Commercial kitchen hoods, grease ducts and hood termination

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

• CMC § 2025 High relevance — show source text

  The building’s structural stability is protected by the regulations for cutting and notching of structural members.

  Chapter 4 Ventilation Air. Chapter 4 regulates the minimum requirements for ventilation air supply, exhaust, and makeup air for occupiable spaces within a building. Building ventilation is one important factor affecting the relationship between airborne transmission of respiratory infections and the health and productivity of workers. Ventilation air may be composed of mechanical or natural ventilation, infiltration, recirculated air, transfer air, or a suitable combination of these. Providing a comfortable and healthy indoor environment for building occupants is of primary concern. When determining ventilation rates, typical and unusual significant sources of indoor pollution need to be controlled. Areas such as kitchens, bathrooms, and laundries are all built to allow specific functions. These spaces produce pollutants such as moisture, odors, volatile organic compounds, particles, or combustion byproducts. The purpose of local exhaust is to control concentrates of these pollutants in the room into which they were emitted and to reduce the spread of pollutants into other parts of the occupancy. Local exhaust ventilation is the source control for pollution that is expected in certain rooms. Using local exhaust to extract contaminants before they mix with the indoor environment is essential.

  Chapter 5 Exhaust Systems. Chapter 5 regulates the minimum requirements for exhaust systems. Chapter 5 contains two parts: Part I provides exhaust requirements for environmental air ducts and product conveying systems; Part II provides exhaust requirements for commercial hoods and kitchen ventilation. Environmental air ducts include exhaust ducts used for transporting the air from domestic kitchens, bathrooms, shower rooms, locker rooms, janitor’s closets, and clothes dryers. Systems that carry nonabrasive exhaust, such as smoke, moderate abrasives such as sawdust, and high abrasives such as manganese or acid vapors use product-conveying ducts. Part II provides the minimum fire safety requirements related to the design, installation, inspection, and maintenance of grease-type operations, such as cooking, for both fuel-gas and solid fuel. Cooking produces a significant amount of smoke, fumes, vapors, heat, and other pollutants. Therefore, acceptable kitchen ventilation is necessary to prevent fires from the build-up of grease and to provide the occupants protection from smoke, unpleasant odors, pollutants, and dangerous gases. There are two types of exhaust hoods (Type I and Type II) used in commercial kitchen applications.

  xiv 2025 CALIFORNIA MECHANICAL CODE

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

  FORMAT OF THE UNIFORM MECHANICAL CODE

  Type I hoods are intended to be installed above equipment or appliances that generate grease or smoke. Type II hoods are intended to be installed above equipment or appliances that generate steam, vapor, heat, or odors and do not generate grease or smoke.

  Chapter 6 Duct Systems. Chapter 6 regulates requirements for ducts and plenums that are portions of a heating, cooling, ventilation, or exhaust system. This chapter contains material and installation requirements for metal, gypsum, factory-made, flexible, and plastic ducts. It also contains provisions for duct insulation, dampers, fire protection, and automatic shutoff for the building’s air distribution system. It is worth noting that exhaust ducts are regulated by Chapter 5, and combustion air ducts are regulated by Chapter 7.

• CMC § 507.6 Medium relevance — show source text

  507.6 Notification of Change . . . . . . . . . 111

  507.7 Pharmaceutical Compounding Exhaust Discharge . . . . . . . . . . . . 111

  508.0 Type I Hoods . . . . . . . . . . . . . . . . 111

  508.1 Where Required . . . . . . . . . . . . . . 111

  508.2 Listed Type I Hood Assemblies . . 111

  508.3 Construction of Type I Hoods . . . . 111

  508.4 Supports . . . . . . . . . . . . . . . . . . . . 112

  508.5 Hood Size . . . . . . . . . . . . . . . . . . . 112

  Table 508.5.1.2 Extra-Heavy-Duty Cooking Appliance Airflow . . . . . . . . . . . . . 113

