Whole-house fans, exhaust terminations and required controls

Grounded in the retrieved California Residential Code — click a citation to read the verbatim passage:

• CRC § 90.1 High relevance — show source text

  [ASHRAE 90.1:6.4.3.7] E 502.10.5 Other Controls. Where setback, zoned, humidity and cooling controls and equipment are provided, they shall be designed and installed in accordance with Section E 502.10 through Section E 502.10.3.1.

  [ASHRAE 90.2-2007:6.10.3.3]

  E 502.11 Whole House Fans. Whole house exhaust fans

  shall have insulated louvers or covers which close where the

  fan is off. Covers or louvers shall have an insulation value of not less than R-4.2, and shall be installed in accordance with the manufacturer’s installation instructions. The attic openings shall be sufficient to accommodate the ventilation capacity of the whole house fan. The operation of the whole house fan shall be considered in determining the adequacy of providing combustion air in accordance with this code. E 502.12 Dampers. Dampers shall be installed to close off outdoor air inlets and exhaust outlets where the ventilation system is not operating.

  E 503.0 Heating, Ventilation, and Air-Conditioning – Other than Low-Rise Residential Buildings. E 503.1 General. The heating, ventilation, and air-conditioning in buildings, other than single-family houses, multi-family structures of not more than three stories above grade, and modular houses, shall be in accordance with Section E 503.0.

  E 503.1.1 New Buildings. Mechanical equipment and systems serving the heating, cooling, ventilating, or refrigeration needs of new buildings shall comply with the requirements of this section as described in Section E 503.2. [ASHRAE 90.1:6.1.1.1]

  E 503.1.2 Additions to Existing Buildings. Mechanical equipment and systems serving the heating, cooling, ventilating, or refrigeration needs of additions to existing buildings shall be in accordance with the requirements of this section as described in Section E 503.2.

  Exception: Where HVACR to an addition is provided by existing HVACR systems and equipment, such existing systems and equipment shall not be required to be in accordance with this appendix. A new system or equipment installed shall be in accordance with specific requirements applicable to those systems and equipment.

  [ASHRAE 90.1:6.1.1.2]

  E 503.1.3 Alterations to Heating, Ventilating, Air- Conditioning, and Refrigeration in Existing Buildings. New HVACR equipment as a direct replacement of existing HVACR equipment shall comply with the following sections as applicable for the equipment being replaced:

  (1) Section E 503.3 “Simplified Approach Option for HVAC Systems”

  (2) Section E 503.4 “Equipment Efficiencies, Verification, and Labeling Requirements”

  (3) Section E 503.4.6 “Zone Thermostatic Controls”

  (4) Section E 503.4.6.2 “Set-point Overlap Restrictions”

  (5) Section E 503.4.6.3 “Off-Hour Controls” except for Section E 503.4.6.3.4, “Zone Isolation”

  (6) Section E 503.4.6.4 “Ventilation System Controls”

  (7) Section E 503.4.6.8 “Freeze Protection and Snow/Ice Melting Systems”

• CRC § 502.10.3 High relevance — show source text

  ), Copyright © 2025 IAPMO, and may not be used for any other purpose or distributed to any other persons or parties.

  APPENDIX E

  E 502.10.3 Humidity Control. Where additional energy-consuming equipment is provided for adding moisture to maintain specific selected relative humidities in spaces or zones, a humidistat shall be provided. This device shall be capable of being set to prevent energy from being used to produce relative humidity within the space above 30 percent. [ASHRAE 90.2-2007:6.10.3.1] E 502.10.3.1 Cooling. Where additional energyconsuming equipment is provided for reducing humidity, it shall be equipped with controls capable of being set to prevent energy from being used to produce a relative humidity within the space below 50 percent during periods of human occupancy and below 60 percent during unoccupied periods.

  [ASHRAE 90.2-2007:6.10.3.2] E 502.10.4 Freeze Protection Systems and Snow/Ice Melting. Freeze protection systems, such as heat tracing of outdoor piping and heat exchangers, including self-regulating heat tracing, shall include automatic controls capable of and configured to shut off the systems where outdoor air temperatures are above 40°F (4°C) or where the conditions of the protected fluid will prevent freezing. Snow- and ice-melting systems shall include automatic controls capable of and configured to shut off the systems where the pavement temperature is above 50°F (10°C) and no precipitation is falling and an automatic or manual control that will allow shutoff where the outdoor temperature is above 40°F (4°C) so that the potential for snow or ice accumulation is negligible.

