|OCCUPANCY CATEGORY4||PEOPLE OUTDOOR Air Rate Rp (Cfm/Person)||AREA OUTDOOR Air Rate RA (Cfm/Ft2)||DEFAULT OCCUPANT DENSITY3 (people/1000 ft2)||AIR CLASS|
|Classrooms (ages 5—8)||10||0.12||25||1|
|Classrooms (age 9 plus)||10||0.12||35||1|
|Daycare (through age 4)||10||0.18||25||2|
|Lecture hall (fixed seats)||7.5||0.06||150||1|
|FOOD AND BEVERAGE SERVICE|
|Bars, cocktail lounges||7.5||0.18||100||2|
|Cafeteria/fast food dining||7.5||0.18||100||2|
|Restaurant dining rooms||7.5||0.18||70||2|
|Occupiable storage rooms for liquids or gelsb||5||0.12||2||2|
|HOTELS, MOTELS, RESORTS, DORMITORIES|
|Barracks sleeping areas||5||0.06||20||1|
|Laundry rooms, central||5||0.12||10||2|
|Laundry rooms within dwelling units||5||0.12||10||1|
|Main entry lobbies||5||0.06||10||1|
|Occupiable storage rooms for dry materials||5||0.06||2||1|
|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|
|Sorting, packing, light assembly||7.5||0.12||7||2|
|PUBLIC ASSEMBLY SPACES|
|Auditorium seating area||5||0.06||150||1|
|Places of religious worship||5||0.06||120||1|
|Dwelling unitf, g||5||0.06||See footnotef||1|
|Sales (except as below)||7.5||0.12||15||2|
|Beauty and nail salons||20||0.12||25||2|
|Mall common areas||7.5||0.06||40||1|
|Pet shops (animal areas)||7.5||0.18||10||2|
|SPORTS AND ENTERTAINMENT|
|Bowling alley (seating)||10||0.12||40||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|
|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
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.
- An engineered natural ventilation system where approved by the Authority Having Jurisdiction need not comply with Section 402.2.
- A mechanical ventilation system is not required where:
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 62.1:18.104.22.168]
|Az||=||zone floor area: the net occupiable floor area of the ventilation zone, square feet (m2).|
|Pz||=||zone population: The number of people in the ventilation zone during typical usage.|
|Rp||=||outdoor airflow rate required per person as determined from Table 402.1.|
|Ra||=||outdoor airflow rate required per unit area as determined from Table 402.1. [ASHRAE 62.1:22.214.171.124]|
TABLE 403.2.2 ZONE AIR DISTRIBUTION EFFECTIVENESS1, 2, 3, 4, 5
[ASHRAE 62.1:TABLE 126.96.36.199]
|AIR DISTRIBUTION CONFIGURATION||Ez|
|Ceiling supply of cool air.||1.0|
|Ceiling supply of warm air and floor return.||1.0|
|Ceiling supply of warm air 15°F or more above space temperature and ceiling return.||0.8|
|Ceiling supply of warm air less than 15°F above space temperature and ceiling return provided that the 150 feet per minute (fpm) supply air jet reaches to within 4.5 feet of floor level.||1.06|
|Floor supply of cool air and ceiling return provided that the vertical throw is more than 50 fpm at a height of 4.5 feet or more above the floor.||1.0|
|Floor supply of cool air and ceiling return, provided low-velocity displacement ventilation achieves unidirectional flow and thermal stratification, or underfloor air distribution systems where the vertical throw is 50 fpm or less at a height of 4.5 feet above the floor.||1.2|
|Floor supply of warm air and floor return.||1.0|
|Floor supply of warm air and ceiling return.||0.7|
|Makeup supply drawn in on the opposite side of the room from the exhaust, return, or both.||0.8|
|Makeup supply drawn in near to the exhaust, return, or both locations.||0.5|
For SI units: °C = (°F—32)/1.8, 1 foot per minute = 0.005 m/s, 1 foot = 304.8 mm
1 "Cool air" is air cooler than space temperature.
2 "Warm air" is air warmer than space temperature.
