516.2 Design Restrictions. All recirculating systems shall
California Mechanical Code (Title 24, Part 4) · 2025 edition · updated 2026-09-10 · California
Italicized text is a California amendment to the model code, as printed in the official publication.
comply with the requirements of Section 516.2.1 through Section 516.2.9. [NFPA 96:14.2]
516.2.1 Gas/Electrically Fueled Cooking Appli- ances. Only gas-fueled or electrically fueled cooking appliances shall be used. Listed gas-fueled equipment designed for use with specific recirculating systems shall have the flue outlets connected in the intended manner. Gas-fueled appliances shall have a minimum 18 inches (457 mm) clearance from the flue outlet to the filter inlet in accordance with Section 509.2.2 through Section 509.2.2.3 and shall meet the installation requirements of this code, NFPA 54/ANSI Z223.1 or NFPA 58. {NFPA 96:14.2.1 – 14.2.3}
516.2.2 Recirculation. Recirculating systems shall be listed with a testing laboratory in accordance with UL 710B or equivalent. [NFPA 96:14.2.4]
516.2.3 Protection. Cooking appliances that require protection and that are under a recirculating hood shall be protected by either the integral fire protection system in accordance with UL 710B or a system in accordance with Section 513.0. [NFPA 96:14.2.4.2]
516.2.4 Maximum Limits. A recirculating system shall not use cooking equipment that exceeds that recirculating system’s labeled maximum limits for that type of equipment, stated in maximum energy input, maximum cooking temperature, and maximum square area of cooking surface or cubic volume of cooking cavity. [NFPA 96:14.2.6]
516.2.5 Label. The listing label shall show the type(s) of cooking equipment tested and the maximum limits specified in Section 516.2.4. [NFPA 96:14.2.7]
516.2.6 Fire Damper. A fire-actuated damper shall be installed at the exhaust outlet of the system. [NFPA 96:14.2.8] The actuation device for the fire damper shall have a maximum temperature rating of 375°F (191°C).
[NFPA 96:14.2.10]
516.2.7 Installation of Electrical Wiring. No electrical wiring shall be installed in the interior sections of the hood plenum that is capable of becoming exposed to grease.
Exception: As permitted by the California Electrical Code . 516.2.8 Power Supply. The power supply of any electrostatic precipitator (ESP) shall be of the “cold spark,” ferroresonant type in which the voltage falls off as the current draw of a short increases. [NFPA 96:14.2.11]
516.2.9 Listing Evaluation. Listing evaluation shall include the following:
(1) Capture and containment of vapors at published and labeled airflows.
(2) Grease discharge at the exhaust outlet of the system not to exceed an average of 2.9 E-09 (oz/in [3] ) (5.0 E-06 kg/m [3] ) of exhausted air sampled from that equipment at maximum amount of product that is capable of
128 2025 CALIFORNIA MECHANICAL CODE
EXHAUST SYSTEMS
being processed over a continuous 8 hour test with the system operating at its minimum listed airflow.
(3) Listing and labeling of clearance to combustibles from all sides, top, and bottom.
(4) Electrical connection in the field in accordance with the California Electrical Code .
(5) Interlocks on all removable components that lie in the path of airflow within the unit to ensure that they are in place during operation of the cooking appliance. {NFPA 96:14.2.12}
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Ask AI about this code▸Contents — California Mechanical Code (Title 24, Part 4)
- Chapter 1 — GENERAL CODE PROVISIONS
- Chapter 2 — DEFINITIONS
- Chapter 3 — GENERAL REGULATIONS
- Chapter 4 — VENTILATION AIR
▸Chapter 5 — EXHAUST SYSTEMS
Overview- 503.1 General. Motors and fans shall be sized to provide
- 503.2 Fans. Parts of fans in contact with explosive or flammab…
- 504.1 General. Where not specified in this chapter, exhaust
- 501.1 Applicability. This chapter includes requirements for
- 502.1 Exhaust Opening Protection. Exhaust openings
- 502.2 Termination of Exhaust Ducts. Exhaust ducts
- 504.2 Independent Exhaust Systems. Single or combined mechanic…
- 504.3 Domestic Cooking Exhaust Equipment.