  Table 508.5.1.3 Heavy-Duty Cooking Appliance

  Airflow. . . . . . . . . . . . . . . . . . . . . . 113

  Table 508.5.1.4 Medium-Duty Cooking Appliance

  Airflow. . . . . . . . . . . . . . . . . . . . . . 113

  Table 508.5.1.5 Light-Duty Cooking Appliance

  Airflow. . . . . . . . . . . . . . . . . . . . . . 113

  508.6 Solid-Fuel Hood Assemblies . . . . 114

  508.7 Exhaust Outlets . . . . . . . . . . . . . . 114

  509.0 Grease Removal Devices in

  Hoods . . . . . . . . . . . . . . . . . . . . . . 114

  509.1 Grease Removal Devices. . . . . . . 114

  509.2 Installation . . . . . . . . . . . . . . . . . . 114

  509.3 Solid-Fuel Grease Removal

  Devices. . . . . . . . . . . . . . . . . . . . . 115

  510.0 Exhaust Duct Systems . . . . . . . . . 115

  510.1 General. . . . . . . . . . . . . . . . . . . . . 115

  510.2 Clearance . . . . . . . . . . . . . . . . . . . 115

  510.3 Openings . . . . . . . . . . . . . . . . . . . 115

  510.4 Listed Grease Ducts . . . . . . . . . . . 116

  510.5 Other Grease Ducts . . . . . . . . . . . 116

  510.6 Exterior Installations . . . . . . . . . . . 117

  xxxii

  510.7 Interior Installations . . . . . . . . . . . 118

  510.8 Underground Installations. . . . . . . 118

  510.9 Termination of Type I Hood Exhaust System . . . . . . . . . . . . . . 119

  510.10 Solid-Fuel Duct Systems . . . . . . . 120

  511.0 Air Movement . . . . . . . . . . . . . . . . 120

  511.1 Exhaust Fans for Commercial

• CMC § 509.1 Medium relevance — show source text

  Hoods . . . . . . . . . . . . . . . . . . . . . . 114

  509.1 Grease Removal Devices. . . . . . . 114

  509.2 Installation . . . . . . . . . . . . . . . . . . 114

  509.3 Solid-Fuel Grease Removal

  Devices. . . . . . . . . . . . . . . . . . . . . 115

  510.0 Exhaust Duct Systems . . . . . . . . . 115

  510.1 General. . . . . . . . . . . . . . . . . . . . . 115

  510.2 Clearance . . . . . . . . . . . . . . . . . . . 115

  510.3 Openings . . . . . . . . . . . . . . . . . . . 115

  510.4 Listed Grease Ducts . . . . . . . . . . . 116

  510.5 Other Grease Ducts . . . . . . . . . . . 116

  510.6 Exterior Installations . . . . . . . . . . . 117

  xxxii

  510.7 Interior Installations . . . . . . . . . . . 118

  510.8 Underground Installations. . . . . . . 118

  510.9 Termination of Type I Hood Exhaust System . . . . . . . . . . . . . . 119

  510.10 Solid-Fuel Duct Systems . . . . . . . 120

  511.0 Air Movement . . . . . . . . . . . . . . . . 120

  511.1 Exhaust Fans for Commercial

  Cooking Operations . . . . . . . . . . . 120

  511.2 Airflow. . . . . . . . . . . . . . . . . . . . . . 121

  511.3 Makeup Air . . . . . . . . . . . . . . . . . . 122

  511.4 Common Duct (Manifold) Systems . . . . . . . . . . . . . . . . . . . . 122

  511.5 Solid-Fuel Air Movement

  Requirements . . . . . . . . . . . . . . . . 122

  512.0 Auxiliary Equipment . . . . . . . . . . . 122

  512.1 Dampers . . . . . . . . . . . . . . . . . . . . 122

  512.2 Electrical Equipment. . . . . . . . . . . 122

  512.3 Other Equipment . . . . . . . . . . . . . 123

  512.4 Solid-Fuel Auxiliary Equipment. . . 123

  513.0 Fire-Extinguishing Equipment. . . . 123

  513.1 General. . . . . . . . . . . . . . . . . . . . . 123

  513.2 Types of Equipment . . . . . . . . . . . 123

  513.3 Simultaneous Operation . . . . . . . . 124

  513.4 Fuel and Electric Power Shutoff . . 125

  513.5 Manual Actuation . . . . . . . . . . . . . 125

  513.6 System Annunciation . . . . . . . . . . 125

  513.7 Special Design and Application . . 125

  513.8 Review and Certification. . . . . . . . 125

• CMC § 2025 Medium relevance — show source text

  Systems that carry nonabrasive exhaust, such as smoke, moderate abrasives such as sawdust, and high abrasives such as manganese or acid vapors use product-conveying ducts. Part II provides the minimum fire safety requirements related to the design, installation, inspection, and maintenance of grease-type operations, such as cooking, for both fuel-gas and solid fuel. Cooking produces a significant amount of smoke, fumes, vapors, heat, and other pollutants. Therefore, acceptable kitchen ventilation is necessary to prevent fires from the build-up of grease and to provide the occupants protection from smoke, unpleasant odors, pollutants, and dangerous gases. There are two types of exhaust hoods (Type I and Type II) used in commercial kitchen applications.

