Technical information
www.fagerhult.com • www.fagerhult.co.uk508
Energy Directive 2002/91/EC
The LENI number, the rating index for lighting’s specific annual energy usage
Availability of daylight
Daylight must be included within the calculations to give a correct
value. The availability of daylight divides the room into dierent
zones. The dierent zones describe a specific daylight interval,
divided by a daylight factor: Strong, Medium, Weak or None.
Luminaires located in the stronger zone can utilise a larger devalua-
tion of the utilisation, which reduces the total power consumption.
The daylight factor is obtained by making a light measurement of
indoor illuminance and expressing the measurement result as a
relation to the outdoor illuminance at the same time.
The formula becomes D(%) = E
indoors
x 100 / E
outdoors
1%>D2%>D≥1%3%>D≥2%D ≥ 3%
Strong Medium Weak None
The room contains zones with dierent daylight
intervals. The availability of daylight is dependent on
the room's glazed area and window placement. In this
room there are potential savings of over 60 % with the
use of daylight and absence control.
For more information go to www.barbourproductsearch.info