Chapter 1 Administration

Chapter 2 Definitions

Chapter 3 General Regulations

Chapter 4 Ventilation Air

Chapter 5 Exhaust Systems

Part I – Environmental Air Ducts and Product Conveying Systems

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 Referenced Standards

Appendices [PDF]

Appendix A Residential Plan Examiner Review Form for HVAC System Design

Appendix B Procedures to be Followed to Place Gas Equipment in Operation

Appendix C Installation and Testing of Oil (Liquid) Fuel-Fired Equipment

Appendix D Fuel Supply: Manufactured/Mobile Home Parks and Recreational Vehicle Parks

Appendix E Sustainable Practices

Appendix F Sizing of Venting Systems and Outdoor Combustion and Ventilation Opening Design

Appendix G Example Calculation of Outdoor Air Rate

This chapter includes requirements for environmental air ducts, product-conveying systems, and commercial hoods and kitchen ventilation. Part I addresses environmental air ducts and product conveying systems. Part II addresses commercial hoods and kitchen ventilation.
Exhaust openings terminating to the outdoors shall be covered with a corrosion-resistant screen having not less than 14 of an inch (6.4 mm) openings, and shall have not more than 12 of an inch (12.7 mm) openings.

Exception: Clothes dryers.
Exhaust ducts shall terminate in accordance with Section 502.2.1 through Section 502.2.3.
Environmental air duct exhaust shall terminate not less than 3 feet (914 mm) from a property line, 10 feet (3048 mm) from a forced air inlet, and 3 feet (914 mm) from openings into the building. Environmental exhaust ducts shall not discharge onto a public walkway.
Ducts conveying explosive or flammable vapors, fumes, or dusts shall terminate not less than 30 feet (9144 mm) from a property line, 10 feet (3048 mm) from openings into the building, 6 feet (1829 mm) from exterior walls or roofs, 30 feet (9144 mm) from combustible walls or openings into the building that are in the direction of the exhaust discharge, and 10 feet (3048 mm) above adjoining grade.

    Other product-conveying outlets shall terminate not less than 10 feet (3048 mm) from a property line, 3 feet (914 mm) from exterior walls or roofs, 10 feet (3048 mm) from openings into the building, and 10 feet (3048 mm) above adjoining grade.
Commercial kitchens exhaust ducts shall terminate in accordance with Section 510.9 or Section 510.10.

Part I – Environmental Air Ducts and Product Conveying Systems

Motors and fans shall be sized to provide the required air movement. Motors in areas that contain flammable vapors or dusts shall be of a type approved for such environments. A manually operated remote control installed at an approved location shall be provided to shut off fans or blowers in flammable vapor or dust systems. Equipment used in operations that generate explosive or flammable vapors, fumes, or dusts shall be interlocked with the ventilation system so that the equipment cannot be operated unless the ventilation fans are in operation. Motors for fans used to convey flammable vapors or dusts shall be located outside the duct or shall be protected with approved shields and dust-proofing. Where belts are used, they shall not enter the duct unless the belt and pulley within the duct are enclosed. Motors and fans shall be accessible for servicing and maintenance.
Parts of fans in contact with explosive or flammable vapors, fumes, or dusts shall be of nonferrous or nonsparking materials or their casing shall be lined or constructed of such material. Where the size and hardness of materials passing through a fan are capable of producing a spark, both the fan and the casing shall be of nonsparking materials. Where fans are required to be spark-resistant, their bearings shall not be within the airstream, and parts of the fan shall be grounded. Fans in systems handling materials that are likely to clog the blades, and fans in buffing or woodworking exhaust systems, shall be of the radial-blade or tube-axial type.

    Equipment used to exhaust explosive or flammable vapors, fumes, or dusts shall bear an identification plate stating the ventilation rate for which the system was designed.

    Fans located in systems conveying corrosives shall be of materials that are resistant to the corrosive or shall be coated with corrosion-resistant materials.
[BSC-CG], [DSA-SS & DSA-SS/CC] In mechanically ventilated buildings, provide regularly occupied areas of the building with air filtration media for outside and return air that provides at least a Minimum Efficiency Reporting Value (MERV) of 8. MERV 8 filters shall be installed prior to occupancy, and recommendations for maintenance with filters of the same value shall be included in the operation and maintenance manual in compliance with Chapter 5, Division 5.5. of the California Green Building Standards Code (CALGreen).

Exceptions:
  1. An ASHRAE 10-percent to 15-percent efficiency filter shall be permitted for an HVAC unit meeting the 2013 California Energy Code having 60,000 Btu/h (17.6 kW) or less capacity per fan coil, if the energy use of the air delivery system is 0.4 W/cfm [848 W/(m3/s)] or less at design air flow.
  2. Existing mechanical equipment.
Installed filters shall be clearly labeled by the manufacturer indicating the MERV rating.
Where not specified in this chapter, exhaust ducts shall be constructed and installed in accordance with Chapter 6 and shall be airtight as approved by the Authority Having Jurisdiction. Environmental air ducts that have an alternate function as a part of an approved smoke-control system do not require design as Class 1 product-conveying ducts.

Exceptions:
  1. Ductless range hoods where installed in accordance with the manufacturer's installation instructions.
  2. Condensing clothes dryers where installed in accordance with the manufacturer's installation instructions.
Exhaust ducts shall terminate outside the building and shall be equipped with backdraft dampers or with motorized dampers that automatically shut where the systems or spaces served are not in use. [OSHPD 1, 2 & 4] Exception: Backdraft dampers are not required when the exhaust fan must operate continuously.

Exception: Where the exhaust duct does not discharge into a common exhaust plenum and one of the following:
  1. The exhaust fan runs continuously.
  2. The exhaust duct serves space(s) that are not mechanically heated or cooled.
  3. The space served is maintained at positive pressure.
Single or combined mechanical exhaust systems shall be independent of other exhaust systems.
Ducts used for domestic kitchen range ventilation shall be of metal and shall have smooth interior surfaces.

Exception: Ducts for domestic kitchen downdraft grill-range ventilation installed under a concrete slab floor shall be permitted to be of approved Schedule 40 PVC provided:
  1. The under-floor trench in which the duct is installed shall be completely backfilled with sand or gravel.
  2. Not more than 1 inch (25.4 mm) of 6 inch diameter (152 mm) PVC coupling shall be permitted to protrude above the concrete floor surface.
  3. PVC pipe joints shall be solvent cemented to provide an air and greasetight duct.
  4. The duct shall terminate above grade outside the building and shall be equipped with a back-draft damper.
A clothes dryer exhaust duct shall not be connected to a vent connector, gas vent, chimney, and shall not terminate into a crawl space, attic, or other concealed space. Exhaust ducts shall not be assembled with screws or other fastening means that extend into the duct and that are capable of catching lint, and that reduce the efficiency of the exhaust system. Exhaust ducts shall be constructed of rigid metallic material. Transition ducts used to connect the dryer to the exhaust duct shall be listed for that application or installed in accordance with the clothes dryer manufacturer's installation instructions. Clothes dryer exhaust ducts shall terminate to the outside of the building in accordance with Section 502.2.1 and shall be equipped with a backdraft damper. Screens shall not be installed at the duct termination. Devices, such as fire or smoke dampers, that will obstruct the flow of the exhaust shall not be used. Where joining of ducts, the male end shall be inserted in the direction of airflow.
Makeup air shall be provided in accordance with the following:
  1. Makeup air shall be provided for Type 1 clothes dryers in accordance with the manufacturer's instructions. [NFPA 54:10.4.3.1]. Where a closet is designed for the installation of a clothes dryer, an opening of not less than 100 square inches (0.065 m2) for makeup air shall be provided in the door or by other approved means.
  2. Provision for makeup air shall be provided for Type 2 clothes dryers, with a free area of not less than 1 square inch (0.0006 m2) for each 1000 British thermal units per hour (Btu/h) (0.293 kW) total input rating of the dryer(s) installed. [NFPA 54:10.4.3.2]
Where a compartment or space for a Type 1 clothes dryer is provided, not less than a 4 inch diameter (102 mm) exhaust duct of approved material shall be installed in accordance with Section 504.0.

    Type 1 clothes dryer exhaust ducts shall be of rigid metal and shall have smooth interior surfaces. The diameter shall be not less than 4 inches nominal (100 mm) and the thickness shall be not less than 0.016 of an inch (0.406 mm).
Unless otherwise permitted or required by the dryer manufacturer's instructions and approved by the Authority Having Jurisdiction, domestic dryer moisture exhaust ducts shall not exceed a total combined horizontal and vertical length of 14 feet (4267 mm), including two 90 degree (1.57 rad) elbows. A length of 2 feet (610 mm) shall be deducted for each 90 degree (1.57 rad) elbow in excess of two.
Listed clothes dryer transition ducts not more than 6 feet (1829 mm) in length shall be permitted to be used to connect the Type 1 dryer to the exhaust ducts. Transition ducts and flexible clothes dryer transition ducts shall not be concealed within construction, and shall be installed in accordance with the manufacturer's installation instructions.
Commercial dryer exhaust ducts shall be installed in accordance with their listings. The installation of commercial clothes dryer exhaust ducts shall comply with the appliance manufacturer's installation instructions.
Exhaust ducts for Type 2 clothes dryers shall comply with the following:
  1. Exhaust ducts for Type 2 clothes dryers shall comply with Section 504.4. [NFPA 54:10.4.5.1]
  2. Exhaust ducts for Type 2 clothes dryers shall be constructed of sheet metal or other noncombustible material. Such ducts shall be equivalent in strength and corrosion resistance to ducts made of galvanized sheet steel not less than 0.0195 of an inch (0.4953 mm) thick. [NFPA 54:10.4.5.2]
  3. Type 2 clothes dryers shall be equipped or installed with lint-controlling means. [NFPA 54: 10.4.5.3]
  4. Exhaust ducts for Type 2 clothes dryers shall be installed with a clearance of not less than 6 inches (152 mm) from adjacent combustible material. Where exhaust ducts for Type 2 clothes dryers are installed with reduced clearances, the adjacent combustible material shall be protected in accordance with Table 303.10.1. [NFPA54:10.4.5.4]
  5. Where ducts pass through walls, floors, or partitions, the space around the duct shall be sealed with noncombustible material. [NFPA 54:10.4.5.5]
  6. Multiple installations of Type 2 clothes dryers shall be made in a manner to prevent adverse operation due to back pressures that are capable of being created in the exhaust systems. [NFPA 54: 10.4.5.6] The exhaust fan shall operate continuously or shall be interlocked to exhaust air where a clothes dryer is in operation.
Where permitted by the clothes dryer manufacturer's installation instructions, multiple clothes dryers shall be permitted to be installed with a common exhaust. The common exhaust duct shall be constructed of rigid metal and shall be installed in a fire-resistant rated enclosure in accordance with the building code. The duct material shall be of rigid metal with a thickness of not less than 0.020 of an inch (0.508 mm) (24 gauge). The duct enclosure shall be provided with a cleanout opening at the base of not less than 12 inches by 12 inches (305 mm by 305 mm). The exhaust fan shall be located downstream of branch connections and operated continuously and shall be monitored by an approved means.
Ducts shall be supported in accordance with SMACNA HVAC Duct Construction Standard - Metal and Flexible.
Heat (energy) recovery ventilators shall be installed in accordance with their listings and comply with the appliance manufacturer's installation instructions. Non-ducted heat recovery ventilators shall comply with UL 1815. Ducted heat recovery ventilators shall comply with UL 1812. Heat (energy) recovery ventilator ducts shall comply with Chapter 6.
Bathroom and laundry room exhaust ducts shall be permitted to be of gypsum wallboard subject to the limitations of Section 602.5.
A mechanical ventilation or exhaust system shall be installed to control, capture, and remove emissions generated from product use or handling where required in accordance with the building code or fire code and where such emissions result in a hazard to life or property. The design of the system shall be such that the emissions are confined to the area in which they are generated by air currents, hoods, or enclosures and shall be exhausted by a duct system to a safe location or treated by removing contaminants. Ducts conveying explosives or flammable vapors, fumes, or dusts shall extend directly to the exterior of the building without entering other spaces and shall not extend into or through ducts and plenums.

