Drying-Chamber Fresh-Air / CO2 Buildup
Required fresh-air exchange (cfm) and air changes per hour to hold a target CO2.
Example
You enter
- Containment volume (ft³) 2000
- CO2 generation (cfm of CO2) 0.06
- Target indoor CO2 (ppm) 1000
- Outdoor CO2 (ppm) 400
You get
- Required fresh air 100.0 cfm
- Air changes per hour 3.00 ACH
Details, formula, and sources
From a mass balance against the outdoor concentration. Per ASHRAE 62.1; complements chamber-turnover. IICRC S500 governs the drying plan.
Q_fresh (cfm) = CO2 generation (cfm) x 1e6 / (C_indoor_ppm - C_outdoor_ppm); ACH = Q_fresh x 60 / containment_volume_ft3.
ASHRAE 62.1 ventilation-rate mass-balance basis, by name.
ASHRAE-published; the steady-state mass balance is public. IICRC S500 governs the drying plan.
Estimate. AHJ and licensed professional govern.
Field names used by the API: containment_volume_ft3, co2_generation_cfm, target_indoor_ppm, outdoor_ppm, fresh_air_cfm, ach
- Steady state well-mixed single zone at steady state; CO2 generation entered as cfm of CO2ASHRAE 62.1 mass balance