  xiv 2025 CALIFORNIA MECHANICAL CODE

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

  FORMAT OF THE UNIFORM MECHANICAL CODE

  Type I hoods are intended to be installed above equipment or appliances that generate grease or smoke. Type II hoods are intended to be installed above equipment or appliances that generate steam, vapor, heat, or odors and do not generate grease or smoke.

  Chapter 6 Duct Systems. Chapter 6 regulates requirements for ducts and plenums that are portions of a heating, cooling, ventilation, or exhaust system. This chapter contains material and installation requirements for metal, gypsum, factory-made, flexible, and plastic ducts. It also contains provisions for duct insulation, dampers, fire protection, and automatic shutoff for the building’s air distribution system. It is worth noting that exhaust ducts are regulated by Chapter 5, and combustion air ducts are regulated by Chapter 7.

  Chapter 7 Combustion Air. Chapter 7 regulates combustion air requirements for ventilation and dilution of flue gases for appliances installed in buildings. Fuel-gas appliances not regulated by chapter include direct vent appliances and Type I clothes dryers. Makeup air requirements for Type I clothes dryers are located in Chapter 5. Chapter 7 provides acceptable methods for supplying satisfactory combustion air to ensure proper combustion. Combustion air can be supplied by using indoor combustion air or by introducing the air from the outdoors.

  Combustion is the rapid oxidation of fuel to release energy. The oxygen required to release the energy from the fuel normally comes from the air. Incomplete combustion of fuel occurs when inadequate oxygen is provided to the appliance. Combustion is needed to provide ventilation cooling for the casing and internal controls. When a lack of oxygen occurs, some of the carbon is not oxidized, and carbon monoxide forms.

  Chapter 8 Chimneys and Vents. Chapter 8 regulates the installation, design, and construction of venting systems for fuel-burning appliances. The provisions addressed within this chapter follow procedures an installer would use to design or evaluate a venting system. Many requirements apply to the design and construction of venting systems, chimneys, installation of gas vents, and the sizing of venting system for a Category I appliance. Sizing venting systems require rigorous engineering calculations. However, the venting sizing requirements and sizing tables in this chapter already perform the calculations for the benefit of the end user.

  Combustion appliances produce products of incomplete combustion, including potentially harmful carbon monoxide (CO). It is desirable to vent these products to the outdoors. Although the gas is clean-burning fuel, the products of combustion must not be allowed to collect within a building.

• CMC § 508.5.2.1 Medium relevance — show source text

  2025 CALIFORNIA MECHANICAL CODE 113

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  EXHAUST SYSTEMS

  508.5.2.1 Installation. Noncanopy-type commercial cooking hoods shall be installed with the edge of the hood set back not more than 1 foot (305 mm) from the edge of the cooking surface, and the vertical distance between the lip of the hood and the cooking surface shall not exceed 3 feet (914 mm). 508.5.2.2 Capacity. In addition to other requirements for hoods specified in this section, the volume of air exhausting through a noncanopy-type hood to the duct system shall be not less than 300 cubic feet per minute per lineal foot [(ft [3] /min)/ft)] [0.464 (m [3] /s)/m] of cooking equipment. Listed noncanopy exhaust hoods and filters shall be sized and installed in accordance with the terms of their listing and the manufacturer’s installation instructions.

  508.5.3 Labeling. Type I hoods shall bear a label indicating the exhaust flow rate in cubic feet per minute per lineal foot [(m [3] /s)/m].

