Hi all,

I am puzzled with the interpretation of Ashrae 90.1-2007 G3.1.1 where is
says each floor shall be modeled with a separate HVAC system.

My proposed building is a 4 story office building with 3 floors office and
a first floor consisted of cafeteria, kitchen and gym. Office floors have
one system per floor and the first floor has three systems for each
specific area. My baseline is using system 6 for the typical office floors.
I am trying to interpret the G3.1.1 for the first floor. If I combine all
those areas into one system their occupancy schedules, HVAC schedules, OA
rates etc are all different and if I use one system, the schedules will not
match the proposed. The kitchen qualifies for exception b due to thermal
loads, so I will use a single zone system for that area. I am wondering how
I should approach the gym and cafeteria. Can I use two systems in the
baseline for those areas? They do not fall into exception b since their
schedules and loads do not differ significantly from other spaces (office
spaces) but they do differ from each other and using one system for those
two different usage areas brings the dilemma of using a different schedule
from the proposed building.

Any insights will be greatly appreciated.

Regards,
Beran