Our building is a warehouse with only a single string of clerestory windows at the peak of a gabled roof. All interior light fixtures are ceiling hung T-8s that are 10-12 feet below the bottom edge of the clerestory. I cannot determine how to execute this calculation, as the fixtures obviously have no direct line of site from the building. By changing the orientation of some of the calculations, this would work there were skylights, but in fact it a vertical clerestory window in the roof, not in the walls of the building. Could we show photos of the interior and sections of the building with as an alternative compliance method for Interior Lighting? Anyone have experience with this type of alternative compliance method?