  508.6 Solid-Fuel Hood Assemblies. Where solid-fuel cooking equipment is to be used, the solid-fuel hood assembly shall be in accordance with Section 517.0.

  508.7 Exhaust Outlets. An exhaust outlet within an unlisted hood shall be located so as to optimize the capture of particulate matter. Each outlet shall serve not more than a 12 foot (3658 mm) section of an unlisted hood.

  509.0 Grease Removal Devices in Hoods.

  509.1 Grease Removal Devices. Listed grease filters or other listed grease removal devices intended for use with commercial cooking operations shall be provided. Listed grease filters and grease removal devices that are removable but not an integral component of a specific listed exhaust hood shall be listed in accordance with UL 1046 and shall be designated on the filter. {NFPA 96:6.1.1, 6.1.2} 509.1.1 Grease Filters, Mesh-Type. Mesh filters shall not be used unless evaluated as an integral part of a listed exhaust hood or listed in conjunction with a primary filter in accordance with UL 1046. {NFPA 96:6.1.3}

  509.2 Installation. The distance between the grease removal device and the cooking surface shall be as great as possible but not less than 18 inches (457 mm). [NFPA 96:6.2.1.1]

  509.2.1 Vertical Distance. Where grease removal devices are used in conjunction with solid fuel or solid fueltype broilers, including gas or electrically heated charbroilers, a minimum vertical distance of 4 feet (1219 mm) shall be maintained between the lower edge of the grease removal device and the cooking surface. [NFPA 96:6.2.1.2]

  Exceptions:

  (1) For cooking equipment without exposed flame and where flue gases bypass grease removal devices, the minimum vertical distance shall be permitted to be reduced to not less than 6 inches (152 mm). [NFPA 96:6.2.1.3]

  (2) Where a grease removal device is listed for separation distances less than those required in Section

• CMC § 506.7 Medium relevance — show source text

  506.7 Supports . . . . . . . . . . . . . . . . . . . . 107

  506.8 Fire Protection . . . . . . . . . . . . . . . 107

  506.9 Protection from Physical Damage . . . . . . . . . . . . . . . . . . . . 107

  xxxi

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  TABLE OF CONTENTS

  506.10 Duct Clearances . . . . . . . . . . . . . . 107

  Table 506.10.4 Basic Minimum Clearances to

  Unprotected Surfaces. . . . . . . . . . 107

  506.11 Clearance Reduction Methods . . . 108

  Table 506.11 Reduction of Duct Clearance with

  Specified Forms of Protection . . . 108

  Part II Commercial Hoods and

  Kitchen Ventilation . . . . . . . . . . . 109

  507.0 General Requirements . . . . . . . . . 109

  507.1 Exhaust Systems . . . . . . . . . . . . . 109

  507.2 Type I Hood Exhaust System Requirements . . . . . . . . . . . . . . . . 109

  507.3 Listed Devices . . . . . . . . . . . . . . . 109

  507.4 Clearance . . . . . . . . . . . . . . . . . . . 109

  507.5 Drawings. . . . . . . . . . . . . . . . . . . . 110

  507.6 Notification of Change . . . . . . . . . 111

  507.7 Pharmaceutical Compounding Exhaust Discharge . . . . . . . . . . . . 111

  508.0 Type I Hoods . . . . . . . . . . . . . . . . 111

  508.1 Where Required . . . . . . . . . . . . . . 111

  508.2 Listed Type I Hood Assemblies . . 111

  508.3 Construction of Type I Hoods . . . . 111

  508.4 Supports . . . . . . . . . . . . . . . . . . . . 112

  508.5 Hood Size . . . . . . . . . . . . . . . . . . . 112

  Table 508.5.1.2 Extra-Heavy-Duty Cooking Appliance Airflow . . . . . . . . . . . . . 113

  Table 508.5.1.3 Heavy-Duty Cooking Appliance

  Airflow. . . . . . . . . . . . . . . . . . . . . . 113

  Table 508.5.1.4 Medium-Duty Cooking Appliance

  Airflow. . . . . . . . . . . . . . . . . . . . . . 113

  Table 508.5.1.5 Light-Duty Cooking Appliance

  Airflow. . . . . . . . . . . . . . . . . . . . . . 113

  508.6 Solid-Fuel Hood Assemblies . . . . 114

  508.7 Exhaust Outlets . . . . . . . . . . . . . . 114

  509.0 Grease Removal Devices in

• CMC § 510.3 Medium relevance — show source text

  118 2025 CALIFORNIA MECHANICAL CODE

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  EXHAUST SYSTEMS

  on the top portion of the grease duct in accordance with Section 510.3 and shall be labeled at the interior portion of the duct.

