Determine
the number of people occupying the respective building spaces. Find
the CFM/person requirements in Ventilation Rates for Acceptable Indoor
Air Quality (see below). Calculate the required outdoor air volume as
follows:
People
= Occupancy/1000 x Floor Area (ft2)
CFM = People x Outdoor Air Requirement (CFM/person)
Outdoor air
quantities can be reduced to lower levels if proper particulate and
gaseous air filtration equipment is utilized.
Air Change
Method
Find total volume of space to be ventilated. Determine the required
number of air changes per hour.
CFM = Bldg.
Volume (ft3)/Air Change Frequency
Consult local
codes for air change requirements or, in absence of code, refer to “Suggested
Air Changes” (see below).
Heat Removal
Method
When the temperature of a space is higher than the ambient outdoor temperature,
general ventilation may be utilized to provide “free cooling”. Knowing
the desired indoor and the design outdoor dry bulb temperatures, and
the amount of heat removal required (BTU/Hr):
CFM = Heat
Removal (BTU/Hr)/(1.10 x Temp diff)
Ventilation Rates
for Acceptable Air Quality
| Type
of Space |
Outdoor
Air Required
(CFM/person) |
Occupancy
(People/10000ft2)
|
| Auditoriums |
15 |
150 |
| Ballrooms/Discos |
25 |
100 |
| Bars |
30 |
100 |
| Beauty Shops |
25 |
25 |
| Classrooms |
15 |
50 |
| Conference
Rooms |
20 |
50 |
| Correctional
Facility Cells |
20 |
20 |
| Dormitory Sleeping
Rooms |
15 |
20 |
| Dry Cleaners |
30 |
30 |
| Gambling Casinos |
30 |
120 |
| Game Rooms |
25 |
70 |
| Hardware Stores |
15 |
8 |
| Hospital Operating
Rooms |
30 |
20 |
| Hospital Patient
Rooms |
25 |
10 |
| Laboratories |
20 |
30 |
| Libraries |
15 |
20 |
| Medical Procedure
Rooms |
15 |
20 |
| Office Spaces |
20 |
7 |
| Pharmacies |
15 |
20 |
| Photo Studios |
15 |
10 |
| Physical Therapy |
15 |
20 |
| Restaurant
Dining Areas |
20 |
70 |
| Retail Facilities |
15 |
20 |
| Smoking Lounges |
60 |
70 |
| Sporting Spectator
Areas |
15 |
150 |
| Supermarkets |
15 |
8 |
| Theaters |
15 |
150 |
Suggested Air
Changes
| Type
of Space |
Air
Change Frequency
(minutes) |
| Assembly Halls |
3-10 |
| Auditoriums |
4-15 |
| Bakeries |
1-3 |
| Boiler Rooms |
2-4 |
| Bowling Alleys |
2-8 |
| Dry Cleaners |
1-5 |
| Engine Rooms |
1-1.5 |
| Factories (General) |
1-5 |
| Forges |
1-2 |
| Foundries |
1-4 |
| Garages |
2-10 |
| Generating
Rooms |
2-5 |
| Glass Plants |
1-2 |
| Gymnasiums |
2-10 |
| Heat Treat
Rooms |
0.5-1 |
| Kitchens |
1-3 |
| Laundries |
2-5 |
| Locker Rooms |
2-5 |
| Machine Shops |
3-5 |
| Mills (Paper) |
2-3 |
| Mills (Textile) |
5-15 |
| Packing Houses |
2-15 |
| Recreation
Rooms |
2-8 |
| Residence |
2-5 |
| Restaurants |
5-10 |
| Retail Stores |
3-10 |
| Shops (General) |
3-10 |
| Theaters |
3-8 |
| Toilets |
2-5 |
| Transformer
Rooms |
1-5 |
| Turbine Rooms |
2-6 |
| Warehouses |
2-10 |