Whilst each environment and office space will be different, there are certain guidelines from The European Directive on Working with Computers and Safety Legislation which calls for an office working environment to be ergonomically modified to best serve each individual’s specific needs.
Office furniture in the UK is tested and certified to either British or European standards which satisfies the requirement for the furniture to be safe and stable and not expose the user to possible risk of injury.
The workspace needs to be the best available space when taking into account the following requirements: The workspace needs to accommodate all equipment and paperwork required for the user to do their specific job properly. The workspace also needs to fit the anatomy of the user and the tasks they need to perform. The workspace needs to do both of these things as well as take into account the other users’ workspaces that may be adjacent or around it in the whole office space. Workspaces can be all shapes and sizes depending on the above factors.
With most office desks being around 720mm from the floor to the top of the desk and having a usual desktop thickness of 25mm – this leaves 695mm from the floor to the under side of the desktop. 650mm is usually considered the minimum height to the underside of the desk and can only be achieved using a height adjustable desk at its lowest setting.
Clearance along length
600mm is considered to be the absolute minimum width of legroom beneath a desk. 1000mm would be the ideal minimum to allow some movement space for the users legs.
Most office desks with have a standard height of around 720mm from the floor to the desktop, this is judged to accommodate around 90% of the population. A height adjustable desk will usually have a range from around 650mm up to 1200mm – this type of desk can be used for wheel chair users or tall users. A height adjustable desk is also beneficial for users with bad backs and users that have a job that benefits a change in working position from sitting to standing on a regular basis. Users that are shorter will benefit from a footrest under a normal height desk to achieve a standard working position.
The main criteria for the depth of an office desk, is to ensure that the user is not too close to the computer monitor. Most computer monitors are now the thin TFT or LCD style which can be situated on or mounted to the desk in varying ways. (See the Monitor Height Section Below!) As these types of monitors are in their nature thinner than the old style CRT monitors it gives greater scope for designers to produce desk depths from 600mm which is classed as narrow to 800mm or 900mm in depth.
The basic rule of thumb should be that from the user side of the desk there should be approximately 100mm of clear desk before the keyboard for the user’s wrists to rest on whilst using the keyboard. A keyboard is usually about 150mm in depth leaving 350mm depth to the back of a 600mm deep desk or 550mm on a more standard 800mm deep office desk for the monitor.
Each user will have different requirements for the height of their computer monitor, although it is generally recognized that the top of the monitor should be aligned horizontally with the users vision unless altered for a specific task or adjusted to avoid glare from light.
In order to get the correct adjustability as described above, it is usually necessary for the monitor to be mounted on an articulated monitor arm.
The monitor arm can be mounted to the edge of the office desk or through a cable port via a clamp or bolted directly through the desktop. (Not really recommended as this will damage the desk!) Another style of monitor arm can be mounted to a free-standing or desk mounted screen, although the screens will need to have two toolbars in order for the bracket to attach.
In some countries, legislation limits laptop use to as little as two hours, although there is no such legislation in the UK. It is always a good idea to adjust posture and not stay in the same working position for any length of time – especially when using a laptop. Taking on board the same theories for making a normal TFT monitor work in an ergonomic fashion, if a laptop is placed on a stand and used in conjunction with a separate keyboard and mouse, it enables the laptop user to achieve a better viewing distance and working posture thereby avoiding fatigue in the arms, hands, neck and eyes.