Rating System

LEED BD+C: New Construction, LEED ID+C: Commercial Interiors, LEED BD+C: Core and Shell, LEED BD+C: Schools

Rating System Version

v3 - LEED 2009, v2 - Schools 2007, v2 - LEED 2.2, v2 - LEED 2.0

Inquiry

We would like clarification as to whether EA p2 can be demonstrated and EA credit 1 points achieved based on centrally managed lighting wattage limits. Specifically, we would like to know if the wattage limits set by the DALI (Digital Addressable Lighting Interface) system, which allows maximum wattage limits to be programmed into all fixtures, can be used to show credit compliance. Our project, the fit-out of an office space, would like to utilize these controls in order to provide exceptional energy efficiency, individual occupant control including individual fixture dimming in the open office space, as well as to control these lamps with IR occupancy sensors, photo sensors, and programmable time clocks for additional energy savings. The system also includes facility maintenance reporting of lamp and ballast status and energy usage monitoring and trend logging and could include demand response interface with BMS if desired, though not part of this project. While setting the maximum allowable wattage on the DALI system absolutely limits the amount of wattage able to be drawn by the fixtures and this limit is not something that can be over-ridden by building occupants, it is not clear if computer based controls are allowed by ASHRAE 90.1 or the LEED Rating System. It is standard practice for LEED projects to utilize reduced ballast factors or physical wattage limiters as a means to claim energy efficiency from a fixture. The dimmable DALI system and efficient T-5 linear fluorescent lamps proposed by our project cannot utilize fluorescent ballasts with a reduced ballast factor, but the equivalent energy savings can be seen by capping the fixture wattage when setting up the space\'s lighting controls. The alternative to this approach would be to utilize fewer fixtures and produce more light from each, but then the individual workstation controllability provided by the DALI system is negated because individual fixtures are shared by multiple workstations. We would like verification that it is OK to use the maximum allowable wattage set in the DALI system to compare to the AHSRAE lighting power density. The building owner will provide a signed note stating that the wattage limits will not be altered (and won\'t need to be as the lighting levels are designed to be completely sufficient with the 70% wattage limits proposed). This is consistent with the LEED Core and Shell energy modeling requirements that allow reduced lighting power densities if included in the lease agreement (a written confirmation that these levels will be met). Consistent with ASHRAE and the LEED Reference Guides, we will assume the highest wattage lamps acceptable in the fixtures and follow all other ASHRAE guidelines.