3 "Ceiling supply" includes any point above the breathing zone.
4 "Floor supply" includes any point below the breathing zone.
5 As an alternative to using the above values, Ez shall be permitted to be regarded as equal to air change effectiveness determined in accordance with ASHRAE 129 for air distribution configurations except unidirectional flow.
6 For lower velocity supply air, Ez = 0.8
Voz = Vbz/Ez
Vot = Voz
Vot = Σall zones Voz
Zpz = Voz/Vpz
Vpz is the zone primary airflow, i.e., the primary airflow rate to the ventilation zone from the air handler, including outdoor air and recirculated air. [ASHRAE 62.1:188.8.131.52]
TABLE 403.5.2 SYSTEM VENTILATION EFFICIENCY1, 2, 3
[ASHRAE 62.1:TABLE 184.108.40.206]
|> 0.55||Use Section 404.0|
1 "Max Zpz" refers to the largest value of Zpz, calculated in accordance with Equation 403.5.1, among the ventilation zones served by the system.
2 For values of Max (Zpz) between 0.15 and 0.55, the corresponding value of Ev shall be permitted to be determined by interpolating the values in the table.
3 The values of Ev in this table are based on a 0.15 average outdoor air fraction for the system (i.e., the ratio of the uncorrected outdoor air intake (Vou) to the total zone primary airflow for the zones served by the air handler). For systems with higher values of the average outdoor air fraction, this table is capable of resulting in unrealistically low values of Ev and the use of Section 404.0 is capable of yielding more practical results.
Vou = D Σall zones (Rp•Pz) + Σall zones(Ra•Az)
The occupant diversity ratio (D) shall be determined in accordance with Equation 403.5.3(2) to account for variations in population within the ventilation zones served by the system.
D = Ps/Σall zones Pz
Where the system population (Ps) is the total population in the area served by the system.
Exception: Alternative methods to account for occupant diversity shall be permitted, provided that the resulting (Vou) value is not less than that determined in accordance with Equation 403.5.3(1). [ASHRAE 62.1:220.127.116.11.1]
Vot = Vou/Ev
T = 3v/Vbz
|T||=||averaging time period, minutes.|
|v||=||the volume of the ventilation zone for which averaging is being applied, cubic foot (m3).|
|Vbz||=||the breathing zone outdoor airflow determined in accordance with Equation 403.2.1 and design value of the zone population (Pz), cubic foot per minute (cfm) (m3/min).|
Acceptable design adjustments based on this optional provision shall be in accordance with the following:
- Zones with fluctuating occupancy: The zone population (Pz) shall be permitted to be averaged over time (T).
- Zones with intermittent interruption of supply air: The average outdoor airflow supplied to the breathing zone over time (T) shall be not less than the breathing zone outdoor airflow (Vbz) calculated using Equation 403.2.1.
- Systems with intermittent closure of the outdoor air intake: The average outdoor air intake over time (T) shall be not less than the minimum outdoor air intake (Vot) calculated using Equation 403.3, Equation 403.4, or Equation 403.5.4. [ASHRAE 62.1:18.104.22.168]
- Mechanical ventilation systems shall be permitted to operate intermittently where the system is designed to operate automatically upon detection of vehicle operation or the presence of occupants by approved automatic detection devices.
- Approved automatic carbon monoxide sensing devices shall be permitted to be employed to modulate the ventilation system to not exceed a maximum average concentration of carbon monoxide of 50 parts per million during an eight-hour period, with a concentration of not more than 200 parts per million for a period not exceeding one hour. Automatic carbon monoxide sensing devices installed to modulated parking garage ventilation systems shall be approved in accordance with Section 301.2.
