The volume of fresh air (make up air) required for proper ventilation is determined of the size and use of the space.

The table below indicates recommended air change rates (air changes per hour) in some common types of rooms and buildings:Building / RoomAir Change Rates- n - (1/hr)

All spaces in generalmin 4

Attic spaces for cooling12 - 15

Auditoriums8 - 15

Bakeries20

Banks4 - 10

Barber Shops6 - 10

Bars20 - 30

Beauty Shops6 - 10

Boiler rooms15 - 20

Bowling Alleys10 - 15

Cafeterias12 - 15

Churches8 - 15

Club rooms12

Clubhouses20 - 30

Cocktail Lounges20 - 30

Computer Rooms15 - 20

Court Houses4 - 10

Dental Centers8 - 12

Department Stores6 - 10

Dining Halls12 -15

Dining rooms (restaurants)12

Dress Shops6 - 10

Drug Shops6 - 10

Engine rooms4 - 6

Factory buildings, ordinary2 - 4

Factory buildings, fumes and moisture10 - 15

Fire Stations4 - 10

Foundries15 - 20

Galvanizing plants20 - 30

Garages repair20 - 30

Garages storage4 - 6

Homes, night cooling10 - 18

Jewelry shops6 - 10

Kitchens15 - 60

Laundries10 - 15

Libraries, public4

Lunch Rooms12 -15

Luncheonettes12 -15

Nightclubs20 - 30

Malls6 - 10

Medical Centers8 - 12

Medical Clinics8 - 12

Medical Offices8 - 12

Mills, paper15 - 20

Mills, textile general buildings4

Mills, textile dye houses15 - 20

Municipal Buildings4 - 10

Museums12 -15

Offices, public3

Offices, private4

Police Stations4 - 10

Post Offices4 - 10

Precision Manufacturing10 - 50

Pump rooms5

Restaurants8 - 12

Retail6 - 10

School Classrooms4 - 12

Shoe Shops6 - 10

Shopping Centers6 - 10

Shops, machine5

Shops, paint15 - 20

Shops, woodworking5

Substation, electric5 - 10

Supermarkets4 - 10

Town Halls4 - 10

Taverns20 - 30

Theaters8 - 15

Turbine rooms, electric5 - 10

Warehouses2

Waiting rooms, public4

Note that in many cases local regulations and codes will govern the ventilation requirements.The fresh air supply to a room can be calculated asq = n V (1)where q = fresh air supply (ft3/h, m3/h)n = air change rate (1/n)V = volume of room (ft3, m3)