Hi All,

I'd like to ask for your advice on the allowable interior lighting power density
by ASHRAE 90.1-2007.

One of our clients is planning to go for LEED CI certification for their new
office in a non-LEED certified base building.

Under LEED EAp2, it is a mandatory requirements for the installed lighting power
to be 10% improvement from allowable LPD by ASHRAE 90.1-2007. In addition to the
general lighting provided at the open plan office areas, the base building
landlord has also provided the down-light at the building perimeters which are
controlled separately from the open office general lighting. The perimeter
lightings are also connected to photo-sensors as well. Those lighting are not
required for general lighting at all. Since it was provided by the base
building, it'll be cost implication to remove all the light fittings as well.

My questions are:
1) whether we can consider those lighting as decorative lighting (as per ASHRAE
90.1-2007) and the space is eligible for the additional lighting power density
allowance. If yes, what value should I use in calculation. OR
2) Can those perimeter downlights can be exempted from the LPD calculation?
3) According to ASHRAE 90.1-2007, the ballast loss have to be included in LPD
calculation. Am I right?

Any advice/suggestion would be greatly appreciated. Many thanks!

Regards,
Grace