Exception: Ducts conveying vapor or fumes having flammable constituents less than 25 percent of their Lower Flammability Limit (LFL) shall be permitted to pass through other spaces.
Incompatible materials shall not be conveyed in the same exhaust system. [NFPA 91:4.1.2]
In systems conveying flammable vapors, gases, or mists, the concentration shall not exceed 25 percent of the lower flammability limit (LFL).

Exception: Higher concentrations shall be permitted where the exhaust system is designed and protected in accordance with the Standard on Explosion Prevention Systems in Chapter 17, using one or more of the following techniques:
  1. Combustible concentration reduction
  2. Oxidant concentration reduction
  3. Deflagration suppression
  4. Deflagration pressure containment [NFPA 91:4.1.3, 4.1.3.1]
    Contaminated air shall not be recirculated to occupied areas unless contaminants have been removed. Air contaminated with explosive or flammable vapors, fumes, or dusts; flammable or toxic gases; or radioactive material shall not be recirculated.
A mechanical ventilation system shall be interlocked to operate with the equipment used to produce vapors, fumes, or dusts that are flammable or hazardous.
Fire dampers shall not be installed where the material being exhausted is toxic and where a risk evaluation indicates that the toxic hazard is more than the fire hazard. Exhaust ducts shall not pass through fire walls. [NFPA 91:4.1.10, 4.1.11]
Product-conveying ducts shall be classified according to their use, as follows:
  1. Class 1 -   Ducts conveying nonabrasives, such as smoke, spray, mists, fogs, noncorrosive fumes and gases, light fine dusts, or powders.
  2. Class 2 -   Ducts conveying moderately abrasive particulate in light concentrations, such as sawdust and grain dust, and buffing and polishing dust.
  3. Class 3 -   Ducts conveying Class 2 materials in high concentrations and highly abrasive materials in low concentrations, such as manganese, steel chips, and coke.
  4. Class 4 -   Ducts conveying highly abrasive material in high concentrations.
  5. Class 5 -   Ducts conveying corrosives, such as acid vapors.
The velocity and circulation of air in work areas shall be such that contaminant's are captured by an airstream at the area where the emissions are generated and conveyed into a product-conveying duct system. Mixtures within work areas where contaminants are generated shall be diluted to be accordance with Section 505.1.2 with air that does not contain other contaminants. The velocity of air within the duct shall be not less than set forth in Table 505.4. Systems for removal of vapors, gases, and smoke shall be designed by the constant velocity or equal friction methods.

    Systems conveying particulate matter shall be designed by employing the constant velocity method. Systems conveying explosive or radioactive materials shall be pre-balanced through duct sizing. Other systems shall be permitted to be designed with balancing devices such as dampers. Dampers provided to balance airflow shall be provided with securely fixed minimum-position blocking devices to prevent restricting flow below the required volume or velocity.

TABLE 505.4
MINIMUM DUCT DESIGN VELOCITIES*
[NFPA 91: TABLE A.4.1.5]
NATURE OF CONTAMINANTS EXAMPLES FEET PER MINUTE
DESIGN VELOCITY
(feet per minute)
Vapors, gases, smoke Vapors, gases, and smoke Any
Fumes Welding 2000
Fine light dusts Cotton lint, wood flour, litho powder 2500
Dry Dusts and powders Fine rubber dust, molding powder dust,
jute lint, cotton dust, shavings(light), soap dust, leather shavings
3000
Average industrial dusts Grinding dust, buffing lint(dry), wool jute dust (shaker waste),
coffee beans, shoe dust, granite dust, silica flour, general material
handling, brick cutting, clay dust, foundry (general), limestone dust,
packaging and weighing asbestos dust in textile industries
3500
Heavy Dusts Sawdust (heavy and wet), metal turnings, foundry tumbling barrels,
and shake-out, sandblast dust, wood blocks, hog waste, brass
turning, cast-iron boring dust, lead dust
4000
Heavy or moist dusts Lead dust with chips, moist cement dust, asbestos chunks from
transite pipe cutting machines, buffing lint (sticky), quick-lime dust
4500
For SI units: 1 foot per minute = 0.005 m/s
*Systems that are handling combustible particulate solids shall be accordance with NFPA 654.
Makeup air shall be provided to replenish air exhausted by the ventilation system. Makeup air intakes shall be located so as to avoid recirculation of contaminated air within enclosures.
Hoods and enclosures shall be used where contaminants originate in a concentrated area. The design of the hood or enclosure shall be such that air currents created by the exhaust systems will capture the contaminants and transport them directly to the exhaust duct. The volume of air shall be sufficient to dilute explosive or flammable vapors, fumes, or dusts in accordance with Section 505.4. Hoods of steel shall have a base metal thickness not less than 0.027 of an inch (0.686 mm) (No. 22 gauge) for Class 1 and Class 5 metal duct systems; 0.033 of an inch (0.838 mm) (No. 20 gauge) for hoods serving a Class 2 duct system; 0.044 of an inch (1.118 mm) (No. 18 gauge) for hoods serving a Class 3 duct system; and 0.068 of an inch (1.727 mm) (No. 14 gauge) for hoods serving a Class 4 duct system.

    Approved nonmetallic hoods and duct systems shall be permitted to be used for Class 5 corrosive systems where the corrosive mixture is nonflammable. Metal hoods used with Class 5 duct systems shall be protected with an approved corrosion-resistant material. Edges of hoods shall be rounded. The minimum clearance between hoods and combustible construction shall be the clearance required by the duct system.
The pharmacy shall have a designated area for the preparation of sterile products for dispensing which shall be ventilated in a manner not interfering with laminar air flow.

Note: For additional pharmacy building standard requirements, see Chapter 12, California Building Code.
In all pharmacies preparing parenteral cytotoxic agents, all compounding shall be conducted within a certified Class II Type A or Class II Type B vertical laminar airflow hood with bag in - bag out design. The pharmacy must ensure that contaminated air plenums that are under positive air pressure are leak tight.

Note: For additional pharmacy building standard requirements, see Chapter 12, California Building Code.
Materials used in product-conveying duct systems shall be suitable for the intended use and shall be of metal.

Exceptions:
  1. Asbestos-cement, concrete, clay, or ceramic materials shall be permitted to be used where it is shown that these materials will be equivalent to metal ducts installed in accordance with this chapter.
  2. Ducts serving a Class 5 system shall be permitted to be constructed of approved nonmetallic material where the corrosive characteristics of the material being conveyed make a metal system unsuitable and where the mixture being conveyed is nonflammable.

        Approved nonmetallic material shall be either a listed product having a flame-spread index not exceeding 25 and a smoke-developed rating of 50 or less on both inside and outside surfaces without evidence of continued progressive combustion, or shall have a flame-spread index not exceeding 25 and shall be installed with an automatic fire-sprinkler protection system inside the duct.
  3. Ducts used in central vacuum cleaning systems within a dwelling unit shall be constructed of materials in accordance with the applicable standards referenced in Chapter 17. Penetrations of fire walls or floor-ceiling or roof-ceiling assemblies shall be in accordance with the building code.
    Copper or ferrous pipes or conduits extending from within the separation between a garage and dwelling unit to the central vacuuming unit shall be permitted to be used.

    Aluminum ducts shall not be used in systems conveying flammable vapors, fumes, or explosive dusts, nor in Class 2, 3, or 4 systems. Galvanized steel and aluminum ducts shall not be used where the temperature of the material being conveyed exceeds 400°F (204°C).

    Metal ducts used in Class 5 systems that are not resistant to the corrosiveness of the product shall be protected with an approved corrosion-resistant material.
Ducts used for conveying products shall be airtight construction as approved by the Authority Having Jurisdiction, and shall not have openings other than those required for operation and maintenance of the system. Ducts constructed of steel shall comply with Table 506.2(1) or Table 506.2(2).

Exceptions:
  1. Class 1 product-conveying ducts that operate at less than 4 inches water column (0.9 kPa) negative pressure and convey noncorrosive, nonflammable, and nonexplosive materials at temperatures not exceeding 250°F (121°C) shall be permitted to be constructed in accordance with SMACNA HVAC Duct Construction Standards-Metal and Flexible.
  2. Ducts used in central vacuuming systems within a dwelling unit shall be constructed of materials in accordance with the applicable standards referenced in Chapter 17. Penetrations of fire-resistive walls, or floor-ceiling or roof-ceiling assemblies shall be in accordance with the building code. Copper or ferrous pipes or conduit extending from within the separation between a garage and dwelling unit to the central vacuum unit shall be permitted to be used.

        The use of rectangular ducts conveying particulates shall be subject to approval of the Authority Having Jurisdiction. The design of rectangular ducts shall consider the adhesiveness and buildup of products being conveyed within the duct.

        Aluminum construction shall be permitted to be used in Class 1 duct systems. The thickness of aluminum ducts shall be not less than two Brown and Sharpe gauges thicker than the gauges required for steel ducts set forth in Table 506.2(1) and Table 506.2(2).

For SI units: 1 inch = 25.4 mm, 1 inch water column = 0.249 kPa


For SI units: 1 inch = 25.4 mm, 1 inch water column = 0.249 kPa
Fittings in Class 2, 3, and 4 systems shall be not less than two gauges thicker than the thickness required for straight runs. Flexible metallic duct shall be permitted to be used for connecting ductwork to vibrating equipment. Duct systems subject to wide temperature fluctuations shall be provided with expansion joints.

    Branches shall connect to main ducts at the large end of transitions at an angle not exceeding 45 degrees (0.79 rad).

    Except for ducts used to convey noncorrosive vapors with no particulate, accessible cleanouts shall be provided at 10 foot (3048 mm) intervals and at changes in direction. Access openings shall also be provided for access to sprinklers and other equipment within the duct that require servicing.
Ducts conveying explosive dusts shall have explosion vents, openings protected by anti-flashback swing valves, or rupture diaphragms. Openings to relieve explosive forces shall be located outside the building. Where relief devices cannot provide sufficient pressure relief, ductwork shall be designed to withstand an internal pressure of not less than 100 pounds-force per square inch (psi) (689 kPa).