  [ASHRAE 90.1:6.4.3.7] E 502.10.5 Other Controls. Where setback, zoned, humidity and cooling controls and equipment are provided, they shall be designed and installed in accordance with Section E 502.10 through Section E 502.10.3.1.

  [ASHRAE 90.2-2007:6.10.3.3]

  E 502.11 Whole House Fans. Whole house exhaust fans

  shall have insulated louvers or covers which close where the

  fan is off. Covers or louvers shall have an insulation value of not less than R-4.2, and shall be installed in accordance with the manufacturer’s installation instructions. The attic openings shall be sufficient to accommodate the ventilation capacity of the whole house fan. The operation of the whole house fan shall be considered in determining the adequacy of providing combustion air in accordance with this code. E 502.12 Dampers. Dampers shall be installed to close off outdoor air inlets and exhaust outlets where the ventilation system is not operating.

  E 503.0 Heating, Ventilation, and Air-Conditioning – Other than Low-Rise Residential Buildings. E 503.1 General. The heating, ventilation, and air-conditioning in buildings, other than single-family houses, multi-family structures of not more than three stories above grade, and modular houses, shall be in accordance with Section E 503.0.

  E 503.1.1 New Buildings. Mechanical equipment and systems serving the heating, cooling, ventilating, or refrigeration needs of new buildings shall comply with the requirements of this section as described in Section E 503.2. [ASHRAE 90.1:6.1.1.1]

• CRC § 1.5 High relevance — show source text

  HSPF2 means heating seasonal performance factor.
  9. When whole-house fans are required (REQ), only those whole-house fans that are listed in the Home Ventilating Institute Certified Products Directory may be installed.
  Compliance requires installation of one or more WHFs whose total airflow cfm is capable of meeting or exceeding a minimum 1.5 cfm/square foot of conditioned floor area as
  specified by Section 150.1(c)12.
  10. A supplemental heating unit may be installed in a space served directly or indirectly by a primary heating system, provided that the unit thermal capacity does not exceed 2
  kilowatts or 7,000 Btu/h and is controlled by a time-limiting device not exceeding 30 minutes.
  11. For duct and air handler location: REQ denotes location in conditioned space. When the table indicates ducts and air handlers are in conditioned space, a verification is
  required as specified by Reference Residential Appendix RA3.1.4.3.8.
  12. New dwelling units with a conditioned floor area of 500 square feet or less in Climate Zone 5 may comply with a maximum_U_-factor of 0.30.
  13. Option B meets §150.1(c)9A.
  14. Option C meets §150.1(c)9B.|

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  SINGLE-FAMILY RESIDENTIAL BUILDINGS—PERFORMANCE AND PRESCRIPTIVE COMPLIANCE APPROACHES

  TABLE 150.1-B — RESERVED

  TABLE 150.1-C—CFA AND DWELLING UNIT ADJUSTMENT FACTORS	Col2	Col3
  CLIMATE ZONE	A—CFA	B—DWELLING UNITS
  1	0.793	1.27
  2	0.621	1.22
  3	0.628	1.12
  4	0.586	1.21
  5	0.585	1.06
  6	0.594	1.23
  7	0.572	1.15
  8	0.586	1.37
  9	0.613	1.36
  10	0.627	1.41
  11	0.836	1.44
  12	0.613	1.40
  13	0.894	1.51
  14	0.741	1.26
  15	1.56	1.47
  16	0.59	1.22

  Note: Authority: Sections 25213, 25218, 25218.5, 25402, 25402.1, and 25605, Public Resources Code. Reference: Sections 25007, 25008, 25218.5, 25310, 25402, 25402.1, 25402.4, 25402.5, 25402.8, 25605, and 25943, Public Resources Code.

