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NC-v4 SSc6:Light pollution reduction

Ux parameter in BUG rating

Have you ever had Ux parameter in BUG rating in photometric file for a light fixture? For example B2 - Ux - G2. If yes, how did you proceed to show complaince? 

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Bill Swanson
Sr. Electrical Engineer
Integrated Design Solutions
LEEDuser Expert
516 thumbs up

Wed, 09/22/2021 - 12:47

If you look at the polar candela distribution of the light output it should give you a visual of how much uplight the fixture has.

I have heard that these testing chambers are very sensitive.  And sometimes there is uplight detected from the indirect light bouncing off of the bottom of the chamber.  The person doing the test has to manually zero out the uplight values that are detected from a fixture that couldn't make any uplight.

The Ux might be depicting this manual override.  I've seen this Ux in shoe-box area, canopy as well as wall pack fixtures.  I have not seen any official explanation.  I treat it as U0 based on everything else showing zero uplight.

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