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403.3 Outdoor airflow rate. Ventilation systems shall be designed to have the capacity to supply the minimum outdoor airflow rate determined in accordance with this section. The occupant load utilized for design of the ventilation system shall not be less than the number determined from the estimated maximum occupant load rate indicated in Table 403.3. Ventilation rates for occupancies not represented in Table 403.3 shall be those for a listed occupancy classification that is most similar in terms of occupant density, activities and building construction; or shall be determined by an approved engineering analysis. The ventilation system shall be designed to supply the required rate of ventilation air continuously during the period the building is occupied, except as otherwise stated in other provisions of the code.

With the exception of smoking lounges, the ventilation rates in Table 403.3 are based on the absence of smoking in occupiable spaces. Where smoking is anticipated in a space other than a smoking lounge, the ventilation system serving the space shall be designed to provide ventilation over and above that required by Table 403.3 in accordance with accepted engineering practice.

Exception:
The occupant load is not required to be determined based on the estimated maximum occupant load rate indicated in Table 403.3 where approved statistical data document the accuracy of an alternate anticipated occupant density.

TABLE 403.3
MINIMUM VENTILATION RATES

OCCUPANCY CLASSIFICATION
PEOPLE OUTDOOR AIRFLOW RATE IN BREATHING ZONE, Rp CFM/PERSON
AREA OUTDOOR AIRFLOW RATE IN BREATHING ZONE, Ra CFM/FT2 a
DEFAULT OCCUPANT DENSITY #/1000 FT2 a
EXHAUST AIRFLOW RATE CFM/FT2 a
Correctional facilities        

Cells
   without plumbing fixtures

5
0.12
25

   with plumbing fixturesg

5
0.12
25
1.0

Dining halls
   (see food and beverage service)

Guard stations

5
0.06
15

Day room

5
0.06
30

Booking/waiting

7.5
0.06
50
Dry cleaners, laundries        
   Coin-operated dry cleaner
15
20
   Coin-operated laundries
7.5
0.06
20
   Commercial dry cleaner
30
30
   Commercial laundry
25
10
   Storage, pick up
7.5
0.12
30
Education        
   Auditoriums
5
0.06
150
   Corridors (see public spaces)
   Media center
10
0.12
25
   Sports locker roomsg
0.5
   Music/theater/dance
10
0.06
35
   Smoking loungesb
60
 
70
   Day care (through age 4)
10
0.18
25
   Classrooms (ages 5-8)
10
0.12
25
   Classrooms (age 9 plus)
10
0.12
35
   Lecture classroom
7.5
0.06
65
   Lecture hall (fixed seats)
7.5
0.06
150
   Art classroomg
10
0.18
20
0.7
   Science laboratoriesg
10
0.18
25
1.0
   Wood/metal shopsg
10
0.18
20
0.5
   Computer lab
10
0.12
25
   Multiuse assembly
7.5
0.06
100
   Locker/dressing roomsg
0.25
Food and beverage service        
   Bars, cocktail lounges
7.5
0.18
100
   Cafeteria, fast food
7.5
0.18
100
   Dining rooms
7.5
0.18
70
   Kitchens (cooking)b
0.7
Hospitals, nursing and convalescent homes        
   Autopsy roomsb
0.5
   Medical procedure rooms
15
20
   Operating rooms
30
20
   Patient rooms
25
10
   Physical therapy
15
20
   Recovery and ICU
15
20
Hotels, motels, resorts and dormitories        
   Multipurpose assembly
5
0.06
120
   Bathrooms/toilet—privateg
25/50f
   Bedroom/living room
5
0.06
10
   Conference/meeting
5
0.06
50
   Dormitory sleeping areas
5
0.06
20
   Gambling casinos
7.5
0.18
120
   Lobbies/prefunction
7.5
0.06
30

(continued)


