Building Facade lighting - ASHRAE Baseline values

I am confused by that too. Not sure of the logic behind the linear option. It is our understanding that you can select either option for any facade lighting system. So select the one which results in the higher allowance.

I would assume that the linear option would be measured in alignment with the light fixtures. So if they are horizontal you measure horizontal, if they are vertical you measure vertical. This is just my guess. Anyone know more than I about the linear option?

We are also struggling to understand this lineer option of 90.1-2007. We have a facade that is illuminated by horizontal LED luminaires (RGB) at each window frame. This is repeated for each floor. Then, we have continous vertical LED strips, RGB again, illuminating non-transparent vertical strips on the facade. And for the spire, we have the vertical LEDs continuing and additionally three strips of LED fixtures on three sides of portions of s/s mesh that forms the spire. Using the area method for calculationg the total exterior lighting allowance does not work, produces very low total allowances for the whole facade. We need to use the length of the horizontal component of the illuminated windows and the length of the vertical strips and the area of the spire mesh to calculate the total allowance in order to obtain results comparable to what the lighting designer is planning. Question is, has any clarification on the use of the lineer option been developed by the USGBC or ASHRAE that may be of use to validate our method of calculation towards the LEED Reviewer?

I am not aware of any clarification on this issue. I checked the ASHRAE 90.1-2007 User's Manual and it does not address this issue in any detail.