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  9 SINGLE-FAMILY RESIDENTIAL BUILDINGS—ADDITIONS AND

• CRC § 62.2 High relevance — show source text

  Local exhaust fans shall be permitted to be part of a mechanical exhaust system. Where local exhaust fans are used to provide dwelling-unit ventilation, the local exhaust airflow shall be permitted to be credited toward the dwelling-unit ventilation airflow requirement. Outdoor air ducts connected to the return side of an air handler shall be permitted as supply ventilation where manufacturer’s requirements for return air temperature are met. See ASHRAE Indoor Air Quality Guide for guidance on selection of methods. [ASHRAE 62.2:4.2] E 605.1.5 Airflow Measurement. The airflow required by this section shall be the quantity of outdoor ventilation air supplied and/or indoor air exhausted by the mechanical ventilation system as installed and shall be measured according to the ventilation equipment manufacturer’s installation instructions, or by using a flow hood, flow grid, or other airflow measuring device at the mechanical ventilation fan’s inlet terminals/grilles, outlet terminals/grilles, or in the connected ventilation ducts. Balanced mechanical ventilation system airflow shall be the average of the supply fan and exhaust fan flows. Ventilation airflow of systems with multiple operating modes shall be tested in all modes designed to meet this section.

  [ASHRAE 62.2:4.3] E 605.1.6 Control and Operation. A readily accessible manual ON-OFF control, including but not limited to a fan switch or a dedicated branch-circuit overcurrent device, shall be provided. Controls shall include text or an icon indicating the system’s function.

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  APPENDIX E

  For the purposes of calculating average relative exposure, a dwelling unit shall be permitted to be treated as unoccupied during a time step only if it is unoccupied for the entire time step. [ASHRAE 62.2:4.5.3] E 605.1.8 Equivalent Ventilation. A dwelling-unit ventilation system shall be designed and operated in such a way as to provide the same or lower annual exposure as would be provided in accordance with Section E 605.1.3. The calculations shall be based on a single zone with a constant contaminant emission rate. The manufacturer, specifier, or designer of the equivalent ventilation system shall certify that the system is in accordance with this intent and provide supporting documentation.

  [ASHRAE 62.2:4.6] E 605.2 Bathroom Exhaust Fans. Except where a whole house energy recovery system is used, a mechanical exhaust fan vented to the outdoors shall be provided in each room containing a bathtub, shower, or tub/shower combination. The ventilation rate shall be not less than 50 ft [3] /min (0.02 m [3] /s) for intermittent operation and 20 ft [3] /min (0.009 m [3] /s) for continuous operation. Fans shall comply with the Energy Star Program.

  E 605.3 Filters. Heating and air conditioning filters shall have a MERV rating of 6 or higher. The air distribution system shall be designed for the pressure drop across the filter.

  E 606.0 Indoor Air Quality for Other than Low-Rise Residential Buildings.

  E 606.1 Minimum Indoor Air Quality. The building shall comply with Chapter 4 or ASHRAE 62.1 for ventilation air supply.

  E 607.0 Environmental Comfort.

• CRC § 503.5.10.1. High relevance — show source text

  (3) Systems in Climate Zones 0A, 1A, 2A, and 3A with at least 80 percent outdoor air and employing exhaust air energy recovery complying with Section E 503.5.10.1.

  (4) Systems that prevent reheating, recooling, or mixing of heated and cooled supply air.

  (5) Systems in which at least 75 percent of the energy for reheating (on an annual basis) is from site recovered energy or on-site renewable energy. [ASHRAE 90.1:6.5.3.5]

  E 503.5.6.5 Fractional Horsepower Fan Motors. Motors for fans that are [1] ⁄ 12 hp (62.1 W) or more and less than 1 hp (0.7 kW) shall be electronically-commutated motors or shall have a motor efficiency of not less than 70 percent where rated in accordance with DOE 10 CFR 431. These motors

  shall also have the means to adjust motor speed for either balancing or remote control. Belt-driven fans shall be permitted to use sheave adjustments for airflow balancing in lieu of a varying motor speed.

  Exceptions:

  (1) Motors in the airstream within fan coils and terminal units that operate when providing heating to the space served.

  (2) Motors installed in space conditioning equipment certified in accordance with Section E

  503.4 through Section E 503.4.4.1.