    Where a room or building contains a dust explosion hazard that is external to protected equipment, as defined in NFPA 654, such areas shall be provided with deflagration venting to a safe outside location.
Supports shall be of noncombustible materials and the spacing shall not exceed 12 feet (3658 mm) for 8 inch (203 mm) ducts and 20 feet (6096 mm) for larger ducts.
Duct supports shall be designed to carry the weight of the duct half filled with material. Where sprinkler protection is provided or cleaning of duct will be performed, the hanger's design shall include the weight of the expected liquid accumulation. Duct supports shall be designed to prevent placing loads on connected equipment. [NFPA 91:4.5.1 - 4.5.3]

Exception: Where approved drainage is provided, the weight of the water shall not require consideration.
Hangers and supports exposed to corrosive atmospheres shall be corrosion resistant. [NFPA 91:4.5.4]
To prevent vibration and stress on the duct, hangers and supports shall be securely fastened to the building or structure. [NFPA 91:4.5.5]
Hangers and supports shall be designed to allow for expansion and contraction. [NFPA 91:4.5.6]
Sprinklers or other fire-protection devices shall be installed within ducts having a cross-sectional dimension exceeding 10 inches (254 mm) where the duct conveys flammable vapors or fumes. Sprinklers shall be installed at 12 foot (3658 mm) intervals in horizontal ducts and at changes in direction. In vertical runs, sprinklers shall be installed at the top and at alternate floor levels.
Ductwork and system components handling combustible material and operating at less than 140°F (60°C) shall have a clearance of not less than 18 inches (457 mm) from combustible construction or a combustible material. [NFPA 91:4.6.2]

Exceptions:
  1. Where the ductwork system is operating at less than 140°F (60°C) and is equipped with an approved automatic extinguishing system designed for the specific hazard, the clearance shall be permitted to be reduced to 6 inches (152 mm) from combustible materials and 12 of an inch (12.7 mm) from combustible construction. [NFPA 91:4.6.2.1]
  2. Where the combustible material and construction is protected by the use of materials or products listed for protection purposes or in accordance with Table 303.10.1.
Spacers and ties for protection materials shall be of noncombustible material and shall not be installed on the duct side of the protection system. [NFPA 91:4.6.4.2]
With clearance reduction systems using a ventilated airspace, air circulation shall be provided as described in Table 303.10.1. There shall be not less than 1 inch (25.4 mm) between the wall protector and combustible walls and ceilings for clearance, reduction systems using a ventilated space.
Mineral wool batts (blanket or board) shall have a density of not less than 8 pounds per cubic feet (lb/ft3) (128 kg/m3) and have a melting point of not less than 1500°F (816°C). [NFPA 91:4.6.4.3]
Insulation board used as a part of a clearance-reduction system shall have a thermal conductivity of 1 British thermal unit inch per hour square foot degree Fahrenheit [Btu•in/(h•ft2•°F)] [0.1 W/(m•K)] or less. Insulation board shall be formed of noncombustible material. [NFPA 91:4.6.4.4]
There shall be not less than 1 inch (25.4 mm) between the duct and the wall protector. In no case shall the clearance between the duct and the wall surface be reduced below that shown in Table 303.10.1.
Duct systems operating at elevated temperatures exceeding 140°F (60°C) shall have clearances from combustible building construction or combustible materials of not less than 18 inches (457 mm).
Where clearance is reduced by using an air gap between the combustible surface and the selected means of protection, air circulation shall be provided by one of the methods in accordance with Section 506.7.7.1 through Section 506.7.7.3. [NFPA 91:4.6.4.7]
Air circulation shall be permitted to be provided by leaving edges of the wall protecting system open with not less than a 1 inch (25.4 mm) air gap. [NFPA 91:4.6.4.7.1]
Where the means for protection is mounted on a single flat wall away from corners, air circulation shall be permitted to be provided by one of the following:
  1. Leaving the top and bottom edges open to circulation by maintaining the 1 inch (25.4 mm) air gap.
  2. Leaving the top and both side edges open to circulation by maintaining the 1 inch (25.4 mm) air gap. [NFPA 91:4.6.4.7.2]
Thermal shielding that covers two walls in a corner shall be permitted to be open at the top and bottom edges with not less than 1 inch (25.4 mm) air gap. [NFPA 91:4.6.4.7.3]
Ducts installed in locations where they are subject to physical damage shall be protected by guards.
Cooking equipment used in processes producing smoke or grease-laden vapors shall be equipped with an exhaust system that is in accordance with the equipment and performance requirements of this chapter. [NFPA 96:4.1.1] Such equipment and its performance shall be maintained in accordance with the requirements of this chapter during 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 (where 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 components at intervals necessary to maintain good working conditions as follows:
  1. Airflows shall be maintained. [NFPA 96:4.1.4]
  2. The responsibility for inspection, testing, maintenance, and cleanliness of the ventilation control and fire protection of the commercial cooking operations 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]
  3. Solid-fuel cooking equipment shall comply with the requirements of Section 517.0. [NFPA 96:4.1.6]
  4. 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]
  5. Interior surfaces of the exhaust system shall be accessible for cleaning and inspection purposes. [NFPA 96:4.1.8]
  6. Cooking equipment used in fixed, mobile, or temporary concessions, such as trucks, buses, trailers, pavilions, tents, or a form of roofed enclosure, shall be in accordance with this chapter unless otherwise exempted by the Authority Having Jurisdiction. [NFPA 96:4.1.9]
Penetrations shall be sealed with listed devices in accordance with the requirements of Section 507.2.1.
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 508.7. Seams, joints, and penetrations of the ductwork shall comply with Section 510.5.3.
Where enclosures are not required, hoods, grease removal devices, exhaust fans, and ducts shall have a clearance of not less than 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 ]
Where a hood, duct, or grease removal device is listed for clearances less than those in accordance with Section 507.3, the listing requirements shall be permitted. [NFPA 96:4.2.2]
Where a clearance reduction system consisting of 0.013 of an inch (0.33 mm) (28 gauge) sheet metal spaced out 1 inch (25.4 mm) on noncombustible spacers is provided, there shall be not less than 9 inches (229 mm) clearance to combustible material. [NFPA 96:4.2.3.1]
Where a clearance reduction system consisting of 0.027 of an inch (0.686 mm) (22 gauge) sheet metal on 1 inch (25.4 mm) mineral wool batts or ceramic fiber blanket reinforced with wire mesh or equivalent spaced out 1 inch (25.4 mm) on noncombustible spacers is provided, there shall be not less than 3 inches (76 mm) clearance to combustible material. [NFPA 96:4.2.3.2]
Where a clearance reduction system consisting of a listed and labeled field-applied grease duct enclosure material, system, product, or method of construction specifically evaluated for such purpose in accordance with ASTM E2336, the required clearance shall be in accordance with the listing. [NFPA 96:4.2.3.3]
Zero clearance to limited-combustible materials shall be permitted where protected by one of the following:
  1. Metal lath and plaster.
  2. Ceramic tile.
  3. Quarry tile.
  4. Other noncombustible materials or assembly of noncombustible materials that are listed for the purpose of reducing clearance.
  5. Other materials and products that are listed for the purpose of reducing clearance. [NFPA 96:4.2.3.4]
In the event of damage, the material or product shall be repaired and restored to meet its intended listing or clearance requirements and shall be approved by the Authority Having Jurisdiction. [NFPA 96:4.2.4.1]
In the event of a fire within a kitchen exhaust system, the duct and its enclosure (rated shaft, factory-built grease duct enclosure, or field-applied grease duct enclosure) shall be inspected by qualified personnel to determine whether the duct and protection method are structurally sound, capable of maintaining their fire protection function, and in accordance with this chapter for continued operation. [NFPA 96:4.2.4.2]
Protection shall be provided on the wall from the bottom of the hood to the floor, or to the top of the noncombustible material extending to the floor, to the same level as required in Section 507.3. [NfPA 96:4.2.4.3]
The protection methods for ducts to reduce clearance shall be applied to the combustible or limited-combustible construction, not to the duct itself. [NFPA 96:4.2.4.4]
Factory-built grease duct enclosures shall be protected with a through-penetration firestop system classified in accordance with ASTM E814 or UL 1479 having an "F" and "T" rating equal to the fire resistance rating of the assembly being penetrated from the point at which the duct penetrates a ceiling, wall, or floor to the outlet terminal. The factory-built grease duct protection system shall be listed in accordance with UL 2221. The factory-built grease duct protection system shall be installed in accordance with the manufacturer's installation instructions and the listing requirements. [NFPA 96:4.3.3]
Field-applied grease duct enclosures shall be protected with a through penetration firestop system classified in accordance with ASTM E814 or UL 1479 having an "F" and "T" rating equal to the fire resistance rating of the assembly being penetrated. The surface of the field fabricated grease duct shall be continuously covered on sides from the point at which the duct enclosure penetrates a ceiling, wall, or floor to the outlet terminal. The field-applied grease duct shall be listed in accordance with ASTM E2336 and installed in accordance with the manufacturer's installation instructions and the listing requirements. [NFPA 96:4.3.1]
Field-applied grease duct enclosures and factory-built grease duct enclosures shall demonstrate that they provide mechanical and structural integrity, resiliency, and stability where subjected to expected building environmental conditions, duct movement under general operating conditions, and duct movement due to fire conditions. [NFPA 96:4.3.4]
Measures shall be taken to prevent physical damage to a material or product used for the purpose of reducing clearances.

Exception: Where the duct is protected with a field-applied grease duct enclosure or factory-built grease duct enclosure.
The specifications of material, gauge, and construction of the duct used in the testing and listing of field-applied grease duct enclosures and factory-built grease duct enclosures shall be included as minimum requirements in their listing and installation documentation. [NFPA 96:4.3.5]
The following clearance options for which field-applied grease duct enclosures and factory-built grease duct enclosures have been successfully evaluated shall be clearly identified in their listing and installation documentation and on their labels:
  1. Open combustible construction clearance at manufacturer's requested dimensions.
  2. Closed combustible construction clearance at manufacturer's requested dimensions, with or without specified ventilation.
  3. Rated shaft clearance at manufacturer's requested dimensions, with or without specified ventilation. [NFPA 96:4.3.6]
A duct shall be permitted to contact noncombustible floors, interior walls, and other noncombustible structures or supports, but it shall not be in contact for more than 50 percent of its surface area for each lineal foot of contact length. [NFPA 96:4.4.1]
Where duct contact must exceed the requirements of Section 507.3.7, the duct shall be protected from corrosion. [NFPA 96:4.4.2]
Where the duct is listed for zero clearance to combustibles or otherwise protected with a material or product listed for the purpose of reducing clearance to zero, the duct shall be permitted to exceed the contact limits of Section 507.3.7 without additional corrosion protection. [NFPA 96:4.4.3]
Clearances between the duct and interior surfaces of enclosures shall be in accordance with the requirements of Section 507.3. [NFPA 96:4.5]
A drawing(s) of the exhaust system installation along with a copy of operating instructions for subassemblies and components used in the exhaust system, including electrical schematics, shall be on the premises. [NFPA 96:4.6]
Where required by the Authority Having Jurisdiction, notification in writing shall be given of an alteration, replacement, or relocation of an exhaust, extinguishing system or part thereof or cooking equipment. [NFPA 96:4.7]

    Satisfaction shall be provided to the Authority Having JuJisdiction that the complete exhaust system as addressed in this chapter is installed and operable in accordance with the approved design and the manufacturer's installation instructions.
Type I hoods shall be installed at or above commercial-type deep-fat fryers, broilers, grills, hot-top ranges, ovens, barbecues, rotisseries, and similar equipment that emits comparable amounts of smoke or grease in a food-processing establishment. For the purpose of this section, a food-processing establishment shall include a building or portion thereof used for the processing of food, but shall not include a dwelling unit. Type II hoods shall be installed above equipment and dishwashers that generate steam, heat, and products of combustion, and where grease or smoke is not present.