TABLE 403.7 MINIMUM EXHAUST RATES
[ASHRAE 62.1:TABLE 6.5]
|OCCUPANCY CATEGORY8||EXHAUST RATE (cfm/unit)||EXHAUST RATE (cfm/ft2)||AIR CLASS|
|Auto repair rooms1||—||1.50||2|
|Beauty and nail salons||—||0.60||2|
|Cells with toilet||—||1.00||2|
|Copy, printing rooms||—||0.50||2|
|Educational science laboratories||—||1.00||2|
|Janitor closets, trash rooms, recycling||—||1.00||3|
|Kitchens — commercial||—||0.70||2|
|Locker rooms for athletic, industrial and health care facilities||—||0.50||2|
|Other locker rooms||—||0.25||2|
|Shower rooms7, 10||20/50||—||2|
|Paint spray booths||—||—||4|
|Pet shops (animal areas)||—||0.90||2|
|Refrigerating machinery rooms6||—||—||3|
|Residential — kitchens7||50/100||—||2|
|Soiled laundry storage rooms||—||1.00||3|
|Storage rooms, chemical||—||1.50||4|
|Toilets — private5, 9||25/50||—||2|
|Toilets — public4, 9||50/70||—||2|
For SI units: 1 cubic foot per minute = 0.0283 m3/min, 1 square foot = 0.0929 m2
1 Stands where engines are run shall have exhaust systems that directly connect to the engine exhaust and prevent escape of fumes.
2 Where combustion equipment is intended to be used on the playing surface, additional dilution ventilation, source control, or both shall be provided.
3 Exhaust rate is not required for open parking garages as defined in accordance with the building code.
4 Rate is per water closet, urinal, or both. Provide the higher rate where periods of heavy use are expected to occur, e.g., toilets in theatres, schools, and sports facilities. Otherwise the lower rate shall be permitted to be used.
5 Rate is for a toilet room intended to be occupied by one person at a time. For continuous system operation during normal hours of use, the lower rate shall be permitted to be used. Otherwise the higher rate shall be used.
7 For continuous system operation, the lower rates shall be permitted. Otherwise the higher rate shall be used.
9 Exhaust air that has been cleaned in accordance with the criteria of Class 1 shall be permitted to be recirculated.
10 Rate is per shower head.
Ev = minimum (Evz)
Xs = Vou/Vps
The uncorrected outdoor air intake (Vou) shall be determined in accordance with Section 403.5.3, and the system primary airflow (Vps) shall be determined at the condition analyzed. [ASHRAE 62.1:A1.1]
Evz = 1+Xs—Zpz
The average outdoor air fraction for the system (Xs) shall be determined in accordance with Equation 404.2 and the primary outdoor air fraction for the zone (Zpz) shall be determined in accordance with Section 403.5.1. [ASHRAE 62.1:A1.2.1]
Evz = (Fa+Xs•Fb—Zpz•Ep•Fc)/Fa
The system air fractions Fa, Fb, and Fc shall be determined in accordance with Equation 404.3.2(2), Equation 404.3.2(3), and Equation 404.3.2(4). The zone primary air fraction (Ep) shall be determined in accordance with Equation 404.3.2(5). For single-zone and single-supply systems Ep shall equal to 1.0. The zone secondary recirculation fraction (Er) shall be determined by the designer based on system configuration. The zone air distribution effectiveness (Ez) shall be determined in accordance with Section 403.2.2. [ASHRAE 62.1:A1.2.2]
Ep - Primary air fraction: The fraction of primary air in the discharge air to the ventilation zone.
Er - Secondary recirculation fraction: In systems with secondary recirculation of return air, the fraction of secondary recirculated air to the zone that is representative of average system return air rather than air directly recirculated from the zone.
Evz - Zone ventilation efficiency: The efficiency with which the system distributes air from the outdoor air intake to the breathing zone in any particular ventilation zone.
Fb - Mixed air fraction: The fraction of supply air to the ventilation zone from fully mixed primary air.
Fc - Outdoor air fraction: The fraction of outdoor air to the ventilation zone from sources of air outside the zone.
Vpz - Zone primary airflow: Determine in accordance with Section 403.5.1.
Xs - Average outdoor air fraction: At the primary air handler, the fraction of outdoor air intake flow in the system primary airflow.
Zpz - Primary outdoor air fraction: The outdoor air fraction required in the primary air supplied to the ventilation zone prior to the introduction of secondary recirculation air. [ASHRAE 62.1:A3]