  510.9 Termination of Type I Hood Exhaust System. The exhaust system shall terminate as follows:

  (1) Outside the building with a fan or duct.

  (2) Through the roof or to the roof from outside, as in Section 510.9.1, or through a wall, as in Section 510.9.2. [NFPA 96:7.8.1] 510.9.1 Rooftop Terminations. Rooftop terminations shall be arranged with or provided with the following:

  (1) A minimum of 10 feet (3048 mm) of horizontal clearance from the outlet to adjacent buildings, property lines, and air intakes.

  (2) A minimum of 5 feet (1524 mm) of horizontal clearance from the outlet (fan housing) to any combustible structure.

  (3) A vertical separation of 3 feet (914 mm) above any air intakes within 10 feet (3048 mm) of the exhaust outlet.

  (4) The ability to drain grease out of any traps or low points formed in the fan or duct near the termination of the system into a collection container that is noncombustible, closed, rainproof, and structurally sound for the service to which it is applied and that will not sustain combustion.

  (5) A grease collection device that is applied to exhaust systems that does not inhibit the performance of any fan.

  (6) Grease collection systems that meet the requirements of Section 510.9.1(4) and Section 510.9.1(5).

  (7) A listed grease duct complying with Section 507.4.7 or ductwork complying with Section 507.4.8.

  (8) A hinged upblast fan supplied with flexible weatherproof electrical cable and service hold-open retainer to permit inspection and cleaning that is listed for commercial cooking equipment with the following conditions:

  (a) Where the fan attaches to the ductwork, the ductwork is a minimum of 18 inches (457 mm) away from any roof surface, as shown in Figure 510.9.1.

  (b) The fan discharges a minimum of 40 inches (1016 mm) away from any roof surface, as shown in Figure 510.9.1.

  (9) Other approved fan, provided it meets all of the following criteria:

  (a) The fan meets the requirements of Section 510.9.1(3) and Section 511.1.3.

  (b) Its discharge or its extended duct discharge meets the requirements of Section 510.9.1(2). (See Section 511.1.3)

  (c) Exhaust fan discharge is directed up and away from the roof surface. {NFPA 96:7.8.2.1}

  For SI units: 1 inch = 25.4 mm, 1 foot = 304.8 mm

  FIGURE 510.9.1

  UPBLAST FAN CLEARANCES

  [NFPA 96: FIGURE 7.8.2.1]

  510.9.1.1 Listed Vibration Isolation Connec-

• CMC § 605.7.6 Medium relevance — show source text

  605.7.6 Flue-fed incinerators in Group I-2. In Group I-2 occupancies, the continued use of existing flue-fed incinerators is prohibited.

  605.7.7 Incinerator inspections in Group I-2. Incinerators in Group I-2 occupancies shall be inspected not less than annually in accordance with the manufacturer’s instructions. Inspection records shall be maintained on the premises and made available to the fire code official upon request.

  605.8 Gas meters. Above-ground gas meters, regulators and piping subject to damage shall be protected by a barrier complying with Section 312 or otherwise protected in an approved manner.

  SECTION 606—COMMERCIAL COOKING EQUIPMENT AND SYSTEMS

  [M] 606.1 General. Commercial kitchen exhaust hoods shall comply with the requirements of the California Mechanical Code .

  [M] 606.2 Where required. A Type I hood shall be installed at or above all commercial cooking appliances and domestic cooking appliances used for commercial purposes that produce grease vapors.

  Exceptions:

  1. Factory-built commercial exhaust hoods that are listed and labeled in accordance with UL 710, and installed in accordance with Section 304.1 of the California Mechanical Code, shall not be required to comply with Sections 507.1.5, 507.2.3, 507.2.5, 507.2.8, 507.3.1, 507.3.3, 507.1.6 and 507.2.10 of the California Mechanical Code .

