I've had many comments. They have changed their perspective as the rating
authority and are requiring outside air treatment procedures that are
outside of ASHRAE 90.1 section G procedures. Typically design outside air
volume is the same between the baseline and proposed, but if you are using
DCV they now require you to model the baseline with the minimum ASHRAE 62.1
volume. So, if you have greater OA volume in your proposed model, you may
be penalized depending on your DCV method and diversity schedule for
occupants in the area with DCV control.

Here is an example clarification question:

*1. **CLARIFY:* Demand control ventilation was modeled for credit for
RTU1 and RTU2 in the Proposed case as indicated in Table 1.4 of the
Template; however, the outdoor air volume for RTU1 and RTU2 in the Baseline
model was not modeled at the ASHRAE 62.1-2004 minimum rates (1,066 cfm for
each RTU) as determined in EQp1: Minimum IAQ Performance. Appendix G allows
schedule changes for demand control ventilation as approved by the rating
authority (Table G3.1.4(Baseline)). As the rating authority, GBCI requires
that the outside air ventilation rates for the Baseline Case be modeled
using minimum ASHRAE 62.1-2004 rates wherever credit is taken for demand
control ventilation in the Proposed Case. The Proposed case minimum rates at
design conditions must be modeled as designed.

*TECHNICAL ADVICE:* Revise the Baseline model so the minimum outdoor air
volume is modeled at 1,066 cfm for RTU1 and RTU2 in the Baseline model. In
addition, provide revised SV-A reports for RTU1 and RTU2 reflecting the
changes. Further, verify that all systems in both the Baseline and Proposed
case are modeled with zero outside air flow when fans are cycled on to meet
unoccupied setback temperatures unless health or safety regulations mandate
an alternate minimum flow during unoccupied periods (in which case, the
unoccupied outside air rates must be modeled identically in the Baseline and
Proposed Case).

Thomas Serra