  (3) Motors shown in Table E 503.5.6.5(1) or Table E 503.5.6.5(2). [ASHRAE 90.1:6.5.3.6]

  E 503.5.6.6 Low Power Fans. Fans that are not

  covered by Section E 503.5.6.5 and having a fan nameplate electrical input power of less than 180 W or having a motor nameplate horsepower less than

  1 / 12 hp (62.1 W) shall meet the fan efficacy requirements specified in ASHRAE 90.1. [ASHRAE 90.1:6.5.3.7]

  E 503.5.6.7 Ventilation Design. The required minimum outdoor air rate is the larger of the minimum outdoor air rate or the minimum exhaust air rate

  required by Chapter 4, ASHRAE 62.1, ASHRAE 62.2, ASHRAE/ASHE 170, or applicable codes or accreditation standards. Outdoor air ventilation systems shall comply with one of the following:

  (1) Design minimum system outdoor air provided shall not exceed 135 percent of the required minimum outdoor air rate.

  (2) Dampers, ductwork, and controls shall be provided that allow the system to supply no more than the required minimum outdoor air rate with a single setpoint adjustment.

  (3) The system includes exhaust air energy recovery complying with Section E 503.5.10.1.

  [ASHRAE 90.1:6.5.3.8]

  E 503.5.6.8 Occupied-Standby Controls. Zones serving only rooms that are required to have automatic partial OFF or automatic full OFF lighting controls in accordance with ASHRAE 90.1, where the Chapter 4 or ASHRAE 62.1 occupancy category permits ventilation air to be reduced to zero when

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• CRC § 150.0 High relevance — show source text

  Filters and heat/energy cores behind access panels, access doors, or grilles located not more than 10 feet above a walking surface inside a space specified above comply with this requirement. Exception to Section 150.0(o)1Civa: 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.
  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.
  3. A walkway from the attic access door to the HRV/ERV. b. IAQ system component accessibility: Fans, motors, heat exchangers, filters and recovery cores shall meet all applicable requirements of California Mechanical Code Section 304.0 accessibility for service. c. Outdoor air intake design: Outdoor air intakes shall comply with California Mechanical Code Section 402.4.1.

  d. Outdoor air intake location and accessibility: To provide access for cleaning, outdoor air intakes shall be accessible. Air intakes located not more than 10 feet above a walking surface comply with this requirement. If located on roofs, they shall meet the requirements of California Mechanical Code Section 304.3.1.

  Exception to Section 150.0(o)1Civd: Outdoor air intake serving equipment with an FID meeting the requirements of Reference Appendix JA17.

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  SINGLE-FAMILY RESIDENTIAL BUILDINGS— MANDATORY FEATURES AND DEVICES

  D. Air filtration. Air filtration shall conform to the specifications in Section 150.0(m)12. Compliance with ASHRAE 62.2 Sections 6.7 (Minimum Filtration) and 6.7.1 (Filter Pressure Drop) shall not be required.

  E. Reserved.

  F. Reserved.

  G. Local mechanical exhaust. A local mechanical exhaust system shall be installed in each kitchen and bathroom. Systems shall be rated for airflow in accordance with ASHRAE 62.2 Section 7.1. i. Nonenclosed kitchens shall have a demand-controlled mechanical exhaust system meeting the requirements of Section 150.0(o)1Giii. ii. Enclosed kitchens and all bathrooms shall have either one of the following alternatives a or b: a. A demand-controlled mechanical exhaust system meeting the requirements of Section 150.0(o)1Giii. b. A continuous mechanical exhaust system meeting the requirements of Section 150.0(o)1Giv. iii. Demand-controlled mechanical exhaust. A local mechanical exhaust system shall be designed to be operated as needed.

  a. Control and operation. Demand-controlled mechanical exhaust systems shall be provided with at least one of the following controls:

  1. A readily accessible occupant-controlled ON-OFF control.
  2. An automatic control that does not impede occupant ON control. b. Ventilation rate and capture efficiency. The system shall meet or exceed either the minimum airflow in accordance with Table 150.0-E or the minimum capture efficiency in accordance with Table 150.0-E, and Table 150.0-G. Capture efficiency ratings shall be determined in accordance with ASTM E3087 and listed in a product directory approved by the Energy Commission.
• CRC § 0.0929 High relevance — show source text

  (1) 60 CFM/person for cultivation, production, and processing facilities or factories.