  2. Factory-built commercial cooking recirculating systems that are listed and labeled in accordance with UL 710B, and installed in accordance with Section 304.1 of the California Mechanical Code, shall not be required to comply with Sections 507.1.5, 507.2.3, 507.2.5, 507.2.8, 507.3.1, 507.3.3, 507.1.6 and 507.2.10 of the California Mechanical Code . Spaces in which such systems are located shall be considered to be kitchens and shall be ventilated in accordance with Table 403.3.1.1 of the California Mechanical Code . For the purpose of determining the floor area required to be ventilated, each individual appliance shall be considered as occupying not less than 100 square feet (9.3 m [2] ).

  3. Where cooking appliances are equipped with integral down-draft exhaust systems and such appliances and exhaust systems are listed and labeled for the application in accordance with NFPA 96, a hood shall not be required at or above them.

  4. A Type I hood shall not be required for an electric cooking appliance where an approved testing agency provides documentation that the appliance effluent contains 5 mg/m [3] or less of grease when tested at an exhaust flow rate of 500 cfm (0.236 m [3] /s) in accordance with UL 710B.

  606.3 Operations and maintenance. Commercial cooking systems shall be operated, inspected and maintained in accordance with Sections 606.3.1 through 606.3.4.

  606.3.1 Ventilation system. The ventilation system in connection with hoods shall be operated at the required rate of air movement, and grease filters listed and labeled in accordance with UL 1046 shall be in place where equipment under a kitchen grease hood is used.

• CMC § 511.3 Medium relevance — show source text

  E NET = E HOOD – MA ID (Equation 511.3)

  Where:

  E NET = net hood exhaust, CFM (L/s)

  E HOOD = total hood exhaust, CFM (L/s)

  MA ID = makeup air, internal discharge, CFM (L/s)

  For SI units: 1 cubic foot per minute = 0.0283 m [3] /min, 1 cubic foot per

  minute = 0.4719 L/s

  511.3.1 Air Balance. Design plans for a facility with a commercial kitchen ventilation system shall include a schedule or diagram indicating the design outdoor air balance. The design outdoor air balance shall indicate the exhaust and replacement air for the facility and the net exfiltration where applicable. The total replacement airflow rate shall equal the total exhaust airflow rate and the net exfiltration.

  511.4 Common Duct (Manifold) Systems. Master kitchen exhaust ducts that serve multiple tenants shall include provision to bleed air from outdoors or from adjacent spaces into the master exhaust duct where required to maintain the necessary minimum air velocity in the master exhaust duct.

  [NFPA 96:8.4.1]

  511.4.1 Connections. Bleed air ducts shall connect to the top or side of the master exhaust duct. [NFPA 96:8.4.2] 511.4.2 Fire Damper. The bleed-air duct shall have a fire damper at least 12 inches (305 mm) from the exhaust duct connection. [NFPA 96:8.4.3]

  511.4.3 Construction and Clearance. The bleed-air

  duct shall have the same construction and clearance requirements as the main exhaust duct from the connection to the exhaust duct to at least 12 inches (305 mm) on both sides of the fire damper. [NFPA 96:8.4.4] 511.4.4 Adjustment. Each bleed air duct shall have a means of adjusting (e.g., by using volume dampers) the bleed air quantity. [NFPA 96:8.4.5] 511.4.5 Adjustment Location. Means to adjust the bleed air quantity shall be installed between the fire damper and the source of bleed air. [NFPA 96:8.4.6]

  511.4.6 Bleed Air Duct. A bleed air duct shall not be used for the exhaust of grease-laden vapors and shall be so labeled. [NFPA 96:8.4.7]

  511.4.7 Disconnect. Unused tenant exhaust connec tions to the master exhaust duct that are not used as bleed

  air connections shall be disconnected and sealed at the main duct. [NFPA 96:8.4.8] 511.5 Solid-Fuel Air Movement Requirements. Where solid-fuel cooking equipment is used, exhaust and replacement air also shall be in accordance with Section 517.0.