Exceptions:
  1. Cooking appliance that is in accordance with UL 710B for reduced emissions where the grease discharge does not exceed 2.9 E-09 ounces per cubic inch (oz/in3) (5.0 E-06 kg/m3) where operated with a total airflow of 500 cubic feet per minute (cfm) (0.236 m3/s).
  2. Recirculating systems listed in accordance with UL 710B and installed in accordance with Section 516.0.
  3. Dishwashing machines connected to a Type II duct system and exhausted directly to the outdoors.
  4. Dishwashing machines with a self-contained condensing system listed in accordance with UL 921 and installed in a space where the HVAC system has been engineered to accommodate the latent and sensible heat load emitted from such appliances as approved by the Authority Having Jurisdiction. Such equipment shall be provided with an interlocking device to prevent opening of the appliance prior to completion of its cycle.
Listed hood assemblies shall be installed in accordance with the terms of their listing and the manufacturer's installation instructions. Listed hood assemblies shall be tested in accordance with UL 710. [NFPA 96:5.4]
Listed ultraviolet hoods shall be installed and maintained in accordance with the terms of their listing and the manufacturer's installation instructions. Duct systems connected to ultraviolet hoods shall comply with Section 510.0. Ultraviolet hoods shall be tested and listed in accordance with UL 710 and UL 710C. [NFPA 96:5.5]
Listed exhaust hoods with or without exhaust dampers shall be permitted to be constructed of materials required by the listing. [NFPA 96:5.1.6]
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]
The hood or that portion of a primary collection means designed for collecting cooking vapors and residues constructed of steel shall be not less than 0.048 of an inch (1.219 mm) (No. 18 MSG), 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.
Type II hoods constructed of steel shall be not less than 0.024 of an inch (0.61 mm) (No. 24 gauge). Hoods constructed of copper shall be of copper sheets weighing not less than 0.17 ounces per square inch (oz/in2) (7.47 kg/m2). Joints and seams shall be substantially tight. Solder shall not be used except for sealing a joint or seam.
Hoods shall be secured in place [OSHPD 1, 2 & 4] to resist the lateral loads given in the California Building Code, Title 24, Part 2 by noncombustible supports. The supports shall be capable of supporting the expected weight of the hood and plus 800 pounds (362.9 kg).
Wall-mounted exhaust hood assemblies shall be tight fitting against the back wall 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]
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]
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]
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 508.8. [NFPA 96:5.1.8.1]
FIGURE 508.8
TYPICAL SECTION OF EYEBROW-TYPE HOOD
[NFPA 96: FIGURE5.1.8.1]
The duct connecting 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]
Insulation materials other than electrical insulation shall have a flame spread index of not more than 25, where tested in accordance with ASTM E84 or UL 723. Adhesives or cements used in the installation of insulating materials shall be in accordance with this section where tested with the specific insulating material [NFPA 96:5.1.9, 5.1.10]
Hoods shall be sized in accordance with the airflow capacity in accordance with Section 508.10.1.1 and installed to provide for the removal of heat, and capture and removal of grease-laden vapors in accordance with Section 511.2.2.
For canopy type commercial cooking hoods, the inside edge thereof shall overhang or extend a horizontal distance of not less than 6 inches (152 mm) beyond the edge of the cooking surface on open sides, and the vertical distance between the lip of the hood and the cooking surface shall not exceed 4 feet (1219 mm).

Exception: Listed exhaust hoods are to be installed in accordance with the terms of their listings and the manufacturer's installation instructions.
Canopy-type commercial cooking hoods shall exhaust through the hood with a quantity of air not less than determined by the application in accordance with Section 508.10.1.2 through Section 508.10.1.6. The exhaust quantity shall be the net exhaust from the hood determined in accordance with Equation 508.10.1.1. The duty level for the hood shall be the duty level of the appliance that has the highest (heaviest) duty level of appliances installed underneath the hood.

Exception: Listed exhaust hoods installed in accordance with the manufacturer's installation instructions.

ENET = EHOOD - MAID (Equation 508.10.1.1)

Where:
ENET = net hood exhaust
EHOOD = total hood exhaust
MAID = makeup air, internal discharge
The minimum net airflow for hoods used for solid fuel cooking appliances such as charcoal, briquette, and mesquite to provide the heat source for cooking shall be in accordance with Table 508.10.1.2.
TABLE 508.10.1.2
EXTRA-HEAVY-DUTY COOKING APPLIANCE AIRFLOW
TYPE OF HOOD AIRFLOW (cubic foot per minute
per linear foot of hood)
Backshelf/pass-over Not permitted
Double island canopy (per side) 550
Eyebrow Not permitted
Single island canopy 700
Wall-mounted canopy 550
For SI units: 1 cubic foot per minute = 0.00047 m3/s, 1 foot = 25.4 mm
The minimum net airflow for hoods used for cooking appliances such as gas under-fired broilers, gas chain (conveyor) broilers, electric and gas wok ranges, and electric and gas over-fired (upright) broilers shall be in accordance with Table 508.10.1.3.

TABLE 508.10.1.3
HEAVY-DUTY COOKING APPLIANCE AIRFLOW
TYPE OF HOOD AIRFLOW (cubic foot per minute
per linear foot of hood)
Backshelf/pass-over 400
Double island canopy (per side) 400
Eyebrow Not permitted
Single island canopy 600
Wall-mounted canopy 400
For SI units: 1 cubic foot per minute = 0.00047 m3/s, 1 foot = 25.4 mm
The minimum net airflow for hoods used for cooking appliances such as electric and gas hot-top ranges, gas open-burner ranges (with or without oven), electric and gas flat griddles, electric and gas double sided griddles, electric and gas fryers (including open deep fat fryers, donut fryers, kettle fryers, and pressure fryers), and electric and gas conveyor pizza ovens shall be in accordance with Table 508.10.1.4.
TABLE 508.10.1.4
MEDIUM-DUTY COOKING APPLIANCE AIRFLOW
TYPE OF HOOD AIRFLOW (cubic foot per minute
per linear foot of hood)
Backshelf/pass-over 300
Double island canopy (per side) 300
Eyebrow 250
Single island canopy 500
Wall-mounted canopy 300
For SI units: 1 cubic foot per minute = 0.00047 m3/s, 1 foot = 25.4 mm
The minimum net airflow for hoods used for cooking appliances such as gas and electric ovens (including standard, bake, roasting, revolving, retherm, convection, combination convection/steamer, rotisserie, countertop conveyorized baking/finishing, deck, and pastry), discrete element ranges (with or without oven), electric and gas steam-jacketed kettles less than 20 gallons (76 L), electric and gas pasta cookers, electric and gas compartment steamers (both pressure and atmospheric), electric and gas cheesemelters, electric and gas tilting skillets (braising pans) electric and gas rotisseries, and electric and gas salamanders shall be in accordance with Table 508.10.1.5.

TABLE 508.10.1.5
LlGHT-DUTY COOKING APPLIANCE AIRFLOW
TYPE OF HOOD AIRFLOW (cubic foot per minute
per linear foot of hood)
Backshelf/pass-over 250
Double island canopy (per side) 250
Eyebrow 250
Single island canopy 400
Wall-mounted canopy 200
For SI units: 1 cubic foot per minute = 0.00047 m3/s, 1 foot = 25.4 mm
The net airflow for Type II hoods used for dish washing equipment shall be not less than 200 cubic feet per minute (0.094 m3/s) per linear foot (m) of hood length.
Noncanopy-type commercial cooking hoods shall be installed and sized in accordance with the manufacturer's installation instructions, and Section 508.10.2.1 and Section 508.10.2.2.

Exception: Listed hood assemblies designed and installed specifically for the intended use.
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).
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 [(ft3/min)/ft)] [0.464 (m3/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.
Type I hoods shall bear a label indicating the exhaust flow rate in cubic feet per minute per lineal foot [(m3/s)/m].
The construction and size of exhaust hood assemblies with integrated supply air plenums shall be in accordance with the requirements of Section 508.1 through Section 508.10. [NFPA 96:5.3.1]
The construction of the outer shell or the inner exhaust shell shall be in accordance with Section 508.1 through Section 508.9. [NFPA 96:5.3.2]
Where the outer shell is welded, the inner shell shall be of greasetight construction. [NFPA 96:5.3.3]
A fire-actuated damper shall be installed in the supply air plenum at each point where a supply air duct inlet or a supply air outlet penetrates the continuously welded shell of the assembly. [NFPA 96:5.3.4.1]
The fire damper shall be listed for such use or be part of a listed exhaust hood with or without exhaust damper. [NFPA 96:5.3.4.2]
The actuation device shall have a temperature rating not to exceed 286°F (141°C). [NFPA 96:5.3.4.3]
Supply air plenums that discharge air from the face rather than from the bottom or into the exhaust hood and that are isolated from the exhaust hood by the continuously welded shell extending to the lower outermost perimeter of the entire hood assembly shall not require a fire-actuated damper. [NFPA 96:5.3.4.4]
Where solid-fuel cooking equipment is to be used, the solid-fuel hood assembly shall be in accordance with Section 517.0.
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.
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. [NFPA 96:6.1.1, 6.1.2]
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]
The distance between the grease removal device and the cooking surface shall be not less than 18 inches (457 mm). [NFPA 96:6.2.1.1]
Where grease removal devices are used in conjunction with charcoal or charcoal-type broilers, including gas or electrically heated charbroilers, a vertical distance of not less than 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 509.2 and Section 509.2.1, the listing requirements shall be permitted. [NFPA 96:6.2.1.4]
  3. Grease removal devices supplied as part of listed hood assemblies shall be installed in accordance with the terms of the listing and the manufacturer's installation instructions. [NFPA 96:6.2.1.5]
Where the distance between the grease removal device and the appliance flue outlet (heat source) is less than 18 inches (457 mm), grease removal devices shall be protected from combustion gas outlets and from direct flame impingement occurring during normal operation of cooking appliances producing high flue gas temperatures. [NFPA 96:6.2.2.1]
This protection shall be permitted to be accomplished by the installation of a steel or stainless steel baffle plate between the heat source and the grease removal device. [NFPA 96:6.2.2.2]
The baffle plate shall be sized and located so that flames or combustion gases shall travel a distance not less than 18 inches (457 mm) from the heat source to the grease removal device. [NFPA 96:6.2.2.3]
The baffle shall be located not less than 6 inches (152 mm) from the grease removal devices. [NFPA 96:6.2.2.4]
Grease filters shall be listed and constructed of steel or other non-combustible material, and shall be of rigid construction that will not distort or crush under normal operation, handling, cleaning, or replacement. [SFM] For applications listed in Section 1.11.0 regulated by the Office of the State Fire Marshal, grease filters shall be Class 1 when tested in accordance with the test method in Title 24, Part 12, Chapter 12-71, SFM Standard 12-71-1.
Grease filters shall be arranged so that exhaust air passes through the grease filters. [NFPA 96:6.2.3.4]
Grease filters shall be easily accessible for removal. [NFPA 96:6.2.3.5]
Grease filters shall be installed at an angle not less than 45 degrees (0.79 rad) from the horizontal. [NFPA 96:6.2.3.6]
[DPH] Grease filters shall be Class 1 when tested in accordance with the test method in SFM 12-71-1.
Grease filters shall be equipped with a grease drip tray beneath their lower edges. [NFPA 96:6.2.4.1]
Grease drip trays shall be kept to the minimum size needed to collect grease and shall be pitched to drain into an enclosed metal container having a capacity not exceeding 1 gallon (4 L). [NFPA 96:6.2.4.2, 6.2.4.3]
Grease filters that require a specific orientation to drain grease shall be clearly so designated, or the hood shall be constructed so that filters cannot be installed in the wrong orientation. [NFPA 96:6.2.5]
Where solid-fuel cooking equipment is provided with grease removal devices, these devices shall be in accordance with Section 517.0.
Ducts shall not pass through fire walls. [NFPA 96:7.1.1]
Ducts shall lead as directly to the exterior of the building, so as not to unduly increase a fire hazard. [NFPA 96:7.1.2]
Duct systems shall not be interconnected with a building ventilation or exhaust system. [NFPA 96:7.1.3]
Ducts shall be installed with not less than 2 percent slope on horizontal runs up to 75 feet (22860 mm) and not less than 8 percent slope on horizontal runs more than 75 feet (22860 mm). Factory-built grease ducts shall be permitted to be installed in accordance with the listing and the manufacturer's installation instructions. Horizontal ducts shall be provided with access in accordance with Section 510.3.3.

