Daylight factors and ADF%
The average levels of daylighting within rooms can be assessed in LUA. ADFs are expressed a % ratio of average illuminance falling on the workplane divided by the unobstructed external illuminance.
Best practice minimum % levels have been set within BS 8206-2: Code of Practice for general daylighting are:
– 5% for a well daylit space
– 2% for a partial daylit space
If the % falls below 2% it is likely that artificial lighting will be required.
BS 8206-2 also defines the % minimum levels for housing:
– 2% for kitchens
– 1.5% for living rooms
– 1% for bedrooms
Levels of over 6% may be an indicator for overheating/heat loss problems.