Hello,

We are working on a core and shell distribution center.  The warehouse space has gas unit heaters and the space is considered semi-heated.  There are separate exhuast fans for ventilation.  For the baseline building model we used system 9 from table G3.1.1A. We received a review comment that we cannot use system 9 because system 9 is only for heated only storage. In a post review call the reviewer further explained that space is not "conditioned" and that ASHRAE 90.1 does not regulate semi-heated spaces. The systems in Table G3.1.1A are only for "conditioned" spaces. The reviewer further explained that for semi-heated spaces the systems need to be modeled the same in the proposed and baseline except for: Building envelope per chapter 4, HVAC efficiency that is better than Chapter 6, lighting power less than chapter 9.  So the issue comes down to 1) fan power for the unit heaters; 2) air supply temperature for the units heaters and 3) fan power for the ventilation fans.  So the reviewer's statement that ASHRAE does not intend to regulate semi-heated spaces is confusing since there are requirements for semi-heated spaces throughout.  The question really seems to be if the HVAC systems 9 and 10 are only intended for spaces that exceed 15 btu/hr/SF.  The reviewer is using Section G2.1.1 that says..."HVAC systems in the baseline bulding design shall be based on usage, number of floors, conditioned floor area, and heating source"...  Since there is no "conditioned" floor area qualifier for Heated Only Storage, I still find this unsatisfying.

1. Can someone tell be definitively that Table G3.1.1A does not apply to semi-heated spaces?

2. If it does not, then how is it determined that the systems are to be modeled identically to the proposed and that the energy is all considered process (with all the exceptions above)?  Table G3.1 #10 does not have an option for a building where a heating system is designed, but does not meet the definition of "conditioned space".