Explanation on UGR19 [CAT2] & All the different criteria set against the different applications [Nova Panelite]Brillianz Electronic Systems has Brillianz Electronic Systems has a passion to help anyone understand further lighting terminology. With this in mind please find the explanation on UGR19 [CAT2] and all the criteria set against the different applications [Nova PaneLite]...
luminaires or windows. Discomfort glare is quantified by the Unified Glare Rating (UGR). Glare
calculations are complex and involve summing all the light from all sources at a particular angle
entering the eye at a particular location. The UGR simplifies this by providing a rating for a luminaire
which enables us to determine if it is likely to cause discomfort in specific types of work situation. In
offices used for normal (clerical) type work, the LUX level will be around 500 and at this lighting
intensity a UGR of 19 is specified as the maximum glare rating above which discomfort may occur.
Glare is subjective and sensitive to many factors including positioning of workspaces and relative
positioning of luminaires. In a small (4m x4m) office glare is unlikely to be noticed even if the luminaires
are > UGR19, as the visual angle from the eye to the luminaire will be well above the normal sight line
for working and no discomfort is likely to arise. This will not be so in a shared workspace (say 15m
x15m) where distant luminaires could easily cause discomfort in the working sight line or by reflectance
from a Computer screen. Here luminaires with UGR 19 or better ensure that in most situations, stray
light cannot enter the sight line and cause discomfort.
UGR19 (in old terms CAT2 lighting) limits the emission of light at shallow angles from the luminaire
which might otherwise interfere with office tasks.
In corridors and circulation spaces, where people are standing and the typical LUX levels are closer to
200, a UGR of 22 is acceptable.