There is significant scope for organisations to improve efficiency, health and safety and employee satisfaction by applying ergonomics in the working environment. Ergonomically designed workplaces, equipment and jobs aim to modify the environment to meet people’s needs. There are many such needs within the office environment.
The preliminary requirement for office furniture is that it does not expose users to the foreseeable risk of injury. To achieve this, the furniture must comply with the appropriate European or British Standards for structural strength, safety and stability.
The worksurface of a desk should be large enough to accommodate all equipment officeworkersand paperwork in an arrangement acceptable to the user. As different jobs require different equipment, it is not possible to produce a generic ideally sized desk. The shape should fit the anatomy of people - people’s arms move in an arc, for example. In other words, desks that curve around the user allow comfortable access to a larger area. The height of the desk should be suitable for everyone who is required to use the workstation. If the desk is non-adjustable, a height of 720mm can accommodate 90 per cent of the population. However, shorter users would require a footrest to enable them to achieve a satisfactory working posture. A height adjustable desk (from 660mm to 900mm) can accommodate everyone without a footrest.
VDUs and keyboards
As the majority of office tasks today involve the use of a visual display unit (VDU), the depth of the worksurface should be great enough to ensure that the user is not too close to the display screen. This is known as the eye to monitor distance. The optimum eye to monitor distance for a small (15 inch) monitor in the seated position is 600mm. However, users have different preferences and distances between 50mm and 750mm are acceptable.
There should also be an additional space of 100mm in front of the keyboard for users to rest their wrists. For seated work, sufficient clearance between the underside of the worksurface and the floor and between the legs of the worksurface is needed. This allows the user to change position to maintain comfort levels and eases the use of VDU equipment and associated tasks because there is room for thighs, knees, lower legs and feet.
The main requirements for an office seat are that:
Blood circulation to the lower limbs is not restricted
It is easy to change and maintain a variety of postures with little muscular effort
Loading or stress on the spine is minimised
The seat surface has sufficient friction to avoid slipping off
For thermal comfort, fabrics are permeable
Compatibility with the worksurface – especially height and the layout of equipment
Lighting and temperature
Lighting and temperature can also influence workers’ health, comfort and performance. The lighting of an area should ensure that people can function safely, optimise the perception of visual information, maintain an appropriate level of performance and provide acceptable visual comfort. The recommended lighting level for general office work is approximately 500 lux, which is suitable for VDU operation. Other areas of offices, such as walkways, require higher lighting levels. Additional lighting at workstations may be needed which can be provided by individual task lighters.
As well as adequate lighting, problems caused by glare should be minimised.
The suggested temperature for sedentary office work is between 19oC and 23oC with no more than a five degree difference between floor and seated height as this, combined with draughts, can significantly reduce thermal comfort. The air in the office should not be stale or too dry. The relative humidity in an office should be between 40 and 60 percent. Because of individual preferences, it is not always possible to provide a thermal environment that satisfies everyone, even if all are wearing the same clothing and perform the same activity. It is advisable, therefore, that temperatures are maintained to the approval of 90 per cent of the workers.
Keep moving and adopt correct posture
The importance of keeping moving cannot be overstated. In addition advice for office workers and their managers on problems associated with undesirable working postures should concentrate on prevention rather than cure. The current view is that it is much better for people to alternate between sitting and standing postures during their work rather than remain seated. Desks that are adjustable up to 1200mm in height enable users to work whilst standing and this should be encouraged.
Why not consider having meetings standing up at a high desk?
Periodically stretching the whole body and getting up and walking across the office are beneficial. Office jobs should also be designed to discourage workers from carrying out the same tasks all day and instead allow tasks with different mental and physical demands to be alternated.
This article covers some of the basic considerations for an ergonomically designed office.
Please direct any questions to the FIRA Ergonomics Department by emailing email@example.com