We are working on a project with very large warehouses with massive roof-mounted air handling units and relatively low occupancy. A 60,000 sf facility may only have 8 workers for example. Do we need to account for the size of the building in our outdoor air ventilation supply, or if the total outdoor air entering the space is more than the required minimum per person does that suffice? I have no doubt that we are supply more outdoor air than needed for the 8-10 workers, but am concerned if the dilution by the large building size needs to be taken into account.
Thanks,
David Hubka
Director of OperationsTranswestern Sustainability Services
527 thumbs up
August 24, 2011 - 7:35 am
Table 6-1 of ASHRAE 62.1-2007 requires warehouses to be provided with 0.06 CFM of outdoor air per square foot during occupied hours. Project teams must account for both people and area when calculating outdoor air rates.
Julia Weatherby
PresidentWeatherby Design & Co. Engineers
94 thumbs up
August 24, 2011 - 10:10 am
For the EBOM rating system, I believe that for each piece of equipment that you determine is not capable of fully meeting ASHRAE 62.1, you have the alternate option of documenting that you have at least 10 cfm/person. I do not recall anything in the alternate option about accounting for square footage. This makes sense to me, because most existing buildings were designed when ventilation rate charts were based on occupancy for most spaces, and not floor area.