When to use: Use to size minimum outdoor air for a zone with the ASHRAE 62.1 Ventilation Rate Procedure: Vbz = Rp·Pz + Ra·Az, combining a per-person rate (Rp) and a per-area rate (Ra) from the space type. For demand-controlled ventilation (DCV), the steady-state indoor CO₂ at the design per-person airflow is Css = Cout + N·10⁶ / Vp, where N is the per-person CO₂ generation (≈0.0084 cfm sedentary) and Vp is the per-person breathing-zone airflow (Rp). Keep the equilibrium CO₂ near ~1000 ppm (≈ Cout + 700) so DCV ramps outdoor air before occupants notice stuffiness.