Exception to 160.2(b)1Bi: For heat recovery ventilators and energy recovery ventilators the location of the filters required by Section 160.2(b)1 may be downstream of a system thermal conditioning component, provided the system is equipped with ancillary filtration upstream of the system’s thermal conditioning component.
ii. All systems shall be designed to accommodate the clean-filter pressure drop imposed by the system air filter(s). The design airflow rate, and maximum allowable clean-filter pressure drop at the design airflow rate applicable to each air filter, shall be determined and reported on labels according to Subsection iv below.
Systems specified in Section 160.2(b)1Ai shall be equipped with air filters that meet either Subsection a or b below:
a. Nominal two-inch minimum depth filter(s) shall be sized by the system designer, or
b. Nominal one-inch minimum depth filter(s) shall be allowed if the filter(s) are sized according to Equation 160.2-A, based on a maximum face velocity of 150 ft per minute, and according to the maximum allowable clean-filter pressure drop specified in Section 160.2(b)1Dii.
Aface = Qfilter / Vface
Where:
Aface = air filter face area, the product of air filter nominal length x nominal width, ft2
Qfilter = design airflow rate for the air filter, ft3/min
Vface = air filter face velocity ≤ 150 ft/min
Exception to Section 160.2(b)2Aiia: The Energy Commission may approve continuous operation of central fan integrated ventilation systems pursuant to Section 10-109(h).
Total Required Ventilation Rate [ASHRAE 62.2:4.1.1].
Equation 160.2-B
Qtot = 0.03Afloor + 7.5(Nbr + 1)
Where:
Qtot = total required ventilation rate, cfm
Afloor = dwelling-unit floor area, ft2
Nbr = number of bedrooms (not to be less than 1)
When using Table 160.2-H for demonstrating compliance, the airflow rating shall be greater than or equal to the value required by Section 160.2(b)2Avi at a static pressure greater than or equal to 0.25 in. of water (62.5 Pa). When a vented range hood utilizes a capture efficiency rating to demonstrate compliance with Section 160.2(b)2Avic2, a static pressure greater than or equal to 0.25 in. of water at the rating point shall not be required, and the airflow listed in the approved directory corresponding to the compliant capture efficiency rating point shall be applied to Table 160.2-H for determining compliance.
Use of Table 160.2-H is limited to ventilation systems that conform to all of the following three specifications:
Exception to Section 160.2(b)2Avif: Kitchen range hoods may be rated for sound at a static pressure determined at working speed as specified in HVI 916 Section 7.2.
xi. Balanced and supply ventilation component accessibility. Balanced and supply ventilation systems shall meet the following requirements for accessibility:
- IAQ filter and HRV/ERV accessibility. System air filters and HRV/ERV heat/energy recovery cores shall be located such that they are accessible for service from within occupiable spaces, basements, garages, balconies, mechanical closets or accessible rooftops. Filters and heat/energy recovery cores behind access panels, access doors, or grilles located no more than 10 feet above a walking surface inside a space specified above comply with this requirement.
Exception to Section 160.2(b)2Axia: Systems that require servicing from inside the attic shall have the following:
1. A Fault Indicator Display (FID) meeting the requirements of Reference Appendix JA17; and
2. An attic access door located in a wall or, where attic access is provided through a ceiling, an attic access hatch that includes an integrated ladder; and
3. A walkway from the attic access door to the HRV/ERV. - IAQ system component accessibility. Fans, motors, heat exchangers, filters and recovery cores shall meet all applicable requirements of California Mechanical Code 304.0 accessibility of service.
Exception to Section 160.2(b)2C: Multifamily buildings with three or fewer habitable stories in Climate Zone 6 are not required to comply with Section 160.2(b)2C.
Exception to Section 160.2(c)1A: For heat recovery ventilators and energy recovery ventilators the location of the filters required by Section 160.2(c)1A may be downstream of a system’s thermal conditioning component, provided the system is equipped with ancillary filtration upstream of the system’s thermal conditioning component.