  512.0 Auxiliary Equipment.

  512.1 Dampers. Dampers shall not be installed in exhaust ducts or exhaust duct systems. [NFPA 96:9.1.1]

• CMC § 403.3.1.1 Medium relevance — show source text

  Spaces in which such systems are located shall be considered to be kitchens and shall be ventilated in accordance with Table 403.3.1.1 of the California Mechanical Code . For the purpose of determining the floor area required to be ventilated, each individual appliance shall be considered as occupying not less than 100 square feet (9.3 m [2] ). 3. Where cooking appliances are equipped with integral down-draft exhaust systems and such appliances and exhaust systems are listed and labeled for the application in accordance with NFPA 96, a hood shall not be required at or above them.

  4. A Type I hood shall not be required for an electric cooking appliance where an approved testing agency provides documentation that the appliance effluent contains 5 mg/m [3] or less of grease when tested at an exhaust flow rate of 500 cfm (0.236 m [3] /s) in accordance with UL 710B.

  606.3 Operations and maintenance. Commercial cooking systems shall be operated, inspected and maintained in accordance with Sections 606.3.1 through 606.3.4.

  606.3.1 Ventilation system. The ventilation system in connection with hoods shall be operated at the required rate of air movement, and grease filters listed and labeled in accordance with UL 1046 shall be in place where equipment under a kitchen grease hood is used.

  606.3.2 Grease extractors. Where grease extractors are installed, they shall be operated when the commercial-type cooking equipment is used.

  606.3.3 Cleaning. Hoods, grease-removal devices, fans, ducts and other appurtenances shall be cleaned at intervals as required by Sections 606.3.3.1 through 606.3.3.3.

  606.3.3.1 Inspection. Hoods, grease-removal devices, fans, ducts and other appurtenances shall be inspected at intervals specified in Table 606.3.3.1 or as approved by the fire code official. Inspections shall be completed by qualified individuals.

  TABLE 606.3.3.1—COMMERCIAL COOKING SYSTEM INSPECTION FREQUENCY	Col2
  TYPE OF COOKING OPERATIONS	FREQUENCY OF INSPECTION
  High-volume cooking operations such as 24-hour cooking, charbroiling or wok cooking	3 months
  Low-volume cooking operations such as places of religious worship, seasonal businesses and senior centers	12 months
  Cooking operations utilizing solid fuel-burning cooking appliances	1 month
  All other cooking operations	6 months

  606.3.3.2 Grease accumulation. If during the inspection it is found that hoods, grease-removal devices, fans, ducts or other appurtenances have an accumulation of grease, such components shall be cleaned in accordance with ANSI/IKECA C10.

  606.3.3.3 Records. Records for inspections shall state the individual and company performing the inspection, a description of the inspection and when the inspection took place. Records for cleanings shall state the individual and company performing the cleaning and when the cleaning took place. Such records shall be completed after each inspection or cleaning and maintained.

  2025 CALIFORNIA FIRE CODE 6-9

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

  BUILDING SERVICES AND SYSTEMS

• CMC § 508.2.4 Medium relevance — show source text

  508.2.4 Assembly of Listed Exhaust Hoods. Listed exhaust hoods with or without exhaust dampers shall be permitted to be assembled in accordance with the listing requirements. [NFPA 96:5.1.7]

  508.3 Construction of Type I Hoods. The hood or that portion of a primary collection means designed for collecting cooking vapors and residues shall be constructed of and be supported by steel not less than 0.048 of an inch (1.219 mm) (No. 18 MSG), in thickness, stainless steel not less than 0.036 of an inch (0.914 mm) (No. 20 MSG) in thickness, or other approved material of equivalent strength and fire and corrosion resistance. [NFPA 96:5.1.1]

  Exception: Listed exhaust hoods.

  508.3.1 Grease Vapor. Wall-mounted exhaust hood assemblies shall be tight fitting against the back wall so as to not permit passage of grease vapor behind the hood, or between the back wall and the hood assembly. [NFPA 96:5.1.13]

  508.3.2 Seams, Joints, and Penetrations. All seams, joints, and penetrations of the hood enclosure that direct and capture grease-laden vapors and exhaust gases shall have a liquid-tight continuous external weld to the hood’s lower outermost perimeter. [NFPA 96:5.1.2]

  Exceptions:

  (1) Seams, joints, and penetrations of the hood shall be permitted to be internally welded, provided that the weld is formed smooth or ground smooth, so as to not trap grease, and is cleanable. [NFPA 96:5.1.3]

