64|A FONDO wave length of the visible spectrum, is considered to have a maximum CRI (100). What happens is that as its color temperature varies throughout the day, some colors will stand out more than others at different times of the day, depending on the tone of the incident light. Intensity On a summer day 120.000 lux can be measured on the ground, while on a winter day they can reach about 20.000 lux. It is not a small difference but it can barely be noticed by the human eye. However, the eye can notice the differences at low levels of lighting, where small variations are perceived visualy. Directionality Directionality of light is another characteristic of light. On a clear day, the sun acts as a spot of light, creating well defined shadows. On the contrary, on a cloudy day light is very diffuse and shadows disappear. Once we have seen the characteristics of natural light, we can get an idea of how light varies, not only during the day but throughout the year. Artificial Light Now, let us consider the time that we spend in our jobs (offices, workshops, stores, etc.) or in the classrooms where we study. Many of the buildings in which we spend many hours a day have skylights and windows that allow the flow of natural light. Because windows do not have a protection system against glare and in many cases workplaces are badly situated or oriented, the most common solution is to screen the windows to stop the flow of natural light. To be sure, it does not always happen, but frequently the easiest solution is lowering the blinds or closing the curtains to avoid the glare caused by exterior light. This has an important consequence: During all the time we spend in those spaces, with limited natural light, we are under constant lighting conditions: the same level of lighting, the same tone of light, linked to directionality and intensity. Our bodies are not used to these conditions; they are accustomed to exterior light, to sun light, with its complete cycle of action, as mentioned before. Lighting of Interior Spaces Currently, in consideration to energy efficiency, the TBC requires that natural light be taken into account when designing the lighting installation. Keep in mind that natural light can represent up to 30% of the lighting needed. In order to make the best use of it, systems have to be designed to redirect the light from skylights and windows to assure the visual comfort of the occupants of the space. Regulation of the luminous flux When you decide to use natural light as a source of light in the illumination of a space, you should have available the elements to capture, measure and control artificial light in order to adjust it Bexley Academy. Londres. Lutron.