  (2) 15 CFM/person for centers and dispensaries.

  Ra = outdoor airflow rate required per unit area, 1 CFM/ft [2]

  For SI Units: 1 square foot = 0.0929 m [2], 1 cubic foot per minute =

  0.0283 m [3] /min, 1 cubic foot per minute = 0.4719 L/s, 1 cubic foot per

  minute per square foot = 5.08 [(L/s)/m [2] ]

  Sample Calculation: Determine the outdoor airflow required in the breathing zone ( Vbz ) of an indoor space used for horticultural cultivation with an occupiable floor area of 800 square feet and a maximum of 5 people expected to occupy the zone.

  Sample Solution: Vbz = Rp - Pz + Ra - Az Vbz = (60 CFM/person • 5 people) + (1 CFM • 800 SF) Vbz = 1100 CFM. The ventilation system shall be capable of providing not less than 1100 CFM of outdoor air.

  I 801.1.2 Ventilation System Requirements. When activated by the gas detection system required by Section I 601.1, the mechanical purge ventilation system shall remain on until manually reset. The purge ventilation system ducting shall terminate outdoors in an approved location. The ventilation system shall be designed to operate at a negative pressure of 0.01 inches water column (0.002 kPa) in relation to the exhausted indoor space.

  I 801.1.3 Ventilation for Indoor Cultivation and Storage Spaces. Indoor spaces used for horticultural cultivation and processing and storage shall be provided with ventilation in accordance with Section 402.2. Where

  mechanical ventilation is provided, the systems shall be operational when the indoor space(s) are occupied. Air in indoor cultivation and storage spaces shall be classified as Class 2 Air in accordance with Section 403.9.2.

  I 801.1.4 Exhaust Ventilation Rate. The exhaust and ventilation system required in this section shall not create a lesser standard of installation than prescribed by the

  minimum safety standards adopted by the Authority Having Jurisdiction. Exhaust airflow shall be provided at not less than 0.2 CFM/ft [2] [1.02 (L/s)/m [2] ] of floor area. Exhaust air shall not be used as makeup air, recirculated air, or transfer air. Makeup air shall be provided for more than 150 CFM (70.8 L/s) exhaust. I 801.1.5 Exhaust System Requirements. An exhaust system shall be installed in accordance with Section 505.0 and the following requirements:

  (1) Exhaust outlet location(s) in accordance with Section 502.2.3 for product conveying ducts as classified in Section 505.8.

  (2) Exhaust air shall terminate directly to the outdoors and shall not be directed onto a public way.

  (3) The exhaust inlet shall be not less than 12 inches (305 mm) above the finished floor.

  (4) Chemical fume hoods shall be required for flammable solvent processing, shall be listed, and shall be installed in accordance with the manufacturer’s

  installation instructions.

  (5) Exhaust ducts shall be independent of all other exhaust systems.

  (6) The exhaust rate shall be in accordance with the appliable occupancy category as shown in Table 403.7.

• CRC § 503.4.6.4.3 High relevance — show source text

  E 503.4.6.4.3 Ventilation Fan Controls. Fans with motors more than 0.75 hp (0.56 kW) shall have automatic controls in accordance with Section E 503.4.6.3.1 that are capable of and configured to shut off fans when not required.

  Exception: HVAC systems intended to operate continuously. [ASHRAE 90.1:6.4.3.4.4]

  E 503.4.6.5 Parking Garage Ventilation Sys- tems. Parking garage ventilation systems shall meet all of the following:

  (1) Separate ventilation systems and control systems shall be provided for each parking garage section.

  (2) Control systems for each parking garage section shall automatically detect and control contaminant levels and shall be capable of and configured to reduce fan airflow to 20 percent or less of design capacity.

  (3) The ventilation system for each parking garage section shall have controls and devices that

  result in fan motor demand of no more than 30 percent of design wattage at 50 percent of the design airflow.

  Exception: Garage ventilation systems serving a single parking garage section having a total ventilation system motor nameplate horsepower (kilowatts)

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  APPENDIX E

  not exceeding 5 hp (3.7 kW) at fan system design conditions and where the parking garage section has no mechanical cooling or mechanical heating.