- 504.4 Clothes Dryers. A clothes dryer exhaust duct shall
- 504.5 Heat Recovery Ventilation (HRV) and Energy
- 505.1 General. A mechanical ventilation or exhaust system
- 505.2 Incompatible Materials. Incompatible materials
- 505.3 Flammability Limit. Unless the circumstances stipulated …
- 505.4 Air-Moving Devices. Air-moving devices shall be
- 505.5 Generating Flames, Sparks, or Hot Materials.
- 505.6 Fire Dampers. Fire dampers shall be permitted to be
- 505.7 Fire Detection, Smoke Control, and Alarm Sys-
- 505.8 Product-Conveying Duct Classifications. Product-conveyin…
- 505.9 Minimum Velocities and Circulation. The velocity and cir…
- 505.10 Makeup Air. Makeup air shall be provided to replenish a…
- 505.11 Hoods and Enclosures. Hoods and enclosures shall
- 505.12 Pharmacies – Compounding Area of Par-
- 506.1 Materials. Materials used in product-conveying duct
- 506.2 Construction. Ducts used for conveying products
- 506.3 Penetrations. Exhaust ducts shall not pass through
- 506.4 Condensate. Joints in duct construction shall be liquidt…
- 506.5 Fittings. Fittings in Class 2, 3, and 4 systems shall be
- 506.6 Explosion Venting. Ducts conveying explosive dusts
- 506.7 Supports. Supports shall be of noncombustible materials,…
- 506.8 Fire Protection. Sprinklers or other fire-protection
- 506.9 Protection from Physical Damage. Ducts and
- 506.10 Duct Clearances. Unless the conditions stipulated
- 506.11 Clearance Reduction Methods. It shall be permitted to p…
- 507.1 Exhaust Systems. Exhaust systems serving Type I
- 507.2 Type I Hood Exhaust System Requirements.
- 507.3 Listed Devices. Penetrations shall be sealed with
- 507.4 Clearance. Where enclosures are not required, hoods,
- 507.5 Drawings. For cooking operations in buildings, a
- 507.6 Notification of Change. If required by the Authority Hav…
- 507.7 Pharmaceutical Compounding Exhaust Dis-
- 508.1 Where Required. Type I hoods shall be installed at
- 508.2 Listed Type I Hood Assemblies. Listed hood
- 508.3 Construction of Type I Hoods. The hood or that
- 508.4 Supports. Hoods shall be secured in place to resist
- 508.5 Hood Size. Hoods shall be sized in accordance with
- 508.6 Solid-Fuel Hood Assemblies. Where solid-fuel
- 508.7 Exhaust Outlets. An exhaust outlet within an
- 509.1 Grease Removal Devices. Listed grease filters or
- 509.2 Installation. The distance between the grease removal
- 509.3 Solid-Fuel Grease Removal Devices. Where
- 510.1 General. Ducts shall not pass through fire walls.
- 510.2 Clearance. Clearance between ducts and combustible
- 510.3 Openings. Openings shall be provided at the sides or
- 510.4 Listed Grease Ducts. Listed grease ducts shall be
- 510.5 Other Grease Ducts. Other grease ducts shall comply with…
- 510.6 Exterior Installations. For cooking operations in
- 510.7 Interior Installations. In all buildings more than one
- 510.8 Underground Installations. Grease ducts installed
- 510.9 Termination of Type I Hood Exhaust System.
- 510.10 Solid-Fuel Duct Systems. Where solid-fuel cooking equip…
- 511.1 Exhaust Fans for Commercial Cooking Opera-
- 511.2 Airflow. The air velocity through a duct shall be not
- 511.3 Makeup Air. The makeup air quantity shall prevent
- 511.4 Common Duct (Manifold) Systems. Master
- 511.5 Solid-Fuel Air Movement Requirements. Where
- 512.1 Dampers. Dampers shall not be installed in exhaust
- 512.2 Electrical Equipment. Wiring systems of any type
- 512.3 Other Equipment. Fume incinerators, thermal recovery uni…
- 512.4 Solid-Fuel Auxiliary Equipment. Where solid fuel
- 513.1 General. Fire-extinguishing equipment for the protection…
- 513.2 Types of Equipment. Fire-extinguishing equipment
- 513.3 Simultaneous Operation. Fixed pipe extinguishing
- 513.4 Fuel and Electric Power Shutoff. Upon actuation of
- 513.5 Manual Actuation. All systems shall have both automatic …
- 513.6 System Annunciation. Upon actuation of an automatic fire…
- 513.7 Special Design and Application. Hoods containing
- 513.8 Review and Certification. Where required, complete
- 513.9 Installation Requirements. Installation of systems
- 513.10 Portable Fire Extinguishers. Portable fire extinguisher…
- 513.11 Maintenance. Portable fire extinguishers shall be
- 513.12 Solid-Fuel Fire-Extinguishing Equipment.