Note: “Floor area outside that line” refers to the remaining area of the zone that is not bounded by the walls that have the openings and the line drawn between the openings.
Exception to Section 160.2(c)2Aiv: For ceilings that are increasing in height as distance from the opening is increased, the ceiling height shall be determined as the average height of the ceiling within 20 feet from the operable openings. [ASHRAE 62.1:6.4.1.1]
Vz = The larger of Rp x Pz or Ra × Az
Where:
Rp = 15 cubic feet per minute of outdoor airflow per person
Pz = The expected number of occupants. For spaces without fixed seating, the expected number of occupants shall be the expected number specified by the building designer or the default occupancy density in Table 160.2-B times the occupiable floor area of the zone, whichever is greater. For spaces with fixed seating, the expected number of occupants shall be determined in accordance with the California Building Code Section 1004.6.
Ra = The area-based minimum ventilation airflow rate in Table 160.2-B.
Az = The net occupiable floor area of the ventilation zone in square feet.
Exception to Section 160.2(c)3: Transfer air. The rate of outdoor air required by Section 160.2(c)3 may be provided with air transferred from other ventilated space if:
Exception 1 to Section 160.2(c)5A: Demand control ventilation. In intermittently occupied spaces that do not have processes or operations that generate dusts, fumes, mists, vapors or gases and are not provided with local exhaust ventilation (such as indoor operation of internal combustion engines or areas designated for unvented food service preparation), the rate of outdoor air may be reduced if the ventilation system serving the space is controlled by a demand control ventilation device complying with Section 160.2(c)5D or by an occupant sensor ventilation control device complying with Section 160.2(c)5E.
Exception 2 to Section 160.2(c)5A: Temporary reduction. The rate of outdoor air provided to a space may be reduced below the level required by Section 160.2(c) for up to 30 minutes at a time if the average rate for each hour is equal to or greater than the required ventilation rate.
Exception 1 to Section 160.2(c)5C: Where space exhaust is greater than the design ventilation rate specified in Section 160.2(c)3 minus 0.2 cfm per ft² of conditioned area.
Exception 2 to Section 160.2(c)5C: Spaces that have processes or operations that generate dusts, fumes, mists, vapors, or gases and are not provided with local exhaust ventilation, such as indoor operation of internal combustion engines or areas designated for unvented food service preparation, daycare sickrooms, science labs, barber shops or beauty and nail salons shall not install demand control ventilation.
Exception 3 to Section 160.2(c)5C: Spaces with an area of less than 150 square feet, or a design occupancy of less than 10 people as specified by Section 160.2(c)3.
Exception to Section 160.2(c)5Diii: The outdoor air ventilation rate is not required to be larger than the design outdoor air ventilation rate required by Section 160.2(c)3 regardless of CO2 concentration.
Exception to Section 160.2(c)8Bv: When using any energy recovery device, recirculation from leakage, carryover, or transfer from the exhaust side of the energy recovery device is permitted. Recirculated Class 2 air shall not exceed 10% of the outdoor air intake flow.
Exception to Section 160.2(c)8Cii: When using any energy recovery device, recirculation from leakage, carryover, or transfer from the exhaust side of the energy recovery device is permitted. Recirculated Class 3 air shall not exceed 5 percent of the outdoor air intake flow.