  (2) Penetrations shall be permitted to be sealed by devices that are listed for such use and whose presence does not detract from the hood’s or duct’s structural integrity. [NFPA 96:5.1.5]

  508.3.2.1 Sealed. Internal hood joints, seams, filter support frames, and appurtenances attached inside the hood shall be sealed or otherwise made greasetight. [NFPA 96:5.1.4]

  508.3.3 Eyebrow-Type Hoods. Eyebrow-type hoods over gas or electric ovens shall be permitted to have a duct constructed as required in Section 510.0 from the oven flue(s) connected to the hood canopy upstream of the exhaust plenum, as shown in Figure 508.3.3. [NFPA 96:5.1.8.1]

  2025 CALIFORNIA MECHANICAL CODE 111

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

  EXHAUST SYSTEMS

  FIGURE 508.3.3

  TYPICAL SECTION OF EYEBROW-TYPE HOOD

  [NFPA 96: FIGURE 5.1.8.1]

  508.3.3.1 Duct Connection. The duct connect ing the oven flue(s) to the hood canopy shall be connected with a continuous weld or have a duct-to-duct

  connection. [See Figure 511.1.2(2) through Figure 511.1.2(4)] [NFPA 96:5.1.8.2]

  508.3.4 Insulation. Insulation materials other than

• CMC § 507.2 Medium relevance — show source text

  507.2 Type I Hood Exhaust System Requirements. Cooking equipment used in processes producing smoke or grease-laden vapors shall be equipped with an exhaust system that complies with all the equipment and performance requirements of this chapter. [NFPA 96:4.1.1] All such equipment and its performance shall be maintained in accordance with the requirements of this chapter during all periods of operation of the cooking equipment. [NFPA 96:4.1.2] The following equipment shall be kept in working condition:

  (1) Cooking equipment

  (2) Hoods

  (3) Ducts (if applicable)

  (4) Fans

  (5) Fire-extinguishing equipment

  (6) Special effluent or energy control equipment [NFPA 96:4.1.3]

  Maintenance and repairs shall be performed on all components at intervals necessary to maintain good working conditions. [NFPA 96:4.1.3.1]

  507.2.1 Airflow. All airflows shall be maintained.

  [NFPA 96:4.1.4]

  507.2.2 Responsibility. The responsibility for inspection, testing, maintenance, and cleanliness of the ventilation control and fire protection of the commercial cooking operations, including cooking appliances, shall ultimately be that of the owner of the system, provided that this responsibility has not been transferred in written form to a management company, tenant, or other party.

  [NFPA 96:4.1.5]

  507.2.3 Solid-Fuel Cooking Equipment. All solidfuel cooking equipment shall comply with the requirements of Section 517.0. [NFPA 96:4.1.6]

  507.2.4 Multitenant Applications. Multitenant applications shall require the concerted cooperation of design, installation, operation, and maintenance responsibilities by tenants and by the building owner. [NFPA 96:4.1.7]

  507.2.5 Interior Surfaces. All interior surfaces of the

  exhaust system shall be accessible for cleaning and inspection purposes. [NFPA 96:4.1.8]

  507.2.6 Used in Other Applications. Cooking equipment used in fixed, mobile, or temporary concessions, such as trucks, buses, trailers, pavilions, tents, or any form of roofed enclosure, shall comply with this chapter. {NFPA 96:1.1.3}

  507.3 Listed Devices. Penetrations shall be sealed with listed devices in accordance with the requirements of Section 507.3.1.

  507.3.1 Penetration. Devices that require penetration of a Type I hood or grease duct, such as pipe and conduit penetration fittings and fasteners, shall be listed in accordance with UL 710 or UL 1978. Seams, joints, and penetrations of the hood enclosure shall comply with Section 508.3.2. Seams, joints, and penetrations of the ductwork shall comply with Section 510.5.3. 507.4 Clearance. Where enclosures are not required, hoods, grease removal devices, exhaust fans, and ducts shall have a clearance of at least 18 inches (457 mm) to combustible material, 3 inches (76 mm) to limited-combustible material, and 0 inches (0 mm) to noncombustible material. [NFPA 96:4.2.1]