    Drains shall be provided at low points in horizontal ducts. Where provided, drains shall be continuously welded to the exhaust duct or listed grease duct drains in accordance with the terms of the listing and the manufacturer's installation instructions.

    Ducts shall be installed without forming dips or traps. In manifold (common duct) systems, the lowest end of the main duct shall be connected flush on the bottom with the branch duct. [NFPA 96:7.1.4 - 7.1.4.5]
Openings required for accessibility shall be in accordance with Section 510.3 through Section 510.3.2. [NFPA 96:7.1.5]
A sign shall be placed on access panels stating the following:

ACCESS PANEL - DO NOT OBSTRUCT [NFPA 96:7.1.6]
Duct bracing and supports shall be of noncombustible material, securely attached to the structure and designed to carry gravity and lateral loads within the stress limitations of the building code. Bolts, screws, rivets, and other mechanical fasteners shall not penetrate duct walls.
Ducts and plenums serving Type II hoods shall be constructed of rigid metallic materials in accordance with Chapter 6. Duct bracing and supports shall comply with Chapter 6. Ducts subject to positive pressure shall be adequately sealed.
Listed grease ducts shall be installed in accordance with the terms of their listings and manufacturer's installation instructions. [NFPA 96:7.1.7]
Clearance between ducts and combustible materials shall be provided in accordance with the requirements of Section 507.3. [NFPA 96:7.2]
Openings shall be provided at the sides or at the top of the duct, whichever is more accessible, and at changes of direction. Openings shall be protected by approved access constructed and installed in accordance with the requirements of Section 510.3.7. [NFPA 96:7.3.1, 7.3.2]

Exception: Openings shall not be required in portions of the duct that are accessible from the duct entry or discharge. [NFPA 96:7.3.3]
For hoods with dampers in the exhaust or supply collar. an access panel for cleaning and inspection shall be provided in the duct or the hood within 18 inches (457 mm) of the damper. [NFPA 96:7.3.4]

Exception: Dampers that are accessible from under the hood.
Exhaust fans with ductwork connected to both sides shall have access for cleaning and inspection within 3 feet (914 mm) of each side of the fan. Wall-mounted exhaust fans shall have access for cleaning and inspection within 3 feet (914 mm) of the exhaust fan. [NFPA 96:7.3.7, 7.3.8]
On horizontal ducts, not less than one 20 inch by 20 inch (508 mm by 508 mm) opening shall be provided for personnel entry. [NFPA 96:7.4.1.1]
Where an opening of the size specified in Section 510.3.3 is not possible, openings large enough to permit thorough cleaning shall be provided at 12 feet (3658 mm) intervals. [NFPA 96:7.4.1.2]
Where not easily accessible from a 10 foot (3048 mm) stepladder, openings on horizontal grease duct systems shall be provided with safe access and a work platform. [NFPA 96:7.4.1.3]
Support systems for horizontal grease duct systems 24 inches (610 mm) and larger in a cross-sectional dimension shall be designed for the weight of the ductwork plus 800 pounds (362.9 kg) at a point in the duct systems. [NFPA 96:7.4.1.4]
On vertical ductwork where personnel entry is possible, access shall be provided at the top of the vertical riser to accommodate descent. [NFPA 96:7.4.2.1]
Where personnel entry is not possible, an access for cleaning shall be provided on each floor. [NFPA 96:7.4.2.2]
Where not easily accessible from a 10 foot (3048 mm) stepladder, openings on vertical grease ducts shall be provided with safe access and a work platform. [NFPA 96:7.4.2.3]
On nonlisted ductwork, the edge of the opening shall be not less than 112 inches (38 mm) from all outside edges of the duct or welded seams. [NFPA 96:7.4.1.5]
Access panels shall be of the same material and thickness as the duct. Access panels shall have a gasket or sealant that is rated for 1500°F (816°C) and shall be greasetight. Fasteners, such as bolts, weld studs, latches, or wing nuts, used to secure the access panels shall be carbon steel or stainless steel and shall not penetrate duct walls.

Exception: Listed grease duct access door assemblies (access panels) shall be installed in accordance with the terms of the listings and the manufacturer's installation instructions. [NFPA 96:7.4.3]
Where openings are located in ducts within an enclosure, the access panel including its components shall be of the same fire rating as the enclosure.
Openings for installation, servicing, and inspection of listed fire protection system devices and for duct cleaning shall be provided in ducts and enclosures and shall be in accordance with the requirements of Section 510.3 through Section 510.3.2 and Section 510.7.7. Enclosure openings required to reach access panels in the ductwork shall be large enough for removal of the access panel through the enclosure opening. [NFPA 96:7.4.4]
Listed grease ducts shall be installed in accordance with the terms of the listing and the manufacturer's installation instructions. [NFPA 96:7.1.7]
Factory-built grease ducts in accordance with UL 1978 shall be permitted to incorporate non-welded joints in accordance with their listings.
Other grease ducts shall comply with the requirements of Section 510.5.1 through Section 510.5.5. [NFPA 96:7.5]
Ducts shall be constructed of and supported by carbon steel not less than 0.060 of an inch (1.524 mm) (No. 16 MSG) in thickness or stainless steel not less than 0.048 of an inch (1.219 mm) (No. 18 MSG) in thickness. [NFPA 96:7.5.1.1]
Factory-built grease ducts listed in accordance with UL 1978 shall be permitted to use materials in accordance with their listing. [NFPA 96:7.5.1.2]
Seams, joints, penetrations, and duct-to-hood collar connections shall have a liquid-tight continuous external weld. [NFPA 96:7.5.2.1]

Exceptions:
  1. Factory-built grease duct listed in accordance with UL 1978 shall be permitted to incorporate nonwelded joint construction in accordance with their listing. [NFPA 96:7.5.2.1.1]
  2. Duct-to-hood collar connections as shown in Figure 510.5.3 shall not require a liquid-tight continuous external weld. [NFPA 96:7.5.2.2]
  3. Penetrations shall be permitted to be sealed by other listed devices that are tested to be greasetight and are evaluated under the same conditions of fire severity as the hood or enclosure of listed grease extractors and whose presence does not detract from the hood or the duct's structural integrity. [NFPA 96:7.5.2.3]
  4. Internal welding shall be permitted, provided the joint is formed or ground smooth and is readily accessible for inspection. [NFPA 96:7.5.2.4]


For SI units: 1 inch = 25.4 mm, °C = (°F-32)/1.8
FIGURE 510.5.3
PERMITTED DUCT-TO HOOD COLLAR CONNECTION
[NFPA 96: FIGURE 7.5.2.2]
Prior to the use of or concealment of a portion of a grease duct system, a leakage test shall be performed to determine that all welded joints and seams are liquid tight. [NFPA 96:7.5.2.1.2]
Duet-to-duct connection shall be as follows:
  1. Telescoping joint, as shown in Figure 510.5.3.2(1).
  2. Bell-type joint, as shown in Figure 510.5.3.2(2).
  3. Flange with edge weld, as shown in Figure 510.5.3.2(3).
  4. Flange with filled weld, as shown in Figure 510.5.3.2(4). [NFPA 96:7.5.5.1]
For SI units: 1 inch = 25.4 mm

Notes:
  1. Duct size decreases (going upward) with each telescope.
  2. Smaller (inside) duct section shall be above or uphill (on sloped duct), to be self draining into larger (outside) duct.
FIGURE 510.5.3.2(1)
TELESCOPING-TYPE DUCT CONNECTION
[NFPA 96: FIGURE 7.5.5.1(a)]

For SI units: 1 inch = 25.4 mm

Notes:
  1. Duct size stays the same throughout the duct system.
  2. Smaller (inside) male duct end is always above or uphill (on sloped duct), to be self-draining into larger (outside) female duct end.
FIGURE 510.5.3.2(2)
BELL-TYPE DUCT CONNECTION
[NFPA 96: FIGURE 7.5.5.1(b)]


FIGURE 510.5.3.2(3)
FLANGE WITH EDGE WELD DUCT CONNECTION
[NFPA 96: FIGURE 7.5.5.1(c)]


