Does anyone know if the GBCI reviewers are currently accepting ECMs
based off of garage carbon monoxide sensors to index garage fans? Or if
this can actually be included in the model with appropriate explanation?

IMC requires constant ventilation for enclosed garages, but allows
CO-based systems to activate the fans. This equates to a substantial
energy savings since most systems like this only operate a few hours in
the morning, evening, and at lunch (other than the minimum 0.05 cfm / sq
ft continuous ventilation required by the IMC).

If we explain the system, and explain our assumptions for the use
schedules that dictate the proposed building fan schedules for the
garage, is this acceptable?

Do they require any backup support/studies for exactly how often the CO
levels will rise above acceptable limits, or is it sufficient to make a
conservative assumption that the garage fans will operate from 7-9am,
11-1pm, and 4-6pm at full load? In my engineering experience, CO-based
systems rarely run, and the circulation fans throughout the garage
(which approximate the continuous 0.05 cfm / sq ft requirements of the
IMC CO-based systems) are what really prevent isolated CO buildup.

Thanks in advance,

James Hansen, PE, LEED AP