Hello all,

Regarding light leaking from a high bay warehouse with clerestory windows above the dock doors. The situation is as follows:

1) T5 High Bay Lighting installed at the roof deck at approximately 37' off finished floor.
2) Center of clerestory 4X4 window at approximately 25' off finished floor (29' off exterior grade).
3) T5 Lighting is "shielded" by the walls above the clerestory windows (12' +/- delta in height).
4) Hours of operation will exceed the 11:00 PM limit and all lights will be used for operations during the after hour period.
5) Blinds are not an option.
6) Dimming is not an option.
7) Shielding is our only option and this is created by the delta in height noted above.

So, given these parameters, here are the questions at hand:

1) LEED specifies "direct line of sight to any non-emergency luminaires must have shielding." What area do we use to establish a direct line of site? Anywhere in the defined site? Outside the site?
2) Do they consider line of site horizontal or at any angle that allows one to look into the window?
3) If someone is standing is standing outside of the building and can see a light fixture inside, does that automatically disqualify?
4) If question three doesn't automatically disqualify, then how and where do we measure the percentage of light coming out of the windows, i.e. do we use a light meter in a vertical position while standing in a lift bucket? if so, how far away from the window and at what height?
5) How can we calculate and/or measure the amount of light escaping through the windows?

Please forgive my dissertation. I believe this credit was designed more for more of a curtain wall or storefront glass assembly so our warehouse scenario is not in the norm and as always, each project if different.

I have sent this question in to GBCI and hope to hear something soon (yeah right).

Thank you in advance for any feedback.