The light that enters through our eyes is not only for vision. The human circadian system responds to light differently than the visual system. The timing of each biological function in mammals is directed by the main clock located in the Supraquiasmic Nucleus, which is regulated by light. However, until now, only the interaction of light with our visual system has been taken into account when choosing the parameters of indoor lighting sources, including those in the classroom. In the publications about school lighting, the first concern was the common parameters of indoor lighting such as horizontal workplane illuminance, illuminance uniformity, and avoiding reflections on different surfaces. In this chapter, the authors show publications about new findings on the effects of light on people, studies carried out in different countries aimed at improving classroom lighting, current regulations on lighting related to classroom lighting, and new parameters that are being considered, along with those already used for new and better lighting.
Top1. Introduction
Human beings have genetically evolved to perform their activities during the day and rest during the night. The evolution of the human species has occurred under periodic and relatively stable cycles of light and darkness. (Moyano, Mónica, & Roberto, 2020) Many days throughout the year when children and adolescents come to school in the morning, they do so in total or partial darkness. The intensity of natural light entering classrooms through windows varies throughout the day and during the different seasons. Students work for many hours in classrooms with lighting that does not resemble natural light in both composition and intensity. When they leave the schools, they usually spend very little time receiving natural light. This results in students living virtually every day with insufficient light, not receiving the proportion and amount of visible light for which we humans are genetically designed.
Since the invention of electric light more than 150 years ago, lighting specialists have been concerned with the development and improvement of luminaires by taking into account the image forming (IF) effects of the light. Following the discovery about 20 years ago of intrinsically photosensitive retinal ganglion cells (ipRGCs) and their role in the NIF effects of the light, active research is being conducted to develop new luminaires that will improve the quality of life of people, also taking into account this latest finding.
In this chapter we are going to talk about the importance of redesigning the lighting of classrooms in educational centres based on the new scientific discoveries on the NIF effects of the light. The new LED luminaires in which the spectral power distribution (SPD) can be varied open up the possibility of creating new sources of interior lighting. Architects have to take all these factors into account both for the design of new constructions and for the refurbishment of buildings.
Good lighting will create a visual environment that enables people to see, to move about safely and to perform visual tasks efficiently, accurately and safely without causing undue visual fatigue and discomfort. The illumination may be daylight, electric light or combination of both. (ISO 8995-1, 2002)
TopLight is defined as any electromagnetic radiation that can create a visual sensation by directly stimulating the retinal photoreceptors of the visual system. In addition to enabling vision, these photoreceptors also drive biological effects that powerfully regulate human health, performance and well-being. (CIE, 2019) Light is a regulator of our psychology and behavior that have evolved over millennia in which lighting provided reliable information about the time of the day. The advent of electric light has now altered this relationship with the patterns of light exposure by reflecting on personal tastes and social pressures. (Edwards & Torcellini, 2002)