Lighting in Design Q2 2019

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 illumina- tion parameter light colour. In this regard a render- ing 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 characterisation of illuminants and light sources, the light colour of fluorescent lamps is compared to the light colour and illuminance of light bulbs. This leads to the fol- lowing classification of light colours: 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 com-

fort is directly compromised by light sources with a very high illuminance in the visual field, lighting experts refer to glare as a parameter of illumina- tion. Reflection is the second phenomenon that negatively influences the lighting quality. Daylight and artificial light The combination of different light sources contrib- utes 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 suit- able 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 work places dimmable lights can also be advantageous. Source: www.lightingdeluxe.com

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LiD Q2 - 2019