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Ventilation systems shall be designed to have the capacity to supply the minimum outdoor airflow rate, determined in accordance with this section. In each occupiable space, the ventilation system shall be designed to deliver the required rate of outdoor airflow to the breathing zone. The occupant load utilized for design of the ventilation system shall be not less than the number determined from the estimated maximum occupant load rate indicated in Table 403.3.1.1. Ventilation rates for occupancies not represented in Table 403.3.1.1 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 403.3.1.1 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 403.3.1.1 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 403.3.1.1 where approved statistical data document the accuracy of an alternative anticipated occupant density.
MINIMUM VENTILATION RATES
OCCUPANCY CLASSIFICATION OCCUPANT DENSITY
#/1000 FT2a
PEOPLE OUTDOOR AIRFLOW RATE IN BREATHING ZONE, Rp CFM/PERSON AREA OUTDOOR AIRFLOW RATE IN BREATHING ZONE, Ra CFM/FT2a EXHAUST AIRFLOW RATE CFM/FT2a
Correctional facilities        
Booking/waiting 50 7.5 0.06
Cells
without plumbing fixtures
25 5 0.12
with plumbing fixturesg
25 5 0.12 1.0
Day room 30 5 0.06
Dining halls
(see "Food and beverage service")
Guard stations 15 5 0.06
Dry cleaners, laundries        
Coin-operated dry cleaner 20 15
Coin-operated laundries 20 7.5 0.12
Commercial dry cleaner 30 30
Commercial laundry 10   5 0.12
Storage, pick up 30 7.5 0.12
Education        
Art classroomg 20 10 0.18 0.7
Auditoriums 150 5 0.06
Classrooms (ages 5—8) 25 10 0.12
Classrooms (age 9 plus) 35 10 0.12
Computer lab 25 10 0.12
Corridors (see "Public spaces")
Day care (through age 4) 25 10 0.18
Lecture classroom 65 7.5 0.06
Lecture hall (fixed seats) 150 7.5 0.06
Locker/dressing roomsg 0.25
Media center 25 10 0.12
Multiuse assembly 100 7.5 0.06
Music/theater/dance 35 10 0.06
Science laboratoriesg 25 10 0.18 1.0
Smoking loungesb 70 60
Sports locker roomsg 0.5
Wood/metal shopsg 20 10 0.18 0.5
Food and beverage service        
Bars, cocktail lounges 100 7.5 0.18
Cafeteria, fast food 100 7.5 0.18
Dining rooms 70 7.5 0.18
Kitchens (cooking)b 20 7.5 0.12 0.7
Hotels, motels, resorts and dormitories        
Bathrooms/toilet—privateg 25/50 f
Bedroom/living room 10 5 0.06
Conference/meeting 50 5 0.06
Dormitory sleeping areas 20 5 0.06
Gambling casinos 120 7.5 0.18
Lobbies/prefunction 30 7.5 0.06
Multipurpose assembly 120 5 0.06
Offices        
Conference rooms 50 5 0.06
Main entry lobbies 10 5 0.06
Office spaces 5 5 0.06
Reception areas 30 5 0.06
Telephone/data entry 60 5 0.06
Private dwellings, single and multiple        
Garages, common for multiple unitsb 0.75
Kitchensb   50 /100f
Living areasc Based on number of bedrooms. First bedroom, 2; each additional bedroom, 1 0.35 ACH but not less than 15 cfm/person
Toilet rooms and bathroomsg   25 /50f
Public spaces        
Corridors 0.06
Courtrooms 70 5 0.06
Elevator car 1.0
Legislative chambers 50 5 0.06
Libraries 10 5 0.12
Museums (children's) 40 7.5 0.12
Museums/galleries 40 7.5 0.06
Places of religious worship 120 5 0.06
Shower room (per shower head)g 50/20f
Smoking loungesb 70 60
Toilet rooms — publicg 50/70e
Retail stores, sales floors and showroom floors        
Dressing rooms 0.25
Mall common areas 40 7.5 0.06
Sales 15 7.5 0.12
Shipping and receiving 2 10 0.12
Smoking loungesb 70 60
Storage rooms 0.12
Warehouses (see "Storage") 10 0.06
Specialty shops        
Automotive motor fuel-dispensing stationsb 1.5
Barber 25 7.5 0.06 0.5
Beauty salonsb 25 20 0.12 0.6
Embalming roomb 2.0
Nail salonsb, h 25 20 0.12 0.6
Pet shops (animal areas)b 10 7.5 0.18 0.9
Supermarkets 8 7.5 0.06
Sports and amusement        
