Air Change Rates in typical Rooms and Buildings
Fresh air (make up air) rquirements - or recommended air change rates (ACH) for typical rooms and buildings like auditoriums, kitchens, churches and more.
The volume of fresh air (make up air) required for a proper ventilation of a space is determined of the size and the use of the space - typical the no. of persons in the space, if smoking is allowed or not and pollution from processes.
The table below indicates air change rates (air changes per hour) commonly used in different types of rooms and buildings.
- Note! - be aware that it may be necessary to calculate required supply air based on no. of persons in the room or building. More information about required supply air per person can be found here.
| Building / Room | Air Change Rate - n - (1/h) |
|---|---|
| All spaces in general | min 4 |
| Assembly halls | 4 - 6 |
| Attic spaces for cooling | 12 - 15 |
| Auditoriums | 8 - 15 |
| Bakeries | 20 - 30 |
| Banks | 4 - 10 |
| Barber Shops | 6 - 10 |
| Bars | 20 - 30 |
| Beauty Shops | 6 - 10 |
| Boiler rooms | 15 - 20 |
| Bowling Alleys | 10 - 15 |
| Cafeterias | 12 - 15 |
| Churches | 8 - 15 |
| Classrooms | 6 - 20 |
| Club rooms | 12 |
| Clubhouses | 20 - 30 |
| Cocktail Lounges | 20 - 30 |
| Computer Rooms | 15 - 20 |
| Court Houses | 4 - 10 |
| Dance halls | 6 - 9 |
| Dental Centers | 8 - 12 |
| Department Stores | 6 - 10 |
| Dining Halls | 12 -15 |
| Dining rooms (restaurants) | 12 |
| Dress Shops | 6 - 10 |
| Drug Shops | 6 - 10 |
| Engine rooms | 4 - 6 |
| Factory buildings, ordinary | 2 - 4 |
| Factory buildings, with fumes or moisture | 10 - 15 |
| Fire Stations | 4 - 10 |
| Foundries | 15 - 20 |
| Galvanizing plants | 20 - 30 |
| Garages repair | 20 - 30 |
| Garages storage | 4 - 6 |
| Homes, night cooling | 10 - 18 |
| Hospital rooms | 4 - 6 |
| Jewelry shops | 6 - 10 |
| Kitchens | 15 - 60 |
| Laundries | 10 - 15 |
| Libraries, public | 4 |
| Lunch Rooms | 12 -15 |
| Luncheonettes | 12 -15 |
| Nightclubs | 20 - 30 |
| Machine shops | 6 - 12 |
| Malls | 6 - 10 |
| Medical Centers | 8 - 12 |
| Medical Clinics | 8 - 12 |
| Medical Offices | 8 - 12 |
| Mills, paper | 15 - 20 |
| Mills, textile general buildings | 4 |
| Mills, textile dye houses | 15 - 20 |
| Municipal Buildings | 4 - 10 |
| Museums | 12 -15 |
| Offices, public | 3 |
| Offices, private | 4 |
| Paint shops | 10 - 15 |
| Paper mills | 15 - 20 |
| Photo dark rooms | 10 - 15 |
| Pig houses | 6 - 10 |
| Police Stations | 4 - 10 |
| Post Offices | 4 - 10 |
| Poultry houses | 6 - 10 |
| Precision Manufacturing | 10 - 50 |
| Pump rooms | 5 |
| Railroad shops | 4 |
| Residences | 1 - 2 |
| Restaurants | 8 - 12 |
| Retail | 6 - 10 |
| School Classrooms | 4 - 12 |
| Shoe Shops | 6 - 10 |
| Shopping Centers | 6 - 10 |
| Shops, machine | 5 |
| Shops, paint | 15 - 20 |
| Shops, woodworking | 5 |
| Substation, electric | 5 - 10 |
| Supermarkets | 4 - 10 |
| Swimming pools | 20 - 30 |
| Textile mills | 4 |
| Textile mills dye houses | 15 - 20 |
| Town Halls | 4 - 10 |
| Taverns | 20 - 30 |
| Theaters | 8 - 15 |
| Transformer rooms | 10 - 30 |
| Turbine rooms, electric | 5 - 10 |
| Warehouses | 2 |
| Waiting rooms, public | 4 |
| Warehouses | 6 - 30 |
| Wood-working shops | 8 |
Be aware of local regulations and codes.
Fresh air supply - make up air - to a room based on the table above can be calculated as
q = n V (1)
where
q = fresh air supply (ft3/h, m3/h)
n = air change rate (h-1)
V = volume of room (ft3, m3)
Example - Fresh Air Supply to a Public Library
The fresh air supply to a public library with volume 1000 m3 can be calculated as
Q = (4 h-1) (1000 m3)
= 4000 m3/h
Air Volume Calculator
No. of Changes per Hour (h-1)
Room Volume (m3, ft3)
Air Change Out Frequency in minutes
The "Air Change Out Frequency" in minutes can be calculated as
nm = 60 / n (2)
where
nm = Air Change Out Frequency (minutes)