Properties
The main goal of lighting design is to provide the right visual conditions for the users of a room at a given time and place to take care of their comfort and well-being.
Properties describing lighting:
- Natężenie – miara ilości światła padającego na powierzchnię. Intensity – a measure of the amount of light falling on a surface. The unit of measurement is lux[lx];
- Luminance – a measure of the amount of light in a given direction. It is measurable and expresses how much light reaches the observer’s eyes. The unit of measurement is candela per square meter [cd/m2];
- Hue – a measure defined by the color temperature of light. The unit for determining color is Kelvin [K];
- Warm light – with a temperature of 2700K, suitable for relaxation;
- Neutral light – with a temperature of 3200-4200K, appropriate for multifunctional rooms where we spend a lot of time;
- Cold light – with a temperature of 5200K, stimulates the secretion of serotonin, supports concentration, ideal for office spaces;
- Luminous flux – a measure of the amount of light. Determines how many lumens there are per square meter. The unit of measurement is lumen [lm].
Impact on health
The proper adjustment of lighting has a significant impact on the daily functioning of man and the course of his body’s physiological processes. This relationship is strongly linked to the history of the origin and development of the human species, which adjusted the course of its day according to the position of the sun.
Each of us functions according to our own circadian rhythm, which is strongly dependent on light. Its excess in the evening can lead to a disruption in the secretion of melatonin, which affects the body’s need for sleep. The consequence of abnormal secretion of the hormone leads to agitation and problems with falling asleep.
Nowadays, many rules and lighting standards have been developed to suit the activities we perform. For proper concentration and increased efficiency at work, it is worthwhile to get other sources of light than those that support relaxation and put us in a comfortable mood.
HCL approach – the right light at the right time
The lifestyle of modern people requires them to depart from the natural rhythm of day and night, which is determined by the positions of the sun. Artificial lighting was therefore necessary to extend the time of day and provide people with round-the-clock activity. It is for this reason that lighting concepts should focus on humans and support their functioning during the day. The HCL (Human Centric Lightning) approach deals with the development of lighting standards that stimulate the natural flow of the day, with long-term effects on health and well-being. The design of these relationships is based on the visual, emotional and biological effects of light on human functioning.
The diagrams below show the assumption of the HCL approach compared to the natural light pattern depending on the season.
During the summer, it can be seen that the artificial light graph follows natural daylight.
In contrast, in winter, when the sun sets much faster than in summer, the HCL approach extends the day.
Standards
Each member country of the European Union is obliged to implement the assumptions of the standard “EN12464-1:2011”, which takes into account recommendations for lighting conditions in workplaces. Each country also has the opportunity (taking into account the objectives of the EU) to develop its own guidelines. The design of lighting in workplaces is quite a challenge, as there are many dependencies that need to be taken into account, including: the number of people in the room, age, activities performed, the number of hours spent in the room, time of day.
In terms of illuminance, a pair of standards can be distinguished according to European Union conventions:
|
Type of room |
Illumination intensity [lx] |
|
Office room for desk work |
500 |
|
Reception |
300 |
|
Entrance halls to public use buildings |
100 |
|
Conference rooms |
500 |
|
Classrooms in public schools |
300 |
|
Treatment rooms in medical facilities |
1000 |
