30% Increased ventilation issues

I think the best way to tackle this one is to do some energy modeling comparing a case with 30% increased ventilation to one without. You'll typically find a hit with energy performance, which can then be presented to the GSA. They're much more interested in energy, than ventilation, given the stringent energy targets that need to be met. New construction will typically need to hit 30% better than ASHRAE 90.1-2007. With an ERV, you can still get by with a high outside air fraction in the SE US, as long as equipment is properly matched to the load. ASHRAE 62.1-2007 provides some good guidance on conditions to assume for dehumidification calculations.