Exterior Lighting control for 24x7 operating building

Under 9.4.1.7 b and c the facade and landscape lighting must be off between midnight and 6 am and the other exterior lighting must be reduced and controlled by a timer or motion sensor during this time as well.

Hi Marcus, if shut-off is mandatory from midnight to 06.00 am, when will facade and landscape (exterior) lighting will be on? Isn't this contradictory to the anticipated intent of exterior lighting? Thank you in advance.

From sunset to midnight it'll be doing it's anticipated intended job. Seems like the standard is moving into the direction that the intent doesn't apply between 12 am-6 am and lights only stay on for lack of automatic control. Note that this applies to facade and landscape, not all exterior lights (walkways, plazas, etc). Those other functions must comply with item c. instead of b.  In the User Manual, the section reads "to turn off the lights during daytime hours and when they are not needed in the evening". So the standard assumes it's not needed between midnight and 6 am, likely because people are asleep? The way out of this is an exception from the AHJ or other exceptions under 9.1 (though they unlikely apply to this type of lighting).  If a state or city wants to highlight, say, their historic city hall building at night, they can do so, since they're the AHJ, and they can amend this rule for code compliance when the adopt the standard. I think it's reasonable to then model exterior lighting as operating throughout the night in both the baseline and proposed case for LEED documentation.