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402.1 Occupiable Spaces
Occupiable spaces listed in Table 402.1 shall be designed to have ventilation (outdoor) air for occupants in accordance with this chapter.

TABLE 402.1
MINIMUM VENTILATION RATES IN BREATHING ZONE1, 2
[ASHRAE 62.1:TABLE 6.2.2.1]
OCCUPANCY CATEGORY4 PEOPLE OUTDOOR Air Rate Rp (Cfm/Person) AREA OUTDOOR Air Rate RA (Cfm/Ft2) DEFAULT OCCUPANT DENSITY3 (people/1000 ft2) AIR CLASS
CORRECTIONAL FACILITIES
Booking/waiting
7.5 0.06 50 2
Cell
5 0.12 25 2
Day room
5 0.06 30 1
Guard stations
5 0.06 15 1
EDUCATIONAL FACILITIES
Art classroom
10 0.18 20 2
Classrooms (ages 5-8)
10 0.12 25 1
Classrooms (age 9 plus)
10 0.12 35 1
Computer lab
10 0.12 25 1
Daycare (through age 4)
10 0.18 25 2
Daycare sickroom
10 0.18 25 3
Lecture classroom
7.5 0.06 65 1
Lecture hall (fixed seats)
7.5 0.06 150 1
Media centera
10 0.12 25 1
Multi-use assembly
7.5 0.06 100 1
Music/theater/dance
10 0.06 35 1
Science laboratories
10 0.18 25 2
University/college laboratories
10 0.18 25 2
Wood/metal shop
10 0.18 20 2
FOOD AND BEVERAGE SERVICE
Bars, cocktail lounges
7.5 0.18 100 2
Cafeteria/fast food dining
7.5 0.18 100 2
Kitchen (cooking)
7.5 0.12 20 2
Restaurant dining rooms
7.5 0.18 70 2
GENERAL
Break rooms
5 0.06 25 1
Coffee stations
5 0.06 20 1
Conference/meeting
5 0.06 50 1
Corridors
0.06 1
Occupiable storage rooms for liquids or gelsb
5 0.12 2 2
HOTELS, MOTELS, RESORTS, DORMITORIES
Barracks sleeping areas
5 0.06 20 1
Bedroom/living room
5 0.06 10 1
Laundry rooms, central
5 0.12 10 2
Laundry rooms within dwelling units
5 0.12 10 1
Lobbies/pre-function
7.5 0.06 30 1
Multipurpose assembly
5 0.06 120 1
OFFICE BUILDINGS
Break Rooms
5 0.12 50 1
Main entry lobbies
5 0.06 10 1
Occupiable storage rooms for dry materials
5 0.06 2 1
Office space
5 0.06 5 1
Reception areas
5 0.06 30 1
Telephone/data entry
5 0.06 60 1
MISCELLANEOUS SPACES
Bank or bank lobbies
7.5 0.06 15 1
Bank vaults/safe deposit
5 0.06 5 2
Computer (not printing)
5 0.06 4 1
Freezer and refrigerated spaces (<50°F)e
10 2
General manufacturing (excludes heavy industrial and processes using chemicals)
10 0.18 7 3
Pharmacy (prep. area)
5 0.18 10 2
Photo studios
5 0.12 10 1
Shipping/receivingb
10 0.12 2 2
Sorting, packing, light assembly
7.5 0.12 7 2
Telephone closets
1
Transportation waiting
7.5 0.06 100 1
Warehousesb
10 0.06 2
PUBLIC ASSEMBLY SPACES
Auditorium seating area
5 0.06 150 1
Courtrooms
5 0.06 70 1
Legislative chambers
5 0.06 50 1
Libraries
5 0.12 10 1
Lobbies
5 0.06 150 1
Museums (children's)
7.5 0.12 40 1
Museums/galleries
7.5 0.06 40 1
Places of religious worship
5 0.06 120 1
RESIDENTIAL
Common corridors
0.06 1
5 0.06 See footnotef 1
RETAIL
Sales (except as below)
7.5 0.12 15 2
Barber shop
7.5 0.06 25 2
Beauty and nail salons
20 0.12 25 2
Coin-operated laundries
7.5 0.12 20 2
Mall common areas
7.5 0.06 40 1
Pet shops (animal areas)
7.5 0.18 10 2
Supermarket
7.5 0.06 8 1
SPORTS AND ENTERTAINMENT
Bowling alley (seating)
10 0.12 40 1
Disco/dance floors
20 0.06 100 2
Gambling casinos
7.5 0.18 120 1
Game arcades
7.5 0.18 20 1
Gym, sports arena (play area)e
20 0.18 7 2
Health club/aerobics room
20 0.06 40 2
Health club/weight rooms
20 0.06 10 2
Spectator areas
7.5 0.06 150 1
Stages, studiosd
10 0.06 70 1
Swimming (pool & deck)c
0.48 2
For SI units: 1 cubic foot per minute = 0.0283 m3/min, 1 square foot = 0.0929 m2
Notes:
1 This table applies to no-smoking areas. Rates for smoking-permitted spaces shall be determined using other methods.
2 Volumetric airflow rates are based on an air density of 0.075 pounds of dry air per cubic foot (lbda/ft3) (1.201 kgda/m3), which corresponds to dry air at a barometric pressure of 1 atm (101 kPa) and an air temperature of 70°F (21°C). Rates shall be permitted to be adjusted for actual density, but such adjustment is not required for compliance with this chapter.
