Parking Garages Abutting Conditioned Space

While we are on the topic of parking garages, I have had projects where a parking garage abutted a conditioned building. Reviewers have treated them differently. During the review of one project, GBCI reviewers obsessed about the potential for heat transfer from the building to the garage. The reviewer said, “The reviewer has seen several similar situations where the project team has modeled the adjoining facade as adiabatic walls. This is inappropriate. Because the Parking Garage is open to ambient conditions, the adjoining building’s walls should be modeled as exterior walls like the rest of the facade.” In our case, the reviewer’s concern was unwarranted. The garage and the building were completely isolated from one another, with a 3” expansion joint at all slab connections, and the adjoining wall WAS modeled and built as an exterior wall. On another project, the garage included conditioned elevator lobbies at each floor with no break in the slab between interior and exterior. Insulation was applied the underside of the slab, but the slabs & beams themselves ran continuously through the adjoining wall. Somehow, this raised no concern for the reviewers, but I was never sure that we had modeled heat transfer correctly where the slab passed from indoors to outdoors. This is a common condition, how should it be modeled?