  [ASHRAE 90.1:6.4.3.4.5] E 503.4.6.6 Heat Pump Auxiliary Heat Con- trol. Heat pumps equipped with internal electric resistance heaters shall have controls that prevent supplemental heater operation where the heating load is capable of being met by the heat pump alone during both steady-state operation and setback recovery. Supplemental heater operation shall be permitted during outdoor coil defrost cycles. Exception: Heat pumps whose minimum efficiency is regulated by U.S. National Appliance Energy Conservation Act (NAECA) and whose ratings are in accordance with the requirements shown in Table E 503.7.1(2) and includes the use of an internal electric resistance heating. [ASHRAE 90.1:6.4.3.5] E 503.4.6.7 Humidification and Dehumidifica- tion Control. Humidification and dehumidification

  control shall be in accordance with Section E 503.4.6.7.1 through Section E 503.4.6.7.3. E 503.4.6.7.1 Dehumidification. Humidistatic controls shall not use mechanical cooling to reduce the humidity below the lower of a dew point of 55°F (12.8°C) or relative humidity of 60 percent in the coldest zone served by the system. Exceptions: (1) Lower humidity shall be permitted when operating mechanical cooling for temperature control.

  (2) Systems serving zones where specific humidity levels are required, such as museums and hospitals, and approved by the Authority Having Jurisdiction or required by accreditation standards, and where humidistatic controls are capable of and configured to maintain a dead band of at least 10 percent relative humidity where no active humidification or dehumidification takes place.

• CRC § 2.1 High relevance — show source text

  Exception: The glazed areas shall not be required where artificial light and a local exhaust system are provided. The minimum local exhaust rates shall be 50 cubic feet per minute (25 L/s) for intermittent ventilation or 20 cubic feet per minute (10 L/s) for contin- uous ventilation in accordance with the California Mechanical Code, Chapter 4 . Exhaust air from the space shall be exhausted directly to the outdoors.

  R325.2.1 Bathroom exhaust fans. Each bathroom containing a bathtub, shower or tub/shower combination shall be mechanically ventilated for purposes of humidity control in accordance with the California Mechanical Code, Chapter 4; and the California Green Building Standards Code, Chapter 4, Division 4.5.

  Note: Window operation is not a permissible method of providing bathroom exhaust for humidity control.

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  BUILDING PLANNING

  R325.3 Ventilation. Ventilation air rates shall be in compliance with the California Mechanical Code.

  R325.4 Opening location. Outdoor intake and exhaust openings shall be located in accordance with Sections R325.4.1 and R325.4.2.

  R325.4.1 Intake openings. Mechanical and gravity outdoor air intake openings shall be located not less than 10 feet (3048 mm) from any hazardous or noxious contaminant, such as vents, chimneys, plumbing vents, streets, alleys, parking lots and loading docks.

  For the purpose of this section, the exhaust from dwelling unit toilet rooms, bathrooms and kitchens shall not be considered as hazardous or noxious.

  Exceptions:

  1. The 10-foot (3048 mm) separation is not required where the intake opening is located 3 feet (914 mm) or greater below the contaminant source.

  2. Vents and chimneys serving fuel-burning appliances shall be terminated in accordance with the applicable provisions of the California Mechanical Code.

  3. Clothes dryer exhaust ducts shall be terminated in accordance with the California Mechanical Code.

  R325.4.2 Exhaust openings. Exhaust air shall not be directed onto walkways.

  R325.5 Outside opening protection. Air exhaust and intake openings that terminate outdoors shall be protected with corrosionresistant screens, louvers or grilles having an opening size of not less than [1] / 4 inch (6 mm) and a maximum opening size of [1] / 2 inch (13 mm), in any dimension. Openings shall be protected against local weather conditions. Outdoor air exhaust and intake openings shall meet the provisions for exterior wall opening protectives in accordance with this code.

  R325.6 Interior stairway illumination. Interior stairways shall be provided with an artificial light source to illuminate the landings and treads. The light source shall be capable of illuminating treads and landings to levels of not less than 1 footcandle (11 lux) as measured at the center of treads and landings. There shall be a wall switch at each floor level to control the light source where the stairway has six or more risers.

  Exception: A switch is not required where remote, central or automatic control of lighting is provided.