3 The default occupant density shall be used where actual occupant density is not known.
4 Where the occupancy category for a proposed space or zone is not listed, the requirements for the listed occupancy category that is most similar in terms of occupant density, activities, and building construction shall be used.
ITEM-SPECIFIC NOTES FOR TABLE 402.1
a For high school and college libraries, use values shown for Public Assembly Spaces — Libraries.
b Rate is capable of not being sufficient where stored materials include those having potentially harmful emissions.
c Rate does not allow for humidity control. Additional ventilation or dehumidification shall be permitted to remove moisture. "Deck area" refers to the area surrounding the pool that would be expected to be wetted during normal pool use, i.e., where the pool is occupied. Deck area that is not expected to be wetted shall be designated as a space type (for example, "spectator area").
d Rate does not include special exhaust for stage effects, e.g., dry ice vapors, smoke.
e Where combustion equipment is intended to be used on the playing surface or in the space, additional dilution ventilation, source control, or both shall be provided.
f Default occupancy for dwelling units shall be two persons for studio and one-bedroom units, with one additional person for each additional bedroom.
g Air from one residential dwelling shall not be recirculated or transferred to other spaces outside of that dwelling.
402.1.1 Construction Documents
The outdoor air ventilation rate and air distribution assumptions made in the design of the ventilation system shall be clearly identified on the construction documents.
402.1.2 Dwelling
Requirements for ventilation air rate for single-family dwellings shall be in accordance with this chapter or ASHRAE 62.2.
402.1.3 Ventilation in Health Care Facilities
Mechanical ventilation for health care facilities shall be designed and installed in accordance with this code and ASHRAE 170.
402.2 Natural Ventilation
Natural ventilation systems shall be designed in accordance with this section and shall include mechanical ventilation systems designed in accordance with Section 403.0, Section 404.0, or both.
Exceptions:
  1. An engineered natural ventilation system where approved by the Authority Having Jurisdiction need not comply with Section 402.2.
  2. A mechanical ventilation system is not required where:
    1. natural ventilation openings comply with the requirements of Section 402.2 and are permanently open or have controls that prevent the openings from being closed during periods of expected occupancy or
    2. the zone is not served by heating or cooling equipment. [ASHRAE 62.1:6.4]
402.2.1 Floor Area to Be Ventilated
Spaces, or portions of spaces, to be naturally ventilated shall be located within a distance based on the ceiling height, in accordance with Section 402.2.1.1, Section 402.2.1.2, or Section 402.2.1.3, from operable wall openings in accordance with Section 402.2.2. For spaces with ceilings which are not parallel to the floor, the ceiling height shall be determined in accordance with Section 402.2.1.4. [ASHRAE 62.1:6.4.1]
402.2.1.1 Single Side Opening
For spaces with operable openings on one side of the space, the distance from the operable openings shall be not more than 2H, where H is the ceiling height. [ASHRAE 62.1:6.4.1.1]
402.2.1.2 Double Side Opening
For spaces with operable openings on two opposite sides of the space, the distance from the operable openings shall be not more than 5H, where H is the ceiling height. [ASHRAE 62.1:6.4.1.2]
402.2.1.3 Corner Openings
For spaces with operable openings on two adjacent sides of a space, such as two sides of a corner, the distance from the operable openings shall be not more than 5H along a line drawn between the two openings that are farthest apart. Floor area outside that line shall comply with Section 402.2.1.1. [ASHRAE 62.1:6.4.1.3]
402.2.1.4 Ceiling Height
The ceiling height, H, to be used in Section 402.2.1.1 through Section 402.2.1.3 shall be the minimum ceiling height in the space.
Exception: For ceilings that are increasing in height as distance from the openings is increased, the ceiling height shall be determined as the average height of the ceiling within 20 feet (6096 mm) from the operable openings. [ASHRAE 62.1:6.4.1.4]
402.2.2 Location and Size of Openings
Spaces, or portions of spaces, to be naturally ventilated shall be permanently open to operable wall openings directly to the outdoors, the openable area of which is a minimum of 4 percent of the net occupiable floor area. Where openings are covered with louvers or otherwise obstructed, openable area shall be based on the net free unobstructed area through the opening. Where interior rooms, or portions of rooms, without direct openings to the outdoors are ventilated through adjoining rooms, the opening between rooms shall be permanently unobstructed and shall have a free area of not less than 8 percent of the area of the interior room nor less than 25 square feet (2.3 m2). [ASHRAE 62.1:6.4.2]
402.2.3 Control and Accessibility
The means to open required operable openings shall be readily accessible to building occupants where the space is occupied. Controls shall be designed to coordinate operation of the natural and mechanical ventilation systems. [ASHRAE 62.1:6.4.3]
402.3 Mechanical Ventilation
Where natural ventilation is not permitted by this section or the building code, mechanical ventilation systems shall be designed, constructed, and installed to provide a method of supply air and exhaust air. Mechanical ventilation systems shall include controls, manual or automatic, that enable the fan system to operate wherever the spaces served are occupied. The system shall be designed to maintain minimum outdoor airflow as required by Section 403.0 under any load conditions.
402.4 Outdoor Air Intake Protection
Required outdoor-air intakes shall be covered with a screen having not less than 1/4 of an inch (6.4 mm) openings, and shall have not more than 1/2 of an inch (12.7 mm) openings.
402.4.1 Weather Protections
Outdoor air intakes that are part of the mechanical ventilation system shall be designed to manage rain entrainment, to prevent rain intrusion, and manage water from snow in accordance with ASHRAE 62.1.

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