FIGURE 510.5.3.2(4)
FLANGE WITH FILLED WELD DUCT CONNECTION
[NFPA 96: FIGURE 7.5.5.1(d)]
Butt welded connections shall not be permitted. [NFPA 96:7.5.5.2]
For telescoping and bell-type connections, the inside duct section shall be uphill of the outside duct section. [NFPA 96:7.5.5.3]
Prior to the use of or concealment of a grease duct system, a leakage test shall be performed to determine that welded joints and seams are liquid tight. The leakage test shall consist of a light test, water pressure test, or an approved equivalent test. The permit holder shall be responsible for providing the necessary equipment and for performing the test. Such test shall be conducted in accordance with ASHRAE 154.
The exterior portion of the ductwork shall be vertical where possible and shall be installed and supported on the exterior of a building. Bolts, screws, rivets, and other mechanical fasteners shall not penetrate duct walls. Clearance of a duct shall be in accordance with Section 507.3. [NFPA 96:7.6.1 - 7.6.3]
Ducts shall be protected on the exterior by paint or other suitable weather-protective coating. Ducts constructed of stainless steel shall not be required to have additional paint or weather-protective coatings. Ductwork subject to corrosion shall have minimal contact with the building surface. [NFPA 96:7.6.4 - 7.6.6]
In buildings more than one story in height, and in one-story buildings where the roof-ceiling assembly is required to have a fire resistance rating, the ducts shall be enclosed in a continuous enclosure extending from the lowest fire-rated ceiling or floor above the hood, through concealed spaces, to or through the roof, to maintain the integrity of the fire separations required by the applicable building code provisions. The enclosure shall be sealed around the duct at the point of penetration of the first fire-rated barrier after the hood, to maintain the fire resistance rating of the enclosure. The enclosure shall be vented to the exterior of the building through weather-protected openings. [NFPA 96:7.7.1.2 - 7.7.1.4]

Exception: The continuous enclosure provisions shall not be required where a field-applied grease duct enclosure or a factory-built grease duct enclosure (see Section 507.3.4 through Section 507.3.6) is protected with a listed duct-through-penetration protection system equivalent to the fire resistance rating of the assembly being penetrated, and where the materials are installed in accordance with the conditions of the listings and the manufacturer's installation instructions and are acceptable to the Authority Having Jurisdiction. [NFPA 96:7.7.1.5]
Buildings less than four stories in height shall have an enclosure with a fire resistance rating of not less than 1 hour. [NFPA 96:7.7.2.1.1]
Buildings four stories or more in height shall have an enclosure with a fire resistance rating of not less than 2 hours. [NFPA 96:7.7.2.1.2]
Clearance from the duct or the exhaust fan to the interior surface of enclosures of combustible construction shall be not less than 18 inches (457 mm), and clearance from the duct to the interior surface of enclosures of noncombustible or limited-combustible construction shall be not less than 6 inches (152 mm). Provisions for reducing clearances as described in Section 507.3 through Section 507.3.3.3 shall not be applicable to enclosures. [NFPA 96:7.7.2.2.1 -7.7.2.2.3]

Exception: Clearance from the outer surfaces of field-applied grease duct enclosures and factory-built grease duct enclosures to the interior surfaces of construction installed around them shall be permitted to be reduced where the field-applied grease duct enclosure materials and the factory-built grease duct enclosures are installed in accordance with the conditions of the listings and the manufacturer's installation instructions and are acceptable to the Authority Having Jurisdiction. [NFPA 96:7.7.2.2.4]
Field-applied grease duct enclosures and factory-built grease duct enclosures shall provide mechanical and structural integrity, resiliency, and stability where subjected to expected building environmental conditions, duct movement under general operating conditions, and duct movement as a result of interior and exterior fire conditions. [NFPA 96:7.7.2.2.5]
For field-applied grease duct enclosures and factory-built grease duct enclosures, the materials and products shall be provided in accordance with Section 510.7.5.1 and Section 510.7.5.2.
Measures shall be taken to prevent physical damage to a covering or enclosure material. Damage to the covering or enclosure shall be repaired, and the covering or enclosure shall be restored in accordance with its intended listing and fire-resistance rating, and be acceptable to the Authority Having Jurisdiction. [NFPA 96:7.7.3.1, 7.7.3.2]
In the event of a fire within a kitchen exhaust system, the duct, the enclosure, and the covering directly applied to the duct shall be inspected by qualified personnel to determine whether the duct, the enclosure, and the covering directly applied to the duct arc structurally sound, capable of maintaining their fire protection functions, approved for continued operation, and acceptable to the Authority Having Jurisdiction. [NFPA 96:7.7.3.3]
For listed grease ducts, see Section 510.4.
Where openings in the enclosure walls are provided, they shall be protected by listed fire doors of proper rating. Fire doors shall be installed in accordance with NFPA 80. Openings on other listed materials or products shall be clearly identified and labeled according to the terms of the listing and the manufacturer's instructions and shall be acceptable to the Authority Having Jurisdiction. [NFPA 96:7.7.4.1 - 7.7.4.3] The fire door shall be readily accessible, aligned and of a size to allow access to the rated access panels on the ductwork. [NFPA 96:7.7.4.4]
A duct system shall constitute an individual system serving exhaust hoods in one fire zone on one floor. Multiple ducts shall not be permitted in a single enclosure unless acceptable to the Authority Having Jurisdiction. [NFPA 96:7.7.5]
Grease ducts installed underground shall be approved for underground installation. The material of the grease duct shall be corrosion-resistant and shall comply with Section 510.5.1.
The grease duct shall be sloped to drain the grease back to an approved grease collection device. A grease collection device shall be located at the base of the vertical riser.
For horizontal installations, cleanouts for cleaning and maintenance shall be provided 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.
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 in accordance with Section 510.9.1, or through a wall in accordance with Section 510.9.2. [NFPA 96:7.8.1]
Rooftop terminations shall be arranged with or provided with the following:
  1. Not less than 10 feet (3048 mm) of horizontal clearance from the outlet to adjacent buildings, property lines, and air intakes.
  2. Not less than 5 feet (1524 mm) of horizontal clearance from the outlet (fan housing) to a combustible structure.
  3. A vertical separation of 3 feet (914 mm) below an exhaust outlet for air intakes within 10 feet (3048 mm) of the exhaust outlet.
  4. The ability to drain grease out of 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 a fan.
  6. A listed grease collection system that is in accordance with Section 510.9.1(4) and Section 510.9.1(5).
  7. A listed grease duct in accordance with Section 507.3.7 or ductwork in accordance with Section 507.3.8.
  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:

    1. Where the fan attaches to the ductwork, the ductwork is not less than 18 inches (457 mm) away from the roof surface, as shown in Figure 510.9.1.
    2. The fan discharges not less than 40 inches (1016 mm) away from the roof surface, as shown in Figure 510.9.1.
  9. Other approved fan, provided it is in accordance with the following criteria:

    1. The fan is in accordance with the requirements of Section 510.9.1(3) and Section 511.1.3.
    2. Its discharge or its extended duct discharge is in accordance with the requirements of Section 510.9.1(2). (See Section 511.1.3)
    3. 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]
Listed flexible connectors shall be permitted to be used on exterior roof locations where required for proper equipment vibration isolation.
Fans shall be provided with safe access and a work surface for inspection and cleaning. [NFPA 96:7.8.2.2]
Wall terminations shall be arranged with or provided with the following properties:
  1. Through a noncombustible wall with not less than 10 feet (3048 mm) of clearance from the outlet to adjacent buildings, property lines, grade level, combustible construction, electrical equipment or lines, and the closest point of an air intake or operable door or window at or below the plane of the exhaust termination. The closest point of an air intake or operable door or window above the plane of the exhaust termination shall be not less than 10 feet (3048 mm) in distance, plus 3 inches (76 mm) for each 1 degree (0.017 rad) from horizontal, the angle of degree being measured from the center of the exhaust termination to the center of the air intake, operable door or window, as indicated in Figure 510.9.2.

    Exception: A wall termination in a secured area shall be permitted to be at a lower height above grade where acceptable to the Authority Having Jurisdiction.
  2. The exhaust flow shall be directed perpendicularly outward from the wall face or upward.
  3. The ductwork shall be pitched to drain the grease back into the hood(s) or with a drain provided to bring the grease back into a container within the building or into a remote grease trap.
  4. A listed grease duct shall comply with Section 510.3.3 through Section 510.3.7; other ducts shall comply with Section 510.5.
  5. An approved fan shall comply with the requirements of Section 510.9.2(3), and Section 511.1.1 or Section 511.1.3. [NFPA 96:7.8.3]
For SI units: 1 inch = 25.4 mm, 1 foot = 304.8 mm
Notes:
  1. Fresh air intake (FAI) applies to an air intake, including an operable door or window.
  2. Example:
    FAI is same plane as exhaust or lower: 10 feet (min.) between closet edges.
    FAI above plane of exhaust: 10 feet + 3 inches.
FIGURE 510.9.2
EXHAUST TERMINATION DISTANCE FROM FRESH AIR INTAKE
(FAI) OR OPERABLE DOOR OR WINDOW
[NFPA 96: FIGURE 7.8.3]
The exhaust system shall terminate as follows:
  1. Rooftop terminations shall terminate not less than 10 feet (3048 mm) from a property line and the exhaust flow shall be directed away from the roof surface of the roof not less than 40 inches (1016 mm).
  2. Horizontal terminations shall terminate not less than 10 feet (3048 mm) from adjacent buildings, property lines, operable openings, and from grade level.
  3. The termination outlet shall not be directed onto a public way.
Where solid-fuel cooking equipment is to be vented, the duct system shall be in accordance with Section 517.0.
Exhaust fans shall be installed in accordance with Section 511.1.1 through Section 511.1.6. Exhaust fans shall comply with UL 762 and be installed in accordance with the manufacturer's installation instructions.
Upblast fans with motors surrounded by the airstream shall be hinged and supplied with flexible weatherproof electrical cable, and service hold-open retainers. Installation shall comply with the requirements of Section 510.9. Upblast fans shall have a drain directed to a readily accessible and visible grease receptacle not to exceed 1 gallon (4 L). [NFPA 96:8.1.2]
In-line fans shall be of the type with the motor located outside the airstream and with belts and pulleys protected from the airstream by a greasetight housing. In-Iine fans shall be connected to the exhaust duct by flanges securely bolted as shown in Figure 511.1.2(1) through Figure 511.1.2(4), or by a system specifically listed for such use. Flexible connectors shall not be used. [NFPA 96:8.1.3.1 - 8.1.3.3]

For SI units: 1 inch = 25.4 mm, °C = (°F-32)/1.8
FIGURE 511.1.2(1)
TYPICAL SECTION OF DUCT-TO-FAN
CONNECTION-BUTT JOINT METHOD
[NFPA 96: FIGURE 8.1.3.2(a)]


For SI units: 1 inch = 25.4 mm, °C = (°F-32)/1.8
FIGURE 511.1.2(2)
TYPICAL SECTION OF DUCT-TO-FAN
CONNECTION-OVERLAPPING METHOD
[NFPA 96: FIGURE 8.1.3.2(b)]


For SI units: 1 inch = 25.4 mm, °C = (°F-32)/1.8
FIGURE 511.1.2(3)
TYPICAL SECTION OF DUCT-TO-FAN
CONNECTION-SEALANT METHOD
[NFPA 96: FIGURE 8.1.3.2(c)]


