I am working on a project, 6-story residential building in an ovesea U.S. military base.
At first, for the baseline, I used system-1, because in ASHRAE, it is stated that residential spaces in buildings are used primarily for living and sleeping. They include, but are not limited to, dwelling units, hotel/motel guest rooms, dormitories, nursing homes, patient rooms in hospitals, lodging houses, fraternity/sorority houses, hostels, prisons and fire stations.
However, this mech. engineer, who is a Mech. P.E., argued that the project shouldn't be considered as a residential, because in u.s. military projects, and U.S. building codes, consider residential building of 5 or more stories as a commercial building.
I am not an energy-modeller, nor I have a MEP experience. I am just managing the project, and responsible for preparing an energy plan. Because of my inexperience with MEP codes, I couldn't argue with him, and my co-workers changed the baseline hvac system to system 7.
If anyone can answer this question, I would greatly appreciate
and if you have any documentation that supports your answer, that would be great!!!
thank you
Sparky-
I have been involved in a military residential building in the U.S. that was 5 stories. I am 100% certain that the project was modeled as residential (and passed using such). There is no literature to cite other than 90.1-2007 appendix G Table G3.1.1.A
The classification of the baseline building in 90.1 says nothing about local codes and should not be considered (for selection of the fictitious baseline building)
While the actual building may be subject to local codes, the baseline building should be modeled as residential. This will only help the total number of LEED points.
SO, the actual building may require system 7 or better, but GBCI reviewers are going to request that you model the baseline per system 1 (I have also seen military projects of 5 stories get flagged for not being modeled as residential).
In my experience, there seems to always be confusion. But you were correct the first time. The fact of the matter is that if you meet the criteria of 90.1 (over 3 story residential) and Appendix G3.1.1.a for a baseline building being primarily residential and all other spaces that do not fit the definition in the notes of Table G3.1.1.A provided that they sum up to over 20,000sf, then yes you may be in a 'Mixed Use" building, but still primarily a residential not commercial building. You would need to apply the correct baseline wall performance values to each different construction in this case.
Some people not familar with ASHRAE may misconstrue 90.1 being commercial and 90.2 being only residential...ASHRAE in their infinite wisdom has already provided you with High Rise Residential. Look to the 90.1 definitions for your answers, and stand on them. Especially the Def for low-rise residential buildings and the scope of 90.1.
Best of luck to you. And if you are following ASHRAE 90.1, then I am assuming someone already chose this path, after looking at the International Energy Code. They give you the option to use ASHRAE. LEED does not.
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