• CRC § 605.1.3.4 High relevance — show source text

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  E 605.1.3.4(D) Effective Annual Average Infil- tration Rate. Effective Annual Average Infiltration Rate ( Qinf ) shall be calculated using Equation E 605.1.3.4(D):

  [Equation E 605.1.3.4(D)]

  = [NL] [ • ] [wsf] [ • ] [A][f][loor] Qinf (CFM) 7.3

  Where:

  NL = normalized leakage wsf = weather and shielding factor from ASHRAE 62.2 Afloor = floor area of residence, ft [2 ]

  For SI units: 1 cubic foot per minute = 0.4719 L/s

  [ASHRAE 62.2:4.1.2.2] E 605.1.3.5 Different Occupant Density. Table E 605.1.3.1 and Equation E 605.1.3.1 assume two persons in a studio or one-bedroom dwelling unit and an additional person for each additional bedroom. Where higher occupant densities are known, the rate shall be increased by 7.5 ft [3] /min (0.003 m [3] /s) for each additional person. Where approved by the Authority Having Jurisdiction, lower occupant densities shall be permitted to be used. [ASHRAE 62.2:4.1.3] E 605.1.4 System Type. The dwelling-unit mechanical ventilation system shall consist of one or more supply or exhaust fans and associated ducts and controls. Local exhaust fans shall be permitted to be part of a mechanical exhaust system. Where local exhaust fans are used to provide dwelling-unit ventilation, the local exhaust airflow shall be permitted to be credited toward the dwelling-unit ventilation airflow requirement. Outdoor air ducts connected to the return side of an air handler shall be permitted as supply ventilation where manufacturer’s requirements for return air temperature are met. See ASHRAE Indoor Air Quality Guide for guidance on selection of methods. [ASHRAE 62.2:4.2] E 605.1.5 Airflow Measurement. The airflow required by this section shall be the quantity of outdoor ventilation air supplied and/or indoor air exhausted by the mechanical ventilation system as installed and shall be measured according to the ventilation equipment manufacturer’s installation instructions, or by using a flow hood, flow grid, or other airflow measuring device at the mechanical ventilation fan’s inlet terminals/grilles, outlet terminals/grilles, or in the connected ventilation ducts. Balanced mechanical ventilation system airflow shall be the average of the supply fan and exhaust fan flows. Ventilation airflow of systems with multiple operating modes shall be tested in all modes designed to meet this section.

  [ASHRAE 62.2:4.3] E 605.1.6 Control and Operation. A readily accessible manual ON-OFF control, including but not limited to a fan switch or a dedicated branch-circuit overcurrent device, shall be provided. Controls shall include text or an icon indicating the system’s function.

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  APPENDIX E

• CRC § 160.2 High relevance — show source text

  i. Whole-dwelling unit mechanical ventilation . a. Whole-dwelling unit ventilation strategy. The altered ventilation system shall be supply, balanced, or the existing ventilation type being altered. b. Whole-dwelling unit airflow . If the whole-dwelling ventilation fan is altered or replaced, then one of the following Subsections 1 or 2 shall be used for compliance as applicable.

  1. Dwellings that were required by a previous building permit to comply with the whole-dwelling unit airflow requirements in Section 160.2(b)2, 120.1(b) or 150.0(o) shall meet or exceed the wholedwelling unit mechanical ventilation airflow specified in Section 160.2(b)2Aiv or 160.2(b)2Av as confirmed through field verification and diagnostic testing in accordance with the applicable procedures specified in Reference Appendix RA3.7 or NA2.2.

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  on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.