Areas
| Space Type | Minimum Occupant Load Density (p/1000 ft²) | Area-based Minimum Ventilation Ra (cfm/ft²) | Air Class | Notes |
| Bars, cocktail lounges | 33 | 0.2 | 2 | |
| Break rooms | 33 | 0.15 | 1 | F |
| Coffee stations | 33 | 0.15 | 1 | F |
| Conference/meeting | 33 | 0.15 | 1 | F |
| Corridors | 5 | 0.15 | 1 | F |
| Computer (not printing) | 5 | 0.15 | 1 | |
| Daycare (through age 4) | 14 | 0.15 | 2 | |
| Dining rooms | 33 | 0.15 | 2 | |
| Disco/dance floors | 100 | 0.15 | 2 | F |
| Freezer and refrigerated spaces (<50ºF) | 0 | 0 | 2 | E |
| Game arcades | 45 | 0.15 | 1 | |
| Gym, sports arena (play area) | 10 | 0.15 | 2 | E |
| Health club/aerobics room/weight rooms | 10 | 0.15 | 2 | |
| Kitchen (cooking) | 3 | 0.15 | 2 | |
| Laundry rooms, central | 5 | 0.15 | 2 | |
| Lobbies/pre-function | 33 | 0.15 | 1 | F |
| Multiuse assembly | 33 | 0.15 | 1 | F |
| Occupiable storage rooms for dry materials | 2 | 0.15 | 1 | |
| Occupiable storage rooms for liquids or gels | 2 | 0.15 | 2 | B |
| Office space | 5 | 0.15 | 1 | F |
| Reception areas | 5 | 0.15 | 1 | F |
| Shipping/receiving | 5 | 0.15 | 2 | B |
| Spectator areas | 33 | 0.15 | 1 | F |
| Swimming (deck) | 33 | 0.15 | 2 | C |
| Swimming (pool surface) | 10 | 0.15 | 2 | C |
| Telephone/data entry | 33 | 0.15 | 1 | F |
| All others | 5 | 0.15 | 2 | |
|
General:
1 The minimum occupant density is one half of the maximum occupant load assumed for egress purposes in the CBC. 2 If this column specifies a minimum cfm/ft2 then it shall be used to comply with Section 160.2(c)5E. 3 For spaces not included in this table, the spaces in Table 120.1-A shall apply. Specific Notes: A – RESERVED B – Rate may not be sufficient where stored materials include those having potentially harmful emissions. C – Rate does not allow for humidity control. “Deck area” refers to the area surrounding the pool that is capable of being wetted during pool use or when the pool is occupied. Deck area that is not expected to be wetted shall be designated as an occupancy category. D – RESREVED. 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 – Ventilation air for this occupancy category shall be permitted to be reduced to zero when the space is in occupied-standby mode. | ||||
| Occupancy Category4 | Exhaust Rate, cfm/ft2 | Exhaust Rate, dm3/ft2 | Air Class | Notes |
| Copy, printing rooms | - | 0.50 | 2 | - |
| Janitor closets, trash rooms, recycling | - | 1.00 | 3 | - |
| Kitchenettes | - | 0.30 | 2 | - |
| Kitchens - commercial | - | 0.70 | 2 | - |
| Locker rooms for athletic or industrial facilities | - | 0.50 | 2 | - |
| All other locker rooms | - | 0.25 | 2 | - |
| Shower rooms | 20/50 | - | 2 | G, H |
| Parking garages | - | 0.75 | 2 | C |
| Pet shops (animal areas) | - | 0.90 | 2 | - |
| Soiled laundry storage rooms | - | 1.00 | 3 | F |
| Storage rooms, chemical | - | 1.50 | 4 | - |
| Toilets - private | 25/50 | - | 2 | E |
| Toilets - public | 50/70 | - | 2 | D |
|
General:
3 For spaces not included in this table, the spaces in Table 120.1-B shall apply. Notes: A –Reserved B –Reserved C – Exhaust shall not be required where two or more sides comprise walls that are at least 50% open to the outside. D – Rate is per water closet, urinal, or both. Provide the higher rate where periods of heavy use are expected to occur. The lower rate shall be permitted to be used otherwise. E – Rate is for a toilet room intended to be occupied by one person at a time. For continuous systems operation during hours of use, the lower rate shall be permitted to be used. Otherwise the higher rate shall be used. F – See other applicable standards for exhaust rate. G – For continuous system operation, the lower rate shall be permitted to be used. Otherwise the higher rate shall be used. H – Rate is per showerhead. | ||||
