We are working on IT/ITES project with above grade parking floors which are naturally ventilated. As per ASHRAE 62.1 TABLE 6-4 Note C - exhaust is not required if two or more sides comprise walls that are at least 50% open to the outside. But the wall opening % is just 30% instead of 50% as per requirement with no mechanical ventilation planned. So, we are planning to show compliance for our LEED Submittal towards IEQ pr1 - Minimum IAQ Performance through CFD analysis to check whether the exhaust flow rate is 0.75 CFM/ft2.

But in that process, our CFD analysis shows that only 85% of the Hours of the year meet 0.75 CFM/ft2 requirement (With the Daily average wind velocity data 100% of the Day of the year meet 0.75 CFM/ft2 requirement). But being a Parking space with only few hours occupancy can we go ahead with submission showing compliance for the Day.

Kindly clarify.