| Space Type | Rp (CFM/person) | Ra (CFM/ft²) |
|---|---|---|
| Office — Open Plan | 5 | 0.06 |
| Office — Private | 5 | 0.06 |
| Conference Room | 5 | 0.06 |
| Classroom (K–12) | 10 | 0.12 |
| Classroom (College) | 7.5 | 0.06 |
| Lobby / Reception | 7.5 | 0.06 |
| Break Room | 5 | 0.06 |
| Restaurant — Dining | 7.5 | 0.18 |
| Retail Store | 7.5 | 0.12 |
| Gym / Fitness | 10 | 0.18 |
| Hotel Room | 5 | 0.06 |
This ventilation calculator applies the simplified single-zone procedure of ASHRAE 62.1-2019 to find the outdoor air a space requires. Choose a space type to auto-fill the people rate (Rp) and area rate (Ra), enter floor area, occupancy, and the zone air distribution effectiveness (Ez), and the tool returns the breathing-zone outdoor airflow (Vbz) and the zone outdoor airflow required at the supply (Voz).
It also reports outdoor air per person and per square foot so you can benchmark a design against typical values. This single-zone method sizes one zone; combining zones into a system intake uses the multiple-zone procedure and the system ventilation efficiency Ev.
| Breathing zone OA | Vbz = Rp · Pz + Ra · Az |
| Zone OA required | Voz = Vbz ÷ Ez |
| People component | Rp · Pz (CFM/person × people) |
| Area component | Ra · Az (CFM/ft² × ft²) |
This follows ASHRAE 62.1-2019 §6.2.2. Rp and Ra are taken from Table 6.2.2.1 by space type; Pz is the zone population and Az is the zone floor area. The zone air distribution effectiveness Ez (Table 6.2.2.2) reflects how well supply air reaches the breathing zone — 1.0 for ceiling supply and return in cooling, up to 1.2 for floor displacement, down to 0.8 for less effective arrangements.