Light for good visibility

Workplace lighting is essential to the visual process and the prevention of accidents caused by poor visibility, while excessive strain on the eyes is to be avoided. Insufficient light levels, glare, or uneven illumination may, for example, cause mental strain, visual fatigue, a deterioration in performance, and a higher risk of errors and/or accidents. Good illumination accordingly helps to promote activity and well-being among staff members, which has positive impacts on their performance and commitment.

The occupational safety and health requirements regarding the lighting of workplaces primarily relate to aspects of visual performance and the avoidance of visual discomfort and visual fatigue. The protection targets to be achieved with regard to the lighting of working environments are defined in the Workplaces Ordinance (Arbeitsstättenverordnung, ArbStättV), the requirements of which are given concrete form by Technical Rules for Workplaces (Technische Regeln für Arbeitsstätten, ASRs). The ASR A3.4 sets out the requirements placed on the illumination of workplaces with daylight and artificial lighting. ASR A2.3 specifies requirements for the illumination of escape routes and emergency exits.

Bringing light into the darkness of statistics: The article "Power analysis for personal light exposure measurements and interventions" uses the example of a study with shift workers to explain how to determine a suitable sample size in order to obtain meaningful results on the correct lighting of the workplace.

Non-visual light effects

In addition to the above-mentioned visual effects, non-visual effects of light are becoming an increasingly important focus of occupational health and safety, as research has identified direct links between light and health. Non-visual effects refer to the influence of light on physiology, mood, and behavior. Research into non-visual light effects in recent years has identified an increasing number of direct links between light and health. Non-visual effects of light are also closely related to factors affecting mental health in the workplace.

Research into non-visual light effects intensified after the discovery of a previously unknown type of photoreceptor in the human eye at the turn of the millennium. Stimulating these cells with blue-cyan spectral components of light induces an alert and awake state. This activation occurs naturally with daylight but can also be produced by artificial lighting. A solid foundation of knowledge on these effects already exists in basic laboratory research, particularly in connection with the day/night rhythm of humans. BAuA's scientific research focuses on assessing the effects of light in practical application in the workplace. This includes measuring light exposure in workers' everyday lives, particularly in occupational contexts. New forms of work, such as working from home or remotely, different occupational groups (particularly vulnerable groups of employees), and different and flexible working time models, as well as their effects on short- and long-term parameters of attention, health, and well-being, are of particular interest. Intensively discussed is how these new findings can be applied to workplace lighting. Further information can be found in the KAN position paper on the consideration of non-visual effects of lighting in standardization.

The article "Protocol for a prospective, multicentre, cross-sectional cohort study to assess personal light exposure" describes an example of the methodology for the precise and comparable measurement of individual light exposure in field research on non-visual light effects.

Daylight

Natural daylight, with its high intensity and blue spectral components, causes the aforementioned non-visual light effects. It also provides the internal clock with the necessary orientation in relation to the time of day. This enables important bodily functions to adapt to day and night requirements. For instance, light is a strong zeitgeber to adjust core body temperature and release stimulating stress hormones in the morning. Conversely, darkness in the evening and at night allows for the uninhibited production and release of "dark hormones" into the bloodstream, ensuring a regenerative night sleep. These effects are closely linked to potential health effects. It is important to aim for a good supply of daylight in the workplace and to avoid unnecessary exposure to light in the evening and at night. To improve the design of workplace lighting in the future, it is crucial to better understand the interaction between daylight and artificial lighting and their influence on employee safety and health.

The purpose of lightwells is to distribute daylight to adjacent rooms. Workrooms supplied with daylight through light wells receive daylight primarily from the walls of the shaft. In the scientific report "Determination of criteria for lightwells to distribute sufficient daylight into workspaces", proposals were developed for assessing an adequate supply of daylight through lightwells and suitable criteria.