  MULTIFAMILY BUILDINGS—ADDITIONS, ALTERATIONS AND REPAIRS TO EXISTING MULTIFAMILY BUILDINGS

  2. Dwellings that were not required by a previous building permit to have a whole-dwelling unit ventilation system to comply with Section 160.2(b)2, 120.1(b) or 150.0(o) shall not be required to comply with the whole-dwelling unit ventilation airflow specified in Section 160.2(b)2Aiv or 160.2(b)2Av. c. Replacement ventilation fans. Whole-dwelling unit replacement ventilation fans shall be rated for airflow and sound in accordance with the requirements of ASHRAE 62.2 Sections 7.1 and 7.3. Additionally, when conformance to a specified whole-dwelling unit airflow rate is required for compliance, the replacement fans shall be rated at no less than the airflow rate required for compliance. d. Air filters . If the air filtration device for a whole-dwelling unit ventilation system is altered or replaced, then one of the following Subsections 1 or 2 shall be used for compliance.
  3. Dwellings that were required by a previous building permit to comply with the ventilation system air filtration requirements in Section 160.2(b)1, 120.1(b)1 or 150.0(m)12 shall comply with the air filtration requirements in Section 160.2(b)1.
  4. Dwellings that were not required by a previous building permit to comply with the ventilation system air filtration requirements in Section 160.2(b)1, 120.1(b)1 or 150.0(m)12 shall not be required to comply with the air filtration requirements specified in Section 160.2(b)1.

  ii. Local mechanical exhaust .

  a. Bathroom local mechanical exhaust . Altered bathroom local mechanical exhaust systems shall comply with the applicable requirements specified in Section 160.0(b)2Avi. b. Kitchen local mechanical exhaust . If the kitchen local ventilation fan is altered or replaced, then one of the following Subsections 1, 2 or 3 shall be used for compliance. 1.

• CRC § 62.2 High relevance — show source text

  [ASHRAE 62.2:4.6] E 605.2 Bathroom Exhaust Fans. Except where a whole house energy recovery system is used, a mechanical exhaust fan vented to the outdoors shall be provided in each room containing a bathtub, shower, or tub/shower combination. The ventilation rate shall be not less than 50 ft [3] /min (0.02 m [3] /s) for intermittent operation and 20 ft [3] /min (0.009 m [3] /s) for continuous operation. Fans shall comply with the Energy Star Program.

  E 605.3 Filters. Heating and air conditioning filters shall have a MERV rating of 6 or higher. The air distribution system shall be designed for the pressure drop across the filter.

  E 606.0 Indoor Air Quality for Other than Low-Rise Residential Buildings.

  E 606.1 Minimum Indoor Air Quality. The building shall comply with Chapter 4 or ASHRAE 62.1 for ventilation air supply.

  E 607.0 Environmental Comfort.

  E 607.1 Thermal Comfort Controls. The mechanical systems and controls of building shall be designed to provide and maintain indoor comfort conditions in accordance with

  ASHRAE 55.

  E 607.2 Heating and Air-Conditioning System Design. Heating and air-conditioning systems shall be sized, designed, and have their equipment selected in accordance with the following:

  (1) Heat loss and heat gain are established in accordance with ACCA Manual J, ASHRAE handbooks, or other equivalent methods.

  (2) Duct systems shall be sized in accordance with ACCA Manual D, ASHRAE handbooks, or other equivalent methods.

  (3) Heating and cooling equipment in accordance with ACCA Manual S or other equivalent methods.

  E 608.0 Low VOC Solvent Cement and Primer.

  E 608.1 General. Primers and solvent cements used to join plastic pipe, and fittings shall be in accordance with Section E 608.1.1 and Section E 608.1.2.

  E 608.1.1 Solvent Cement. Solvent cement, including one-step solvent cement, shall have a volatile organic compound (VOC) content of less than or equal to 65 ounces per gallon (oz/gal) (487 g/L) for CPVC cement, 68 oz/gal (509 g/L) for PVC cement, and 43 oz/gal (322 g/L) for ABS cement, as determined by the South Coast Air Quality Management District’s Laboratory Methods of Analysis for Enforcement Samples, Method 316A. E 608.1.2 Primer. Primer shall have a volatile organic compound (VOC) content of less than or equal to 73 oz/gal (546 g/L), as determined by the South Coast Air Quality Management District’s Laboratory Methods of Analysis for Enforcement Samples, Method 316A.

  E 701.0 Installer Qualifications.

  E 701.1 Scope. The provisions of this section address minimum qualifications of installers of mechanical systems covered within the scope of this appendix.

  E 702.0 Qualifications.

  E 702.1 General. Where permits are required, the Authority Having Jurisdiction shall have the authority to require contractors, installers, or service technicians to demonstrate competency. Where determined by the Authority Having Jurisdiction, the contractor, installer, or service technician shall be licensed to perform such work.

  Part I