Hello, Current project has both hardwired permanent lighting fixtures and table lamps plugged into switched receptacles in the hotel rooms of a highrise. Per ASHRAE table G3.1 section 6: b. States proposed building lighting shall meet 9.1.3 and 9.1.4 which excludes plug lighting as they are not permanent fixtures. d. States to include "all" lighting. Exception to d. states to match the proposed and baseline building if the lighting is not shown in the documents; however, they are in the design documents. Baseline says to use lighting power set equal to the maximum allowed for the corresponding method and category in Section 9.2. Proposed b. and d. seem to be contradictory and assuming the base building matched ASHRAE allowable lighting levels, following b. would unfairly cause the proposed building to perform better than reality. Some information I found on the USGBC website seem to suggest the plug fixtures should be included as non-regulated process loads in both the proposed and base building. Any insight/advice would be greatly appreciated. Thank you

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Marcus Sheffer

LEED Fellow

7group / Energy Opportunities

LEEDuser Expert

4454 thumbs up

Wed, 07/20/2016 - 14:05

Hey Tom, Your first assumption is incorrect. Plug in fixtures are included. 9.1.3/9.1.4 address both hard wired and plug in fixtures. You must include all lighting. Since your plug in fixtures are shown on the drawings (i.e. they have been designed), you can claim savings against the baseline. They baseline in a hotel guest room is clearly spelled out in Table 9.6.1 at 1.1 W/sf. The proposed is as designed since it has all been designed. This gets more difficult in multi-family residential since that is not directly covered by 90.1 but that does not apply to your situation.

Thomas Leary

Executive Vice President

JDB Engineering, Inc.

LEEDuser Basic Member

0 thumbs up

Thu, 07/21/2016 - 20:05

Marcus, I agree with you on how the modeling should be done, baseline equals allowable LPD from ASHRAE while the proposed equals both the hard wired and plug in fixtures as designed. This is the only fair and honest method, no gamesmanship, and this is what I directed our Junior HVAC and Electrical Engineers to do. However, our electrical engineer pointed out to me that Table 3.1.b says to follow 9.1.3 and 9.1.4 which if you follow the definitions used in these sections does exclude plug-in fixtures, see the following definitions from ASHRAE: installed interior lighting power: the power in watts of all permanently installed general, task, and furniture lighting systems and luminaires. permanently installed: equipment that is fixed in place and is not portable or movable. I think this might be why so many suggest to model the plug in fixtures as a process load in both models. My problem with this is that it would unfairly and incorrectly show a savings in the model by artificially inflating the base building model energy use. This assumes the proposed hardwired lighting is still compared to the baseline LPD with the plug load simply added to both baseline and proposed. We currently have it modeled as both you and I agree it should be; I simply want to make sure it is correct so it is not questioned when it is reviewed. Also, is my electrical engineer correct when he says a fixture needs to be modeled based on what the lamp holder is capable of rather than the lamp wattage designed. See ASHRAE 90.1 9.1.4.a: The wattage of incandescent or tungsten-halogen luminaires with medium screw base sockets and not containing permanently installed ballasts shall be the maximum labeled wattage of the luminaire. What happens here is several large spaces with LED fixtures will actually use half the LPD based on the lamps specified but when modeled at 100 watts per fixture exceed the LPD substantially, doesn't seem right to me. The only reason the lamp holder is rated higher is its more cost effective for the manufacturer to use the standard base rather than a custom base. I look forward to your response.

Marcus Sheffer

LEED Fellow

7group / Energy Opportunities

LEEDuser Expert

4454 thumbs up

Thu, 07/21/2016 - 20:46

I see his point. LEED has always required projects to include all of the lighting as lighting, not process. Your approach would be considered conservative based on the definitions so it should not be questioned by the reviewer. Your electrical engineer is correct. It says to model the max wattage of the fixture. This is to prevent backsliding from a lower wattage bulb to a higher wattage bulb over the course of operations. So if you are using screw in LEDs and want to claim the savings associated with them the project needs to develop a plan that ensures that there will not be backsliding. Typically this is in the form of a letter from the owner pledging to use certain wattage bulbs. This should not be hard for a hotel and has been accepted by the reviewers for many projects.

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