The volume of fresh air required for proper ventilation is determined of the size and use of the space ventilated.
The table below can be used as an indication of recommended air changing rates in some common rooms and buildings.
Building / Room Air Change Rates- n - (AC/Hr.)
All spaces in general min 4
Attic spaces for cooling 12 - 15
Auditoriums 8 - 15
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
Clubhouses 20 - 30
Cocktail Lounges 20 - 30
Computer Rooms 15 - 20
Court Houses 4 - 10
Dental Centers 8 - 12
Department Stores 6 - 10
Dining Halls 12 -15
Dining rooms hotels 5
Dress Shops 6 - 10
Drug Shops 6 - 10
Engine rooms 4 - 6
Factory buildings, ordinary 2 - 4
Factory buildings, fumes and 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
Jewelry shops 6 - 10
Kitchens 15 - 60
Laundries 10 - 15
Libraries, public 4
Lunch Rooms 12 -15
Luncheonettes 12 -15
Nightclubs 20 - 30
Malls 6 - 10
Medical Centers 8 - 12
Medical Clinics 8 - 12
Medical Office 8 - 12
Mills, paper 15 - 20
Mills, textile general buildings 4
Mills, textile dyehouses 15 - 20
Municipal Buildings 4 - 10
Museums 12 -15
Offices, public 3
Offices, private 4
Police Stations 4 - 10
Post Offices 4 - 10
Precision Manufacturing 15 - 50
Pump rooms 5
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
Town Halls 4 - 10
Taverns 20 - 30
Theaters 8 - 15
Turbine rooms, electric 5 - 10
Warehouses 2
Waiting rooms, public 4
Note that in many cases local regulations and codes will govern the ventilation requirements.
The fresh air supply to a room can be calculated as
Q = n V (1)
where
Q = fresh air supply (ft3/h, m3/h)
n = air change rate (1/n)
V = volume of room (ft3, m3)
Example - Fresh Air Supply to Public Library
The fresh air supply to a public library with volume 1000 m3 can be calculated as
Q = 4 (1/h) 1000 (m3)
= 4000 m3/h
