Can anyone with experience showing compliance with ASHRAE 90.1-2004
section 9.4.5 enlighten me as how the baseline calculation should be done?

The confusion I?m having is with the definition of an illuminated wall or
surface length when applying the 5.0 W/linear foot allowance for building
fa?ades. How is the lineal footage of an illuminated wall determined?

For example, if a 100? wide wall has one exterior lighting fixture on it
at the center, is the entire wall considered to be illuminated and thus
the baseline lighting power allowance is 500W? Or is there some method of
determining the actual portion of the wall that is illuminated?

This came up on a LEED project where I had applied table 9.4.5 as
conservatively as possible and only considered a portion of the wall to be
illuminated at each fixture.

Any help would be greatly appreciated.

Robby Oylear, LEED? AP