be held at an unnatural angle, then a keyboard, like this one (to the left) which can be adjusted to different angles, will make it possible for you to type and still keep your wrists in a straight and more natural position.|
Wrist Positioning - (Correction of Wrist Extension)
Good wrist positioning also means keeping your wrists in a good straight natural position while typing and trying to avoid the incorrect angled (or wrist extension) position.
|A useful hardware addition can be the Wrist Pad which when placed in front of the keyboard can help prevent such a sharp wrist angle from occurring while still giving a comfortable support to your wrists when at rest.|
Choosing a mouse can be just as challenging as choosing a keyboard. Some of the things that you need to consider are:
- Do you prefer an optical or a ball tracking mechanism?
- Do you prefer a mouse with a cable connection or a wireless connection?
- What sort of work are you doing with the mouse? (e.g. Point and click, high resolution graphics work or gaming).
- Would the size of your hand mean you need a large (or small) mouse?
Consult your local Hardware supplier and let them know what sort of work you are doing with your mouse before choosing a mouse for your particular requirements.
Wrist Positioning - (Correction of Wrist Extension)
|The ordinary style of mouse does mean that the wrist joint is held in a raised position (Wrist extension) for long periods of time.|
|One way of reducing this wrist angle is to use a Mouse Gel pad as part of your Mouse set up.|
Wrist Positioning - (Neutral Forearm Position)
|The ordinary style of mouse also means that your forearm bones (Ulna and Radius) are held in a twisted position, often for quite long periods of time.|
The new Vertical style of mouse (see left) allows your arm to be positioned in a much more neutral "handshake" position, as well as allowing the side of the hand to carry the weight of the hand, instead of placing pressure on the Carpal tunnel area of your hand.
The Document Holder
Once again there are a variety of shapes and sizes when it comes to choosing a Document holder. The size of the documents you are coping from will determine the size you need.
Positioning of the Document Holder
|If you have a free-standing type of Document Holder then, if possible, position this immediately behind the keyboard but in front of the monitor. This position will reduce the need to rotate your neck to look between the Document Holder and the monitor screen if it was positioned to the side of your desk. It also doubles as a sturdy writing surface if written entries are also required.|
|If a side mounted Document Holder is used then make sure it is about the same height and distance as the monitor screen (ie same focal length for your eyes), and that it is close beside the monitor screen. Generally these sort are only suitable for copying from lighter paper files, rather than books.|
While the Laptop is a great portable device, it should not be used as your primary computer at your desk as, on its own, it can compromise good ergonomic posture.
The way around this is to have your Laptop mounted on a simple Laptop stand so that the monitor screen can be adjusted to the correct height and distance away (see the Monitor section). Then, connecting a separate keyboard and mouse to the Laptop will allow for correct egonomic posture to be regained.
|Some of these Laptop stands fold neatly down so that they can be carried in your laptop satchell.|
Transporting your Laptop
|Remember,when it comes to transporting your laptop, its much better, ergonomically speaking, to place it in a Laptop Backpack so that the load is evenly distributed across both shoulders. This will save you a lot shoulder or wrist pain, especially if you are walking some distance with it and using a normal briefcase.|
Desk Work Surface Areas
Your desk can be divided up into three separate Work Zones semi-circles:
- Primary Work Zone - where most frequent tasks are performed
- Secondary Work Zone - where the occasional task is performed (e.g. In/out Trays)
- Tertiary Work Zone - where very rarely any task is performed (e.g. adjusting monitor height)
The location of frequently-used devices (e.g.keyboard, phone, and mouse) should always remain within the Primary Work Zone.
The Environmental Factors
There Three main factors which should be considered with your Workstation set up:
- Thermal Comfort & Air Quality
The normally recommended illuminance at clerical workstations is 500 lux (lux is a measurement of light intensity)
After ensuring there are correct light levels, the two main visual problems for VDU users are:
- Reflections off the screen
|Reflections are most frequently caused by poor placement of the monitor in relation to windows or bright lights. Where possible, the screen should be placed at right angles to the window or source of bright light. Also be aware of the positioning of overhead lighting as this too can be a cause of screen reflections.|
- Direct glare from bright lights in the field of view.
|Whilst the view may be great, sitting directly in front of a bright light source (like a window), it is not good on your eyes when focusing on the monitor screen. It is always much better to position your desk side on to the source of bright light.|
In a modern open-plan office, noise can be distracting and stressful. A calm and composed office is a healthier and safer office.
Office noise can be separated into three categories;
- ambient - background office noise (eg photocopiers, keyboards, airconditioning, people movement etc)
- transfered - either airborne or by direct transfer, perhaps through a surface (eg an internal meeting room wall).
- external - noise generated from the external environment (eg traffic noise).
Some of the actions that you could to to minimise office noise are:
- Separate desks as much as possible.
- Locate printers away from your desk
- Use adjustable volume controls on telephones
- Make use of quiet rooms and/or meeting rooms for uninterrupted phone conversations and meetings.
3.Thermal comfort and Air Quality
Obviously air temperature is a very significant factor in terms of thermal comfort. Generally, the colder the air temperature, the greater the rate of heat loss. Also air speed creates a cooling effect on the surface of the skin, so that sitting in a draft, where air speeds are higher than usual, can have a very cooling effect.
Air temperature values are recommended to be:
Summer - 19 - 24°C
Winter - 18 - 22°C
The New Zealand standard (NZS 4303:1990) requires that between 8 and 18 Litres of fresh air to be provided per person per second in a commercial facility. As a rule of thumb, 10 Litres per person per second is quite adequate for most situations, including offices.
So when assessing your own workstation comfort be aware of the following:
- The room temperature is within the recommended range.
- Ceiling Air Conditioning vents not directing drafts directly on your back.
- The air does not feel stuffy or lacking of fresh air.