Thermal and visual comfort
Our Solar control collection is used to improve thermal and visual comfort in that it provides protection from glare and acts as a sunblind, while also preventing solar radiation being turned into heat.
Our bodies need to be in thermal balance so that we do not feel too hot or too cold. It is easy to believe that only the air temperature has an effect, but there are actually six factors which influence the concept of thermal comfort:
- Air temperature
- Air speed
- Air humidity
- Radiation temperature
- Activity level
Instead of talking about air temperature, we usually use the term "operative temperature", i.e. the perceived temperature. A human may not perceive the temperature in a room to be 22 degrees just because the air temperature in the room is 22 degrees. How hot the objects in the surrounding area are (radiation temperature) has a major effect on the operative temperature. The perceived temperature is basically the average of the air temperature and radiation temperature from surrounding objects, such as windows which is hot (in summer) or cold (in winter).
In the international standard ISO 7730, recommendations are provided for the thermal indoor climate. Among other things, it is stated that the operative temperature for normal office work in winter should be 22 °C ±2 °C. If it is hotter or colder than this, surveys show that work performance is adversely affected.
Involves not being blinded by glare from direct solar radiation or its reflections, but it also involves creating a pleasant climate for the eye by not exposing it to excessively great luminance differences (contrasts) at the same time.
The eye has no trouble handling high light intensity, for example; if we go outside on a summer's day, it only takes a few seconds for our eyes to adjust to the brighter conditions. But on the other hand, the eye has a lot of trouble handling major contrasts at the same time.
To ensure good visual comfort at a place of work, we refer to the rule of thumb which is the 1:3:10 ratio. This means that visual objects (e.g. computers, paper), the surrounding field and the periphery (e.g. windows) should be in a luminance ratio of 1:3:10 to one another.
That is to say, the luminance (light intensity) in the surrounding field of view must not exceed three times the luminance of the visual object. Nor must objects within the periphery (such as a window) exceed ten times the luminance of the visual object. The same rule applies the other way round, too: 10:3:1.