Comparisons of UNI11095 2003, CIE88 2004, UNI11095 2011 Tunnel Lighting standards


Here are the Luminance Grids for calculating Lseq. of all three standards:

In all three standards there are 9 rings and 12 (radial) sectors.

The UNI11095 2011 grid weights the upper and lower fractional sections by their reduced area. 

The CIE88 2004 has the "tallest" grid but the uppermost and lowermost areas are not used in the calculation, as they are considered to be outside a normal person's field of view. 

The UNI11095 2003 grid did not take into account the fact that the upper and lower areas are smaller, but it did have a wider aspect ratio.

UNI11095 2011 introduced a maximum curve above the minimum curve, presumably to encourage energy saving as well as luminous uniformity:






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