- 514.1 Operating Procedures. Exhaust systems shall be
- 514.2 Inspection, Testing, and Maintenance. Maintenance of the…
- 514.3 Inspection for Grease Buildup. The entire exhaust
- 514.4 Cleaning of Exhaust Systems. If, upon inspection,
- 514.5 Cooking Equipment Maintenance. Inspection and
- 515.1 Cooking Equipment. Cooking equipment shall be
- 515.2 Operating Controls. Deep-fat fryers shall be equipped
- 516.1 General Requirements. Recirculating systems containing o…
- 516.2 Design Restrictions. All recirculating systems shall
- 516.3 Interlocks. The recirculating system shall be provided
- 516.4 Location and Application Restrictions. The
- 516.5 Additional Fire Safety Requirements. In addition to the …
- 516.6 Use and Maintenance. Automatic or manual covers on cooki…
- 517.1 Venting Application. Venting requirements of solidfuel c…
- 517.2 Location of Appliances. For cooking operations in
- 517.3 Hoods for Solid-Fuel Cooking. Hoods shall be sized
- 517.4 Exhaust Systems for Solid-Fuel Cooking. Where
- 517.5 Grease Removal Devices for Solid-Fuel Cook-
- 517.6 Air Movement for Solid-Fuel Cooking. Exhaust
- 517.7 Fire-Extinguishing Equipment for Solid-Fuel
- 517.8 Other Safety Requirements. Metal-fabricated solidfuel co…
- 518.1 General. Downdraft appliance ventilation system
- 518.2 Ventilation System. The downdraft appliance ventilation …
- 518.3 Fire-Extinguishing Equipment. For fire-extinguishing equ…
- 518.4 Airflow Switch or Transducer. An airflow switch or
- 518.5 Surface Materials. Any surface located directly
- 519.1 Where Required. Type II hoods shall be installed
- 519.2 Construction of Type II Hoods. Type II hoods
- 519.3 Type II Hood Exhaust System Net Airflow. The
- 519.4 Type II Exhaust Duct Systems. Ducts and
- 519.5 Termination of Type II Hood Exhaust System.
- 519.6 Makeup Air. Makeup air shall be provided in accordance w…
- 519.7 Independent Exhaust Duct System. Single or
- Chapter 6 — DUCT SYSTEMS
- Chapter 7 — COMBUSTION AIR
- Chapter 8 — CHIMNEYS AND VENTS
- Chapter 9 — INSTALLATION OF SPECIFIC APPLIANCES
- Chapter 10 — BOILERS AND PRESSURE VESSELS
- Chapter 11 — REFRIGERATION
- Chapter 12 — HYDRONICS
- Chapter 13 — FUEL GAS PIPING
- Chapter 14 — PROCESS PIPING
- Chapter 15 — SOLAR ENERGY SYSTEMS
- Chapter 16 — STATIONARY POWER PLANTS
- Chapter 17 — GEOTHERMAL ENERGY SYSTEMS AND AMBIENT TEMPERATURE…
- Chapter 18 — REFERENCED STANDARDS
- Appendix A — RESIDENTIAL PLAN EXAMINER REVIEW FORM FOR HVAC SY…
- Appendix B — PROCEDURES TO BE FOLLOWED TO PLACE GAS EQUIPMENT …
- Appendix C — INSTALLATION AND TESTING OF OIL (LIQUID) FUEL-FIR…
- Appendix D — FUEL SUPPLY: MANUFACTURED/MOBILE HOME PARKS AND R…
- Appendix E — SUSTAINABLE PRACTICES
- Appendix F — SIZING OF VENTING SYSTEMS AND OUTDOOR COMBUSTION …
- Appendix G — EXAMPLE CALCULATION OF OUTDOOR AIR RATE
- Appendix H — PROFESSIONAL QUALIFICATIONS
- Appendix I — INDOOR HORTICULTURAL FACILITIES
- Appendix J — CLEAN AIR DELIVERY