LIGHTING SPECIAL SCHOOLS


Baseline primary school design – section through classrooms


Façade glazing is 30% of the internal wall where no external obstructions exist


Internal refl ections must be 70/50/20 as a minimum


Roof lights are placed over the corridor openings to maximise the internal daylight


The acoustic baffl es are located away from the window openings


overcast sky, light shelves appear to act as obstructions with daylight factor modelling; light pipes and light wells don’t show a signifi cant benefi t, given their cost; and there is little difference when you compare a north and south facade. All in all, the above analysis does not refl ect real life. With CBDM the direct sun and diffuse components will be dynamic in their intensity and altitude for each facade: north, south, east and west. Therefore, while orientation has always been understood, the analysis and results will now detail the impact of the sunlight and daylight, and inform the designer of the quality and quantity of light within the space. The key measure of CBDM is the


South façade glazing requires a light shelf or light redirecting component


Floor to ceiling height is 3m where no external obstructions exist


The external glazing at 30% is appropriate for a 7.2m deep space


dependent direct and diffuse daylight can now be analysed and used to design the façade and light-directing components. The importance of using a design


process that more accurately simulates the world we experience hardly needs highlighting. However, the benefi ts when you design buildings in this way are quite signifi cant. For example: with an


Baseline secondary school section


Useful Daylight Index (UDI). For the baseline designs we have set a target for each learning space of a UDI of 100- 2,000 lux for 80% of the occupied time during daylight hours. Previously, daylight factors concentrated on minimums and averages, but in moving to a maximum and minimum we are ensuring there is always a level of daylight without having too many occasions where the blinds will be pulled down to combat too high a level of daylight. The UDI measure is very much driving a quality of light within a space.


10


CIBSE Journal December 2012


www.cibsejournal.com


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