For SI units: 1 inch = 25.4 mm, °C = (°F-32)/1.8
FIGURE 511.1.2(4)
TYPICAL SECTION OF DUCT-TO-FAN CONNECTION-DIRECT
TO FAN INLET CONE METHOD
[NFPA 96: FIGURE 8.1.3.2(d)]
Where the design or positioning of the fan allows grease to be trapped, a drain directed to a readily accessible and visible grease receptacle, not exceeding 1 gallon (4 L), shall be provided. In-line exhaust fans shall be located in an easily accessible area or approved size to allow for service or removal. Where the duct system connected to the fan is in an enclosure, the space or room in which the exhaust fan is located shall have the same fire resistance rating as the enclosure. [NFPA 96:8.1.3.4 - 8.1.3.6]
Utility set exhaust fans shall be installed in accordance with Section 511.1.3.1 through Section 511.1.3.3.
Fans installed at the rooftop termination point shall be in accordance with the following:
  1. Section 510.9.1 and Section 510.9.1.2.
  2. Flexible connectors shall be permitted.
  3. A drain shall be directed to a readily accessible and visible grease receptacle not to exceed 1 gallon (4 L).
Fans installed within the building shall be in accordance with the following:
  1. Located in an accessible area of a size to allow for service or removal [NFPA 96:8.1.4.2]
  2. Flexible connectors shall be prohibited. [NFPA 96:8.1.4.5]
  3. A drain shall be directed to a readily accessible and visible grease receptacle not to exceed 1 gallon (4 L). [NFPA 96:8.1.4.6]
Duct systems connected to fans in an enclosure shall be in accordance with the following:
  1. The space or room in which the exhaust fan is located shall have the same fire resistance rating as the enclosure.
  2. The fan shall be connected to the exhaust duct by flanges securely bolted as shown in Figure 511.1.2(1) through Figure 511.1.2(4) or by a system specifically listed for such use. [NFPA 96:8.1.4.3, 8.1.4.4]
Exhaust fan housings shall be constructed of carbon steel not less than 0.060 of an inch (1.524 mm) (No. 16 MSG) in thickness, of stainless steel not less than 0.048 of an inch (1.219 mm) (No. 18 MSG) in thickness, or, where listed, in accordance with the terms of the listing. [NFPA 96:8.1.5]
Openings for cleaning, servicing. and inspection shall be in accordance with the requirements of Section 510.3.2. Clearances shall be in accordance with the requirements of Section 507.3, or Section 510.7.3 and Section 510.7.4 where installed within an enclosure. [NFPA 96:8.1.6.1, 8.1.6.2]
Wiring and electrical equipment shall comply with California Electrical Code.
The air velocity through a duct shall be not less than 500 feet per minute (ft/min) (2.54 m/s) and not exceed 2500 ft/min (12.7 m/s).
Transition duct sections that do not exceed 3 feet (914 mm) in length and do not contain grease traps shall be permitted to be connected to hoods and exhaust fans that do not meet this velocity. [NFPA 96:8.2.1.2]
Exhaust air volumes for hoods shall be of sufficient level to provide for capture and removal of grease-laden cooking vapors. Test data, performance tests approved by the Authority Having Jurisdiction, or both shall be displayed, provided on request, or both. [NFPA 96:8.2.2.1, 8.2.2.2] Lower exhaust air volumes shall be permitted during no-load and partial load cooking conditions, provided they are sufficient to capture and remove flue gases and cooking effluent from cooking equipment.
A performance test shall be conducted upon completion and before final approval of the installation of a ventilation system serving commercial cooking appliances. The test shall verify the rate of exhaust airflow in accordance with Section 508.10.1.2 through Section 508.10.1.5. The permit holder shall furnish the necessary test equipment and devices required to perform the tests. [ASHRAE 154:4.8.1]
The permit holder shall verify capture and containment performance of the hoods. A field test shall be conducted with the appliance under the hood at operating temperatures, with the source of outdoor air providing makeup air for the hood operating and with the source of recirculated air providing conditioning for the space in which the hood operating is located. Capture and containment shall be verified visually by observing smoke or steam produced by actual or simulated cooking using devices such as smoke candles or smoke puffers. Smoke bombs shall not be used. [ASHRAE 154:4.8.2]
A hood exhaust fan(s) shall continue to operate after the extinguishing system has been activated, unless fan shutdown is required by a listed component of the ventilation system, or by the design of the extinguishing system. The hood exhaust fan shall not be required to start upon activation of the extinguishing system where the exhaust fan and cooking equipment served by the fan have been shut down. The exhaust fan shall be provided with a means so that the fan is activated when an appliance under the hood is turned on. [NFPA 96:8.2.3]
The makeup air quantity shall prevent negative pressures in the commercial cooking area(s) from exceeding 0.02 inch water column (0.005 kPa). Where the fire-extinguishing system activates, makeup air supplied internally to a hood shall be shut off.

    For compensating hoods, where a Type I or Type II hood has an internal discharge of makeup air, the makeup air flow shall not exceed 10 percent of the exhaust airflow, the exhaust airflow shall be the net exhaust from the hood in accordance with Section 508.10.1.2 through Section 50S.10.1.5. The total hood exhaust shall be determined in accordance with Equation 511.3.

ENET = EHOOD - MAID (Equation 511.3)

Where:
ENET = net hood exhaust
EHOOD = total hood exhaust
MAID = makeup air, internal discharge
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.
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]
The bleed-air ducts shall connect to the top or side of the master exhaust duct. [NFPA 96:8.4.2]
The bleed-air duct shall have a fire damper not less than 12 inches (305 mm) from the exhaust duct connection. [NFPA 96:8.4.3]
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 not less than 12 inches (305 mm) on both sides of the fire damper. [NFPA 96:8.4.4]
Each bleed air duct shall have a means of adjusting (e.g., using volume dampers) the bleed air quantity. [NFPA 96:8.4.5]
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]
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]
Unused tenant exhaust connections 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]
Where solid-fuel cooking equipment is used, exhaust and replacement air also shall be in accordance with Section 517.0.
Dampers shall not be installed in exhaust ducts or exhaust duct systems. [NFPA 96:9.1.1]
Where specifically listed for such use or where required as part of a listed device or system, dampers in exhaust ducts or exhaust duct systems shall be permitted. [NFPA 96:9.1.2]
Wiring systems shall not be installed in ducts. [NFPA 96:9.2.1]
Motors, lights, and other electrical devices shall be permitted to be installed in ducts or hoods or to be located in the path of travel of exhaust products were specifically listed for such use. [NFPA 96:9.2.2]
Lighting units in hoods shall not be located in concealed spaces except as permitted by Section 512.2.3 and Section 512.2.4. [NFPA 96:9.2.3.2]
Lighting units shall be permitted in concealed spaces where such units are part of a listed exhaust hood. [NFPA 96:9.2.3.3]
Listed lighting units specifically listed for such use and installed in accordance with the terms of the listing shall be permitted to be installed in concealed spaces. [NFPA 96:9.2.3.4]
Electrical equipment shall be installed in accordance with the California Electrical Code, with due regard to the effects of heat, vapor, and grease on the equipment.
Fume incinerators, thermal recovery units, air pollution control devices, or other devices shall be permitted to be installed in ducts, hoods or to be located in the path of travel of exhaust products where specifically listed for such use. Downgrading other parts of the exhaust system due to the installation of these approved devices, whether listed or not, shall not be permitted. [NFPA 96:9.3.1, 9.3.2]
An equipment, listed or otherwise, that provides secondary filtration or air pollution control and that is installed in the path of travel of exhaust products shall be provided with an approved automatic fire-extinguishing system, installed in accordance with fire-extinguishing system manufacturer's installation instructions, for the protection of the component sections of the equipment, and shall include protection of the ductwork downstream of the equipment, whether or not the equipment is provided with a damper. Filter media used in secondary filtration or air pollution control units and not in accordance with Section 509.2.3 shall have fire protection that is adequate for the filter media being used in accordance with the fire-extinguishing system manufacturer's installation instructions. Where the equipment provides a source of ignition, it shall be provided with a detection to operate the fire-extinguishing system protecting the equipment. [NFPA 96:9.3.3 - 9.3.4]
Where a cooking exhaust system employs an air pollution control device that recirculates air into the building, the requirements of Section 516.0 shall apply. [NFPA 96:9.3.5]
Where solid fuel cooking comprises a part of a cooking operation, additional provisions and equipment as described in Section 517.0 shall be used where required.
Fire-extinguishing equipment for the protection of grease removal devices, hood exhaust plenums, and exhaust duct systems shall be provided. [NFPA 96:10.1.1]
Cooking equipment that produces grease-laden vapors and is capable of being a source of ignition of grease in the hood, grease removal device, or duct shall be protected by fire-extinguishing equipment. [NFPA 96:10.1.2]
Fire-extinguishing equipment shall include both automatic fire-extinguishing systems as primary protection and portable fire extinguishers as secondary backup. [NFPA 96:10.2.1]
A placard shall be conspicuously placed near the fire extinguisher that states that the fire protection system shall be activated prior to using the fire-extinguisher. [NFPA 96:10.2.2]
Commercial cooking equipment that produce grease laden vapors shall be provided with a Type I Hood, in accordance with this Code, and an automatic fire extinguishing system that is listed and labeled for its intended use as follows:
  1. Wet chemical extinguishing system (NFPA 17A, Standard for Wet Chemical Extinguishing Systems), complying with UL 300, Fire Testing of Fire Extinguishing Systems for Protection of Restaurant Cooking Equipment. All existing dry chemical and wet chemical extinguishing systems shall comply with UL 300, Fire Testing of Fire Extinguishing Systems for Protection of Restaurant Cooking Equipment.
  2. Carbon dioxide extinguishing systems (NFPA 12, Standard on Carbon Dioxide Extinguishing Systems).
  3. Automatic fire sprinkler systems (NFPA 13, Standard for the Installation of Sprinkler Systems).
All existing dry chemical and wet chemical extinguishing systems shall comply with UL 300, no later than the second required servicing of the system following the effective date of this section.

