In buildings where the design of internal associations or atriums areas means that the space cannot be top-lit and is instead side-lit, the Daylighting criteria can be applied as follows;
Minimum values of average daylight factor:
The internal association or atrium area space will need to achieve an average daylight factor of 3% across a minimum of 80% of the space and either a uniformity ratio of 0.3 or a minimum point daylight factor of 0.9%.
Illuminance requirements:
The internal association or atrium area space will need to achieve a minimum daylight illuminance of at least 90 lux for 2650 hours per year.