| Description | Air Class |
| Commercial kitchen grease hoods | 4 |
| Commercial kitchen hoods other than grease | 3 |
| Hydraulic elevator machine rooms | 3 |
| Refrigerating machinery rooms | 3 |
| Application | Compliance Criteria |
| Enclosed Kitchen or Nonenclosed Kitchen | Vented range hood, including appliance-range hood combinations shall meet either the capture efficiency (CE) or the airflow rate specified in Table 160.2-G as applicable. |
| Other kitchen exhaust fans, including downdraft: 300 cfm (150 L/s). | |
| Bathroom | 50 cfm (25 L/s) |
Table 160.2-F: Continuous Local Ventilation Exhaust Airflow Rates
| Application | Airflow |
| Enclosed kitchen | 5 ach, based on kitchen volume |
| Bathroom | 20 cfm (10 L/s) |
Table 160.2-G: Kitchen Range Hood Airflow Rates (cfm) and ASTM E3087 Capture Efficiency (CE)
Ratings According to Dwelling Unit Floor Area and Kitchen Range Fuel Type
| Dwelling Unit Floor Area (ft²) | Hood Over Electric Range | Hood Over Natural Gas Range |
| >1500 | 50% CE or 110 cfm | 70% CE or 180 cfm |
| 1000 - 1500 | 50% CE or 110 cfm | 80% CE or 250 cfm |
| 750 - 1000 | 55% CE or 130 cfm | 85% CE or 280 cfm |
| <750 | 65% CE or 160 cfm | 85% CE or 280 cfm |
Table 160.2-H: Prescriptive Ventilation System Duct Sizing [ASHRAE 62.2:Table 5-3]
| Fan Airflow Rating, cfm at minimum static pressure[0.25 in. water (62.5 Pa)] | <50 (25) | <80 (40) | <100 (50) | <125 (60) | <150 (70) | <175 (85) | <200 (95) | <250 (120) | <350 (165) | <400 (190) | <450 (210) | <700 (330) | <800 (380) |
| Minimum Duct Diameter, in. (mm)a,b For rigid duct | 4 (100) | 5 (125) | 5 (125) | 6 (150) | 6 (150) | 7 (180) | 7 (180) | 8 (205) | 9 (230) | 10 (255) | 10 (255) | 12 (305) | 12 (305) |
| Minimum Duct Diameter, in. (mm)a,b For flex duct | 4 (100) | 5 (125) | 6 (150) | 6 (150) | 7 (180) | 7 (180) | 8 (205) | 8 (205) | 9 (230) | 10 (255) | NP | NP | NP |
|
Footnotes for Table 160.2-H:
a. For noncircular ducts, calculate the diameter as four times the cross-sectional area divided by the perimeter. b. NP = application of the prescriptive table is not permitted for this scenario. c. Use of this table for verification of flex duct systems requires flex duct to be fully extended and any flex duct elbows to have a minimum bend radius to duct diameter ratio of 1.0. d. For this scenario, use of elbows is not permitted. e. For this scenario, 4 in. (100 mm) oval duct shall be permitted, provided the minor axis of the oval is greater than or equal to 3 in. (75 mm) f. When a vented range hood utilizes a capture efficiency rating to demonstrate compliance with 160.2(b)2Avic2, a static pressure greater than or equal to 0.25 in. of water at the rating point shall not be required, and the airflow listed in the approved directory corresponding to the compliant capture efficiency rating point shall be applied to Table 160.2-H for determining compliance. | |||||||||||||
Note: Authority: Sections 25213, 25218, 25218.5, 25402 and 25402.1, Public Resources Code. Reference: Sections 25007, 25008, 25218.5, 25310, 25402, 25402.1, 25402.4, 25402.5, 25402.8, and 25943, Public Resources Code.