No special window frame was applied for these measurements, other than explained in the variants below, see table 2. The reference opening was not covered with a glass plane; this facilitated the experimental set-up and would still give interreflection problems when a coloured glass or translucent glass plane was inserted. When the transition zone consists is situated in or directly on the glass, only absorption and diffraction are possible methods to reduce the luminance ratios. Diffraction is not so suitable as it has the same absorptive effect for a direct view through the window, and the diffracted rays next to the left and right side of the window can be very irritating. Diffraction is in general used for highly positioned windows where the diffracted rays give extra light deeper into the office room.

Position Method

transition zone : absorption on or in the glass plane

Realisation empty coloured glass

patterns in transparent glass (dots, stripes, etc.)

reflection diffraction reflection

X X

not possible same effect as absorption lamellas

transition zone in front of the window opening

translucent glass

b

SHAPE * MERGEFORMAT