Bowling alleys (seating areas) 40 10 0.12
Disco/dance floors 100 20 0.06
Game arcades 20 7.5 0.18
Gym, stadium, arena (play area) 7 20 0.18
Health club/aerobics room 40 20 0.06
Health club/weight room 10 20 0.06
Ice arenas without combustion engines 0.30 0.5
Spectator areas 150 7.5 0.06
Swimming pools (pool and deck area) 0.48
Storage        
Refrigerated warehouses/freezers 10
Repair garages, enclosed parking garagesb, d 0.75
Warehouses 10 0.06
Theaters        
Auditoriums (see "Education")
Lobbies 150 5 0.06
Stages, studios 70 10 0.06
Ticket booths 60 5 0.06
Transportation        
Platforms 100 7.5 0.06
Transportation waiting 100 7.5 0.06
Workrooms        
Bank vaults/safe deposit 5 5 0.06
Computer (without printing) 4 5 0.06
Copy, printing rooms 4 5 0.06 0.5
Darkrooms 1.0
Meat processingc 10 15
Pharmacy (prep. area) 10 5 0.18
Photo studios 10 5 0.12
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.
  1. Based on net occupiable floor area.
  2. Mechanical exhaust required and the recirculation of air from such spaces is prohibited. Recirculation of air that is contained completely within such spaces shall not be prohibited (see Section 403.2.1, Item 3).
  3. Spaces unheated or maintained below 50°F are not covered by these requirements unless the occupancy is continuous.
  4. Ventilation systems in enclosed parking garages shall comply with Section 404 .
  5. Rates are per water closet or urinal. The higher rate shall be provided where the exhaust system is designed to operate intermittently. The lower rate shall be permitted only where the exhaust system is designed to operate continuously while occupied.
  6. 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 only where the exhaust system is designed to operate continuously while occupied.
  7. Mechanical exhaust is required and recirculation from such spaces is prohibited. For occupancies other than science laboratories, where there is a wheel - type energy recovery ventilation (ERV) unit in the exhaust system design, the volume of air leaked from the exhaust airstream into the outdoor airstream within the ERV shall be less than 10 percent of the outdoor air volume. Recirculation of air that is contained completely within such spaces shall not be prohibited (see Section 403.2.1, Items 2 and 4).
  8. For nail salons, each manicure and pedicure station shall be provided with a source capture system capable of exhausting not less than 50 cfm per station. Exhaust inlets shall be located in accordance with Section 502.20. Where one or more required source capture systems operate continuously during occupancy, the exhaust rate from such systems shall be permitted to be applied to the exhaust flow rate required by Table 403.3.1.1 for the nail salon.
403.3.1.1.1 Zone Outdoor Airflow
The minimum outdoor airflow required to be supplied to each zone shall be determined as a function of occupancy classification and space air distribution effectiveness in accordance with Sections 403.3.1.1.1.1 through 403.3.1.1.1.3.
403.3.1.1.1.1 Breathing Zone Outdoor Airflow
The outdoor airflow rate required in the breathing zone (Vbz) of the occupiable space or spaces in a zone shall be determined in accordance with Equation 4-1.
(Equation 4-1)
where:

Az = Zone floor area: the net occupiable floor area of the space or spaces in the zone.
Pz = Zone population: the number of people in the space or spaces in the zone.
Rp = People outdoor air rate: the outdoor airflow rate required per person from Table 403.3.1.1.
Ra = Area outdoor air rate: the outdoor airflow rate required per unit area from Table 403.3.1.1.
403.3.1.1.1.2 Zone Air Distribution Effectiveness
The zone air distribution effectiveness (Ez) shall be determined using Table 403.3.1.1.1.2.
