Hi

I am again and again confused by the definitions in ASHRAE 90.1 of semi-heated and conditioned, particularly in connection to our typical projects. We have climate zone 4 or 5 and usually have well insulated building envelopes. This results in an installed heating power in an office space of 25-40 W/m², which is below the threshold of 45 W/m² in Table 3.1. As the office zones are cooled with more than 15 W/m², they are still considered conditioned, correct?

How do we deal with all the intermediate areas, such as restrooms, storage, circulation, stairways etc? Some don't have heating and most if not all are not cooled. That would mean semi-heated or even unconditioned. However, they are mostly surrounded by conditioned zones and are therefore "indirectly conditioned". However, these intermediate zones are often clustered together, limiting the surface area between an individual zone and the adjacent conditioned zone, so this also doesn't apply to most.

Is it ok to sort these intermediate zones into the conditioned zone category? I can adapt my setpoints to appropriate values (ex. 18 °C for heating, 50 °C for cooling, same in baseline). It makes the baseline model so much easier to construct, and I see it as the more conservative approach. Furthermore, it makes more sense, as these zones are typically not insulated towards the conditioned office area and therefore actually indirectly conditioned. Also, ventilation to these zones is through the same AHU that provides the adjacent office space.

Thanks!

Sarah