Workplace Lighting: Best Practices for Office Lighting Design
Nowadays, up to 80% of the information is processed visually. This leads to the fact that the choice of illumination has a more and more significant impact on the adequate processing of information. At the workplace, the illumination is mainly a part of ergonomic guidelines. Besides the fact that light does influence the personal well-being and health, it has also a positive impact on the motivation and performance. Lighting at the workplace is based on ergonomic principles and has to meet safety requirements within the meaning of occupational health and safety. What has to be taken in to consideration when it comes to office lighting?
Ergonomics and Lighting in the Workplace
Light has different functions that have to be taken into consideration for comprehensive assessment of a lighting concept in a room. Illumination does not only support the visual perception and therefore the information brokerage, but it is also signified by psychic-emotional and psychic-biological effects.
The visual perception in a room is initially achieved by illumination. Therefore, ceiling fixtures have to be chosen individually according to the room condition. In addition, table lights and floor lamps can intensify the lighting effect. They are also able to zoom in on information processing and mental stimulation at the same time.
The appropriate use of daylight and artificial light can have a strong impact on the psychic-emotional factors of lighting. Other factors that are influenced by light are health and performance. An ergonomically designed lighting can be very supporting and as studies have proofed, a good illumination at the working place has also an impact on motivation.
The German Ordinance for Work with Visual Display Units (BildscharbV) implements the minimum standards in Germany regarding safety and health at computer workstations (EG-Directive 90/270/EWG). Additionally, the workplaces ordinance (ArbStättV) regulates more important issues regarding lighting at the workplace.
For the evaluation of quality of illumination, a variety of parameters is analyzed. The major criteria are lighting level and illuminance, harmonic brightness control, light color, direction of light and restriction of glare and shadiness. Those parameters, influencing visual environment, comfort and performance, are frequently noted in scientific and practical approaches.
Recommendations for the Lighting in the Workplace
The following light-measures are suggested to optimize lighting at the workplace:
(1) Just as any other lighting concept, lighting at the working place should be flexible and energy-saving. An optimal lighting depends on the visual task and requires both a balance of indirect and direct light sources, as well as a balance between daylight and artificial light.
(2) Flexible application, energy saving and ergonomics are requirements that have to be met by modern lighting technologies. A combination of different types of lamps enables an individual illumination in rooms according to the visual tasks. Additionally, manufacturers provide energy-efficient LED bulbs.
(3) One of the most important criterions for lighting at the work place is the respective work- and visual task. This decides on the choice of illuminants.
Lighting Level & Illuminance - Light Color & Direction of Light
The right light level at the workplace avoids tiredness and lack of concentration. This can be regulated by the illuminance which is measured in Lux (lx). A minimum of 500 Lux is stated for the brightness at computer work stations. Generally speaking, an increase in illuminance boosts the visual performance and positively influences the detailed and fast visual information processing. An illuminance between 500 and 1000 Lux can also be seen as stress-free.
The more complex the visual task is, the higher the illuminance requested. Additionally, person variables like the age are crucial for a final and overall evaluation of the chosen lighting concept. An illuminance between 750 and 1.000 Lux is said to sustainably enhance the working performance of elder workers.
Mood lighting is often achieved by the illumination parameter light color. In this regard a rendering index (CRI) is used as orientation. Indices from 90 Ra can be seen as natural values and are used for example in connection with LED lights and fluorescent lamps. For a further characterization of illuminants and light sources, the light color of fluorescent lamps is compared to the light color and illuminance of light bulbs. This leads to the following classification of light colors: warm white, neutral white and bright white.
Also, effects of light and shadows decide on the lighting quality. To achieve a balance between natural and artificial light and to avoid shadows and glare, it is recommendable to place lights parallel to the window and the working place. This coherence was already pointed out by one of the first studies of the Ergonomic Institute (1997). If the visual comfort is directly compromised by light sources with a very high illuminance in the visual field, lighting experts refer to glare as a parameter of illumination. Reflection is the second phenomenon that negatively influences the lighting quality.
Daylight and Artificial Light - Direct and Indirect Lighting
The combination of different light sources contributes to a lighting concept that can be adapted to the different light requirements. The use of direct and indirect lighting in addition to a balanced day- and artificial light, is very important.
On the one hand, in offices and at computer work stations a very high level of indirect lighting is recommended to support non-glaring. On the other hand, direct lighting provides the essential shadiness for a good illumination. That is the reason why combining both illumination techniques is vital.
Also, it is necessary to use appropriate bulbs for right illumination (general lighting), as they support the task lighting in the room. Lights with a movable luminaire head are highly recommended for a suitable lighting at the workplace. When both computer-assisted and other tasks have to be managed from one workplace, individually placed table lamps serve as additional light sources. At some working places dimmable lights can also be advantageous.
Lighting belongs to the major criteria of ergonomics in the workplace. The term ergonomics is derived from the Greek expressions ‘ergon’ (engl. work) and ‘nomos’ (engl. law). This scientific approach aims on designing the respective workplace and working environment to adapt to the needs of every single worker. The following lighting factors have a negative impact on the lighting at a working place and should be avoided. These factors are reflection, glare and shadows. An integrated lighting concept for the work should therefore focus the following points.
Checklist for Work Place Illumination
- Is there sufficient natural light at the workplace?
- Does the selected lighting correspond to the appropriate visual task?
- Is a balance of direct and indirect light guaranteed?
- Is there a need for optimization in the use of energy saving lamps?
- Do you use a flicker- and glare-free lighting?
- If the light intensity in the room individually adjustable?
- Do you use pleasant and bright light colors (warm white, neutral white)?
- Do you avoid glare and distracting reflections?