Manual Lighting Desing

MOHAMED BOUBEKRI

Lighting Design

Background and significance of daylighting
The presence of daylight in educational buildings plays a significant role in the process of learning. Performance of students is measured by a number of yardsticks, among them are students' performance on tests and level of absenteeism. In the five years between 2000 and 2007, more than 1,000 schools will be builteach year in order to meet the demand of students in kindergarten and elementary schools in the United States. With calls for energy conservation, improving the health of children and the quality of the educational settings of kindergartens and schools, some major studies using rigorous scientific methods were undertaken to assess the impact of daylight on the well-being and the scholasticachievements of pupils at all levels. One of such major studies' analysed test scores of more than 21 ,000 students in three school districts in three different US states, namely California, Colorado and Washington. The following results were obtained:

• Students in classrooms with the most daylight progressed 20% faster on math tests and 26% faster in reading tests • Classrooms with the most windowarea were associated with a 15-23% faster rate of improvement • Classrooms with skylights were associated with a 19-20% faster rate of improvement • Classrooms with operable windows were associated with a 7-8% faster improvement in three out of four cases that have been investigated when compared to classrooms with non-operable windows

Students who attend daylight schools seem to perform up to14% better than those who do not according to another major survey of 1,200 elementary students in North Carolina. The authors of the study did not provide daylight illuminance levels but they characterised the conditions of the daylight schools as 'average illumination levels in the skylit classrooms are two or three times higher than in classrooms with electric lighting in peak conditions.'There seems to be a direct correlation between the presence or lack of daylight and the way pupils perform. But why do students perform better with daylight?

Daylight and circadian rhythm One of the most obvious relationships between humans and daylight is that of the circadian rhythm, i.e. the cycle of day and night and the complex chemical and physiological variations that control our bodies 24hours a day. The timing and functions related to these processes depend on our biological clock. Arguably the most influential factor in this timing is the presence of daylight. 2 This rhythm directs the body to release hormones and trigger functions that control our days. Researchers found that from ten o'clock until noon our immediate memory is at its best. and is therefore a positive factor inschoolwork, concentration and debate; whereas the hours from six in the evening to midnight are favourable for studying since then our long term memory is at its best. This circadian rhythm is especially important in children since their systems seem to be more sensitive to change and variation. The presence of daylight in classrooms is crucial to the preservation of this rhythm and the body'snatural clock.

Seasonal Affective Disorder and depression One possible effect of lack of daylight or lack of the presence of daylight is Seasonal Affective Disorder. Depression, fatigue, irritability and lack of concentration are just a few of the many symptoms that SAD sufferers usually confront. Similar symptoms were found in children confined to windowless classrooms for entire school days.Children exhibited restlessness and much more irritability in these classrooms. Concordantly, children in classrooms with sufficient daylight were able to develop concentration skills with more ease. A by-product of SAD and its symptoms are frequent absences and a lack of resistance towards diseases. Although many of the studies related to SAD have been performed on hospital patients and people in...