| Space Type (Table 6-1 row) | Rp (CFM/person) | Ra (CFM/ft²) |
|---|---|---|
| Office space | 5 | 0.06 |
| Reception areas / main entry lobbies (office) | 5 | 0.06 |
| Conference / meeting | 5 | 0.06 |
| Classrooms (ages 5–8 and age 9 plus) | 10 | 0.12 |
| Lecture classroom | 7.5 | 0.06 |
| Hotel lobbies / prefunction | 7.5 | 0.06 |
| Corridors | — | 0.06 |
| Breakrooms (office buildings) | 5 | 0.12 |
| Restaurant dining rooms | 7.5 | 0.18 |
| Retail sales | 7.5 | 0.12 |
| Gym, sports arena (play area) | 20 | 0.18 |
| Health club — aerobics room / weight room | 20 | 0.06 |
| Hotel bedroom / living room | 5 | 0.06 |
| Computer (not printing) | 5 | 0.06 |
| Science / university laboratories | 10 | 0.18 |
Rates are for standard air (0.075 lb/ft³). Table 6-1 also lists a default occupant density for each row — use it for Pz when the design occupancy is not known. Healthcare spaces (patient, exam, and operating rooms) are typically designed to ASHRAE 170, which has no rows in this table.
Doing this for a whole building? See this step inside a connected AIM Works project — loads, ventilation, equipment, and Design Review in one place.
Book a Demo →This ventilation calculator applies the zone calculations of the ASHRAE 62.1-2019 Ventilation Rate Procedure to find the outdoor air a space requires. Choose a space type to auto-fill the Table 6-1 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 the zone calculations of ASHRAE 62.1-2019 §6.2.2. Rp and Ra come from Table 6-1 (Table 6.2.2.1 in the 2016 edition) by space type; Pz is the zone population and Az is the zone floor area. The zone air distribution effectiveness Ez (§6.2.2.2) reflects how well supply air reaches the breathing zone: 1.0 for ceiling supply of cool air, 1.2 only for displacement or low-velocity underfloor supply, 0.8 for ceiling supply of warm air 15 °F or more above space with a ceiling return, and 0.7 for floor supply of warm air with a ceiling return. Warm ceiling supply less than 15 °F above space with a ceiling return is 1.0 only if the 150 fpm jet reaches within 4.5 ft of the floor; otherwise use 0.8. For a single-zone system the outdoor air intake equals Voz; multiple-zone recirculating systems also need the system ventilation efficiency Ev, which this tool does not compute.