Data Center LPD

i don't see a good fit so I would use space by space method.

You can always exceed the LPD as it is not mandatory. You just pay a penalty for doing so. The total LPD is the LPD and both models must follow the same lighting schedule. So no you can't count half the lights. Which space by space category are you planning to use. Typically this should be active storage which is no longer differentiated from regular storage in 2010. ASHRAE 90.1-2010 Addendum cn adds an allowance for computer rooms equal to 1.71 Watts per square foot. Note that a large portion of the lighting should be modeled off for most of the time due to the
mandatory control requirements; therefore the impact on the predicted lighting energy consumption would be very limited.

Hi Marcus,  Apologize to open this old thread. Just to confirm — when you mention there's a penalty for exceeding the LPD, is that penalty applied based on exceeding the baseline LPD values from ASHRAE 90.1?

Yes. Exceeding the basline values reduces your energy savings.

Hi Marcus ,I have a query which our lighting team has raised for a datacenter following LEED V4 energy update(March 2024). Are occupancy sensors required in all enclosed spaces (e.g., offices, meeting rooms, toilets, corridors,etc.)? Similarly, are daylight sensors mandatory in any glazed areas? Finally, does providing DALI dimming in offices/meeting rooms contribute to EQ Interior Lighting credit or EA Optimize Energy Performance?

Section 8.4.2 requires automatic controls in offices and computer classrooms only. Occupancy sensors are an option. So the baseline should be modeled this way, the Proposed as designed.Section 9.4.1.x outlines the lighting control requirements. Section 9.4.1.4 and 9.4.1.5 contain the daylighting responsive controls required. The short answer is yes daylighting controls are mandated in certain spaces under certain conditions. I would post your question about EQ Interior Lighting in that forum.Dimming can contribute to energy savings under Optimize Energy Performance if it is daylight responsive and not required in the baseline. Manual dimming is difficult to show savings for, automatic dimming is easier as it can be logically scheduled. If you want to claim savings for manual dimming do it as an exceptional calculation and thoroughly back up you claims with studies, etc.  

Hi Marcus, I am a bit confused. Why are they terming "manual switches" as part of automatic control device. Also, if i am only providing manual switches everywhere instead of any occupancy sensors, are we deviating from the lighting control mandate.Finally, I read in a previous thread that even if a project is not following any of the mandatory lighting controls specified under section 9.4.1, it is not deemed to be uncertified. We just need to pay a penalty in form of energy savings. Am I right? 

Which section are you specifically referring to? Manual on is still an automatic control device, it just gets turned on at the switch but turned off automatically. Section 9.4.1.2 simply requires switches in enclosed offices. Other controls may be required in certain spaces and under certain circumstances. You are correct, same with receptacle controls, the baseline needs to include the mandatory controls and the proposed gets modeled as designed. So you should see a "penalty" that reduces lighting or plug load savings.

By manual switches, I understood the switch needs a manual intervention for both ON/OFF.  If both ON/OFF is provided in the hands of the occupant, would that deviate from the mandatory provisions of ASHRAE 90.1 2010?

Yes a manual switch is not considered an automatic control device. Those are two different things, required in different circumstances.