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10-07-2011, 06:14 AM #1Regular Guest
- Join Date
- May 2007
ASHRAE 62-2010 and partial occupancy?
Question from someone out of the industry for a while and don't have a copy of 62-2010 to refer to....what allowances does 62-2010 give for buildings with partial occupancy?
I remember with 62-89 for 3 hours or less you could use half of the outside air, but now I think I was told that you use 3/4 number of people of the full occupancy...and this applies to office, school, church, etc...right or wrong?
10-07-2011, 08:10 AM #2
Purging indoor pollutants requires an air change in 4-5 hours. ASHRAE suggest 7 cfm per occupant for non-smoking space. My take is that the one person in a space requires the space air change rate to purge indoor pollutants.
An example of 10,000 ft.^3 space requires 42 cfm of fresh air. Using the 7 cfm fresh air per person rule suggest that 1-6 occupants will get adequate fresh air. Additional occupants require an additional 7 cfm per occupant.
The fresh air requirement for homes is 7 cfm per design occupants plus 1 cfm per 100 sqft as a minimum.
It is also suggested that fresh air is not required when the space is unoccupied.
CO2 control is able to detect a single occupant in a 1,000 sqft space to activate the minimal .25 ach required to purge the indoor pollutants.
So, even one occupants should require a minimal air change rate to purge pollutants.
I am also curious about the real ASHRAE requirement.
regards TBBear Rules: Keep our home <50% RH summer, controls mites/mold and very comfortable.
Provide 60-100 cfm of fresh air when occupied to purge indoor pollutants and keep window dry during cold weather. T-stat setup/setback +8 hrs. saves energy
Use +Merv 10 air filter. -Don't forget the "Golden Rule"