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Ventilation rate, person and area

Ventilation rate, person and area

Ventilation rate, person and area

(OP)
Hello,
1- a 1000sq.ft of office space with 4 occupants needs [(5*4)+(1000*0.06)]= 80 cfm of outdoor air.
2- a 2000sq.ft of office space with 4 occupants needs [(5*4)+(2000*0.06)]= 140 cfm of outdoor air.
both spaces have the same height, same everything except the area.
I think the air in the 1000sq.ft space has more CO2 concentration than the air in the 2000sq.ft space. What do you think?

RE: Ventilation rate, person and area

Yes, but the 2000 sf room has more furniture and potential for off gassing as an example. Ashrae 62 is for all indoor air quality, not just CO2.

knowledge is power

RE: Ventilation rate, person and area

(OP)
I agree but not 100%, even it is not necessary to have more furniture, the subject of the outdoor air is to handle gases like Co, CO2, NO2..etc. not dust, dust could be handled by a filters, for example when you use vacuum to clean your furniture, you don't use outdoor air.

RE: Ventilation rate, person and area

(OP)
also for gases, should it be related to the volume or area, let say 10'x10'x10' will have the same volume of 20'x10'x5' but double area, that mean double outdoor air

RE: Ventilation rate, person and area

co2 measured in closed space is a figure relative to outdoor co2 concentration. it comes only from breathing species like humans.

RE: Ventilation rate, person and area

IMC take area and people into account to account for both off-gassing and CO2.
Are you sure about the number of occupants? 500 ft2 per person? Are they super CEOs or something?

IMC and ASHRAE also prescribes how many ft² per person you have to assume. This is to take into account potential changes, and avoid bad assumptions. Like in your case those may be people with a lot of visitors.

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