TABLE 403.3—continued MINIMUM VENTILATION RATES


OCCUPANCY CLASSIFICATION
PEOPLE OUTDOOR AIRFLOW RATE IN BREATHING ZONE, Rp CFM/PERSON
AREA OUTDOOR AIRFLOW RATE IN BREATHING ZONE, Ra CFM/FT2 a
DEFAULT OCCUPANT DENSITY #/1000 FT2 a
EXHAUST AIRFLOW RATE CFM/FT2 a
Offices        
   Conference rooms
5
0.06
50
   Office spaces
5
0.06
5
   Reception areas
5
0.06
30
   Telephone/data entry
5
0.06
60
   Main entry lobbies
5
0.06
10
Private dwellings, single and multiple        
   Garages, common for multiple unitsb
0.75
   Garages, separate for each dwellingb
100 cfm per car
   Kitchensb
25/100f
   Living areasc
0.35 ACH but not less than 15 cfm/person
Based upon number of bedrooms. First bedroom, 2; each additional bedroom, 1
   Toilet rooms and bathroomsg
20/50f
Public spaces        
   Corridors
0.06
   Elevator car
1.0
   Shower room (per shower head)g
50/20f
   Smoking loungesb
60
70
   Toilet rooms — publicg
50/70e
   Places of religious worship
5
0.06
120
   Courtrooms
5
0.06
70
   Legislative chambers
5
0.06
50
   Libraries
5
0.12
10
   Museums (children's)
7.5
0.12
40
   Museums/galleries
7.5
0.06
40
Retail stores, sales floors and
showroom floors
       
   Sales (except as below)
7.5
0.12
15
   Dressing rooms
0.25
   Mall common areas
7.5
0.06
40
   Shipping and receiving
0.12
   Smoking loungesb
60
70
   Storage rooms
0.12
   Warehouses (see storage)
Specialty shops        
   Automotive motor-fuel dispensing stationsb
1.5
   Barber
7.5
0.06
25
0.5
   Beauty and nail salonsb, h
20
0.12
25
0.6
   Embalming roomb
2.0
   Pet shops (animal areas)b
7.5
0.18
10
0.9
   Supermarkets
7.5
0.06
8
Sports and amusement        
   Disco/dance floors
20
0.06
100
   Bowling alleys (seating areas)
10
0.12
40
   Game arcades
7.5
0.18
20
   Ice arenas without combustion engines
0.30
0.5
   Gym, stadium, arena (play area)
0.30
   Spectator areas
7.5
0.06
150
   Swimming pools (pool and deck area)
0.48
   Health club/aerobics room
20
0.06
40
   Health club/weight room
20
0.06
10

(continued)


TABLE 403.3—continued
MINIMUM VENTILATION RATES

OCCUPANCY CLASSIFICATION
PEOPLE OUTDOOR AIRFLOW RATE IN BREATHING ZONE, Rp  CFM/PERSON
AREA OUTDOOR AIRFLOW RATE IN BREATHING ZONE, Ra CFM/FT2 a
DEFAULT OCCUPANT DENSITY #/1000 FT2 a
EXHAUST AIRFLOW RATE CFM/FT2 a
Storage        
   Repair garages, enclosed parking garagesb,d
0.75
   Warehouses
0.06
Theaters        
   Auditoriums (see education)
   Lobbies
5
0.06
150
   Stages, studios
10
0.06
70
   Ticket booths
5
0.06
60
Transportation        
   Platforms
7.5
0.06
100
   Transportation waiting
7.5
0.06
100
Workrooms        
   Bank vaults/safe deposit
5
0.06
5
   Darkrooms
1.0
   Copy, printing rooms
5
0.06
4
0.5
   Meat processingc
15
10
   Pharmacy (prep. area)
5
0.18
10
   Photo studios
5
0.12
10
   Computer (without printing)
5
0.06
4


For SI: 1 cubic foot per minute = 0.0004719 m3/s, 1 ton = 908 kg, 1 cubic foot per minute per square foot = 0.00508 m3/(s · m2),
           C = [(F) -32]/1.8, 1 square foot = 0.0929 m2.
 
a. Based upon net occupiable floor area.
 
b. Mechanical exhaust required and the recirculation of air from such spaces is prohibited (see Section 403.2.1, Item 3).
 
c. Spaces unheated or maintained below 50°F are not covered by these requirements unless the occupancy is continuous.
 
d. Ventilation systems in enclosed parking garages shall comply with Section 404.
 
e. Rates are per water closet or urinal. The higher rate shall be provided where periods of heavy use are expected to occur, such as toilets in theaters, schools and sports facilities. The lower rate shall be permitted where periods of heavy use are not expected.
 
f. Rates are per room unless otherwise indicated. The higher rate shall be provided where the exhaust system is designed to operate intermittently. The lower rate shall be permitted where the exhaust system is designed to operate continuously during normal hours of use.
 
g. Mechanical exhaust is required and recirculation is prohibited except that recirculation shall be permitted where the resulting supply airstream consists of not more than 10 percent air recirculated from these spaces (see Section 403.2.1, Items 2 and 4).
 
h. For nail salons, the required exhaust shall include ventilation tables or other systems that capture the contaminants and odors at their source and are capable of exhausting a minimum of 50 cfm per station.