ZONE AIR DISTRIBUTION EFFECTIVENESSa,b,c,d
AIR DISTRIBUTION CONFIGURATION Ez
Ceiling or floor supply of cool air 1.0e
Ceiling or floor supply of warm air and floor return 1.0
Ceiling supply of warm air and ceiling return 0.8f
Floor supply of warm air and ceiling return 0.7
Makeup air drawn in on the opposite side of the room from the exhaust or return 0.8
Makeup air drawn in near to the exhaust or return location 0.5
For SI: 1 foot = 304.8 mm, 1 foot per minute = 0.00506 m/s, °C = [(°F) — 32]/1.8.
  1. "Cool air" is air cooler than space temperature.
  2. "Warm air" is air warmer than space temperature.
  3. "Ceiling" includes any point above the breathing zone.
  4. "Floor" includes any point below the breathing zone.
  5. Zone air distribution effectiveness of 1.2 shall be permitted for systems with a floor supply of cool air and ceiling return, provided that low-velocity displacement ventilation achieves unidirectional flow and thermal stratification.
  6. Zone air distribution effectiveness of 1.0 shall be permitted for systems with a ceiling supply of warm air, provided that supply air temperature is less than 15°F above space temperature and provided that the 150-foot-per-minute supply air jet reaches to within 41/2 feet of floor level.
403.3.1.1.1.3 Zone Outdoor Airflow
The zone outdoor airflow rate (Voz), shall be determined in accordance with Equation 4-2.
(Equation 4-2)
403.3.1.1.2 System Outdoor Airflow
The outdoor air required to be supplied by each ventilation system shall be determined in accordance with Sections 403.3.1.1.2.1 through 403.3.1.1.2.3.4 as a function of system type and zone outdoor airflow rates.
403.3.1.1.2.1 Single Zone Systems
Where one air handler supplies a mixture of outdoor air and recirculated return air to only one zone, the system outdoor air intake flow rate (Vot) shall be determined in accordance with Equation 4-3.
(Equation 4-3)
403.3.1.1.2.2 100-Percent Outdoor Air Systems
Where one air handler supplies only outdoor air to one or more zones, the system outdoor air intake flow rate (Vot) shall be determined using Equation 4-4.
(Equation 4-4)
403.3.1.1.2.3 Multiple Zone Recirculating Systems
Where one air handler supplies a mixture of outdoor air and recirculated return air to more than one zone, the system outdoor air intake flow rate (Vot) shall be determined in accordance with Sections 403.3.1.1.2.3.1 through 403.3.1.1.2.3.4.
403.3.1.1.2.3.1 Primary Outdoor Air Fraction
The primary outdoor air fraction (Zp) shall be determined for each zone in accordance with Equation 4-5.
(Equation 4-5)
where:
Vpz = Primary airflow: The airflow rate supplied to the zone from the airhandling unit at which the outdoor air intake is located. It includes outdoor intake air and recirculated air from that air-handling unit but does not include air transferred or air recirculated to the zone by other means. For design purposes, Vpz shall be the zone design primary airflow rate, except for zones with variable air volume supply and Vpz shall be the lowest expected primary airflow rate to the zone when it is fully occupied.
403.3.1.1.2.3.2 System Ventilation Efficiency
The system ventilation efficiency (Ev) shall be determined using Table 403.3.1.1.2.3.2 or Appendix A of ASHRAE 62.1.
SYSTEM VENTILATION EFFICIENCYa, b
Max (Zp) Ev
≤ 0.15 1
≤ 0.25 0.9
≤ 0.35 0.8
≤ 0.45 0.7
≤ 0.55 0.6
≤ 0.65 0.5
≤ 0.75 0.4
> 0.75 0.3
  1. Max (Zp) is the largest value of Zp calculated using Equation 4-5 among all the zones served by the system.
  2. Interpolating between table values shall be permitted.
403.3.1.1.2.3.3 Uncorrected Outdoor Air Intake
The uncorrected outdoor air intake flow rate (Vou) shall be determined in accordance with Equation 4-6.
(Equation 4-6)
where:

D = Occupant diversity: the ratio of the system population to the sum of the zone populations, determined in accordance with Equation 4-7.
(Equation 4-7)
where:

Ps = System population: The total number of occupants in the area served by the system. For design purposes, Ps shall be the maximum number of occupants expected to be concurrently in all zones served by the system.
403.3.1.1.2.3.4 Outdoor Air Intake Flow Rate
The outdoor air intake flow rate (Vot) shall be determined in accordance with Equation 4-8.
(Equation 4-8)

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