Exceptions:
  1. Automatic fire-extinguishing equipment provided as part of listed recirculating systems in accordance with UL 710B. [NFPA 96:10.2.5]
  2. [DSA-SS and DSA-SS/CC] Public schools kitchens, without deep-fat fryers, shall be upgraded to a UL 300, Fire Testing of Fire Extinguishing Systems for Protection of Restaurant Cooking Equipment, compliant system during state funded modernization projects that are under the jurisdiction of the Division of the State Architect.
An abandoned pipe or conduit from a previous installation shall be removed from within the hood, plenum, and exhaust duct. [NFPA 96:10.2.7.1]
Penetrations and holes resulting from the removal of conduit or piping shall be sealed with listed or equivalent liquid-tight sealing devices. [NFPA 96:10.2.7.2]
The addition of obstructions to spray patterns from the cooking appliance nozzle(s) such as baffle plates, shelves, or a modification shall not be permitted. [NFPA 96:10.2.7.3]
Changes or modifications to the hazard after installation of the fire-extinguishing systems shall result in re-evaluation of the system design by a properly trained, qualified, and certified person(s). [NFPA 96:10.2.7.4]
Grease removal devices, hood exhaust plenums, and exhaust ducts requiring protection in accordance with Section 513.1 shall be permitted to be protected by a listed fixed baffle hood containing a constant or fire-actuated water wash system that is listed and in accordance with UL 300 or other equivalent standards and shall be installed in accordance with the requirements of their listing. [NFPA 96:10.2.8.1]
The water for listed, fixed baffle hood assemblies shall be permitted to be supplied from the domestic water supply where the minimum water pressure and flow are provided in accordance with the terms of the listing. [NFPA 96:10.2.8.3]
The water supply shall be controlled by a supervised water supply control valve. [NFPA 96:10.2.8.4]
The water wash in the fixed baffle hood specifically listed to extinguish a fire shall be activated by the cooking equipment extinguishing system. [NFPA 96:10.2.8.5]
A water-wash system approved to be used for protection of the grease removal device(s), hood exhaust plenum(s), exhaust duct(s), or combination thereof shall include instruction and electrical interface for simultaneous activation of the water-wash system from an automatic fire-extinguishing system, where the automatic fire-extinguishing system is used for cooking equipment protection. [NFPA 96:10.2.8.6]
Where the fire-extinguishing system provides protection for the cooking equipment, hood, and duct, activation of the water-wash shall not be required. [NFPA 96:10.2.8.7]
The water required for listed automatic fire-extinguishing systems shall be permitted to be supplied from the domestic water supply where the minimum water pressure and flow are provided in accordance with the terms of the listing. The water supply shall be controlled by a supervised water supply control valve. Where the water supply is from a dedicated fire protection water supply in a building with one or more fire sprinkler systems, separate indicating control valves and drains shall be provided and arranged so that the hood system and sprinkler system are capable of being controlled individually. [NFPA 96:10.2.9]
Valves controlling the water supply to listed fixed baffle hood assemblies, automatic fire-extinguishing systems, or both shall be listed indicating type of valve and shall be supervised open by one of the following methods:
  1. Central station, proprietary, or remote station alarm service.
  2. Local alarm service that will cause the sounding of an audible signal at a constantly attended point.
  3. Locking valves open.
  4. Sealing of valves and approved weekly recorded inspection. [NFPA 96:10.2.10]
Fixed pipe extinguishing systems in a single hazard area shall be arranged for simultaneous automatic operation upon actuation of any one of the systems. [NFPA 96:10.3.1]
Simultaneous operation shall not be required where the one fixed pipe extinguishing system is an automatic sprinkler system. Where an automatic sprinkler system is used in conjunction with a water-based fire-extinguishing system served by the same water supply, hydraulic calculations shall consider both systems operating simultaneously. [NFPA 96:10.3.2, 10.3.2.1]
Simultaneous operation shall be required where a dry or wet chemical system is used to protect common exhaust ductwork by NFPA 17A, Wet Chemical Extinguishing Systems.
Upon activation of a fire-extinguishing system for a cooking operation, sources of fuel and electric power that produce heat to equipment requiring protection by that system shall automatically shut off. [NFPA 96:10.4.1]

Exception: Solid-fuel cooking operations.
Steam supplied from an external source shall not be required to automatically shut off. [NFPA 96:10.4.2]
A gas appliance not requiring protection, but located under ventilating equipment where protected appliances are located, shall be automatically shut off upon activation of the extinguishing system. [NFPA 96:10.4.3]
Shutoff devices shall require manual reset. [NFPA 96:10.4.4]
A readily accessible means for manual activation shall be located between 42 inches and 48 inches (1067 mm and 1219 mm) above the floor, be accessible in the event of a fire, be located in a path of egress, and clearly identify the hazard protected. Not less than one manual actuation device shall be located not less than 10 feet (3048 mm) and not more than 20 feet (6096 mm) from the protected exhaust system(s) within the path of egress or at an alternative location acceptable to the Authority Having Jurisdiction. Manual actuation using a cable-operated pull station shall not require more than 40 pounds-force (lbf) (178 N) of force, with a pull movement not to exceed 14 inches (356 mm) to activate the automatic fire extinguishing system. The automatic and manual means of system activation external to the control head or releasing device shall be separate and independent of each other so that failure of one will not impair the operation of the other except as permitted in Section 513.5.1. [NFPA 96:10.5.1 - 10.5.2]
The manual means of system activation shall be permitted to be common with the automatic means where the manual activation device is located between the control head or releasing device and the first fusible link. [NFPA 96:10.5.3]
An automatic sprinkler system shall not require a manual means of system activation. [NFPA 96:10.5.4]
The means for manual activation shall be mechanical or rely on electrical power for activation in accordance with Section 513.5.4. [NFPA 96:10.5.5]
Electrical power shall be permitted to be used for manual activation where a standby power supply is provided or where supervision is provided in accordance with Section 513.7. [NFPA 96:10.5.6]
Upon activation of an automatic fire-extinguishing system, an audible alarm or visual indicator shall be provided to show that the system has activated. [NFPA 96:10.6.1]
Where a fire alarm signaling system is serving the occupancy where the extinguishing system is located, the activation of the automatic fire-extinguishing system shall activate the fire alarm signaling system. [NFPA 96:10.6.2]
Where electrical power is required to operate the fixed automatic fire-extinguishing system, the system shall be provided with a reserve power supply and be monitored by a supervisory alarm except as permitted in accordance with Section 513.7.1. [NFPA 96:10.7.1]
Where a fixed automatic fire-extinguishing system includes automatic mechanical detection and actuation as a backup detection system, electrical power monitoring and reserve power supply shall not be required. [NFPA 96:10.7.2]
System supervision shall not be required where a fire-extinguishing system(s) is interconnected or interlocked with the cooking equipment power source(s) so that where the fire-extinguishing system becomes inoperable due to power failure, sources of fuel or electric power that produce heat to cooking equipment serviced by that hood shall automatically shut off. [NFPA 96:10.7.3]
System supervision shall not be required where an automatic fire-extinguishing system, including automatic mechanical detection and actuation, is electrically connected to a listed fire-actuated water-wash system for simultaneous operation of both systems. [NFPA 96:10.7.4]
Hoods containing automatic fire-extinguishing systems are protected areas; therefore, these hoods are not considered obstructions to overhead sprinkler systems and shall not require floor coverage underneath. [NFPA 96:10.8.1]
A single detection device, listed with the extinguishing system, shall be permitted for more than one appliance where installed in accordance with the terms of the listing. [NFPA 96:10.8.2]
Where required, complete drawings of the system installation, including the hood(s), exhaust duct(s), and appliances, along with the interface of the fire-extinguishing system detectors, piping, nozzles, fuel and electric power shutoff devices, agent storage container(s), and manual actuation device(s), shall be submitted to the Authority Having Jurisdiction. [NFPA 96:10.9.1]
Installation of systems shall be performed by persons properly trained and qualified to install the specific system being provided. The installer shall provide certification to the Authority Having Jurisdiction that the installation is in agreement with the terms of the listing and the manufacturer's installation instructions, approved design, or both. [NFPA 96:10.9.2]
Portable fire extinguishers shall be selected and installed in kitchen cooking areas in accordance with Chapter 3, Title 19 California Code of Regulations and shall be specifically listed for such use. Class K fire extinguishers shall be provided for cooking appliances hazards that involve combustible cooking media such as vegetable oils, animal oils, and fats.
Portable fire extinguishers shall be provided for other hazards in kitchen areas and shall be selected and installed in accordance with Chapter 3, Title 19 California Code of Regulations.
Portable fire extinguishers shall be maintained in accordance with NFPA 10. [NFPA 96:10.10.4]
Portable fire extinguishers listed specifically for use in the kitchen cooking areas shall also be permitted.
Where solid-fuel cooking equipment is served by fire extinguishing equipment, the provisions of Section 517.0 shall apply.
Exhaust systems shall be operated where cooking equipment is turned on. [NFPA 96:11.1.1]
Filter-equipped exhaust systems shall not be operated with filters removed. [NFPA 96:11.1.2]
Openings provided for replacing air exhausted through ventilating equipment shall not be restricted by covers, dampers, or other means that would reduce the operating efficiency of the exhaust system. [NFPA 96:11.1.3]
Instructions for manually operating the fire-extinguishing system shall be posted conspicuously in the kitchen and shall be reviewed with employees by the management. [NFPA 96:11.1.4]
Listed exhaust hoods shall be operated in accordance with the terms of their listings and the manufacturer's instructions. [NFPA 96:11.1.5]
Cooking equipment shall not be operated while its fire-extinguishing system or exhaust system is nonoperational or impaired. [NFPA 96:11.1.6]
Secondary filtration and pollution control equipment shall be operated in accordance with the terms of its listing and the manufacturer's instructions. [NFPA 96:11.1.7]
Inspection and maintenance of "other equipment" as allowed in Section 512.3 shall be conducted by trained and qualified persons at a frequency determined by the manufacturer's instructions or the equipment listing. [NFPA 96:11.1.8]
Maintenance of the fire-extinguishing systems and listed exhaust hoods containing a constant or fire-activated water system that is listed to extinguish a fire in the grease removal devices, hood exhaust plenums, and exhaust ducts shall be made by trained, qualified, and certified person(s) acceptable to the Authority Having Jurisdiction not less than every 6 months. [NFPA 96:11.2.1]
Actuation and control components, including remote manual pull stations, mechanical and electrical devices, detectors, and actuators shall be tested for proper operation during the inspection in accordance with the manufacturer's instructions. The specific inspection and maintenance requirements of the extinguishing system standards as well as the applicable installation and maintenance manuals for the listed system and service bulletins shall be followed. [NFPA 96:11.2.2, 11.2.3]
Fusible links of the metal alloy type and automatic sprinklers of the metal alloy type shall be replaced not less than semiannually except as permitted by Section 514.2.3 and Section 514.2.4. [NFPA 96:11.2.4]
The year of manufacture and the date of installation of the fusible links shall be marked on the system inspection tag. The tag shall be signed or initialed by the installer.

    Detection devices that are bulb-type automatic sprinklers and fusible links other than the metal alloy type shall be examined and cleaned or replaced annually. [NFPA 96:11.2.5. 11.2.5.1, 11.2.6]
Fixed temperature-sensing elements other than the fusible metal alloy type shall be permitted to remain continuously in service, provided they are inspected and cleaned, or replaced where necessary in accordance with the manufacturer's instructions every 12 months or more frequently to ensure operation of the system. [NFPA 96:11.2.7]
Where required, certificates of inspection and maintenance shall be forwarded to the Authority Having Jurisdiction. [NFPA 96:11.2.8]
The entire exhaust system shall be inspected for grease buildup by a trained, qualified, and certified person(s) acceptable to the Authority Having Jurisdiction and in accordance with Table 514.3. [NFPA 96:11.4]

TABLE 514.3
SCHEDULE OF INSPECTION FOR GREASE BUILDUP
[NFPA 96: TABLE 11.4]
TYPE OR VOLUME OF COOKING INSPECTION
FREQUENCY
Systems serving solid-fuel cooking operations. Monthly
Systems serving high-volume cooking operations
such as 24-hour cooking, charbroiling, or
wok cooking.
Quarterly
Systems serving moderate-volume cooking
operations.
Semiannually
Systems serving low-volume cooking operations,
such as churches, day camps, seasonal
businesses, or senior centers.
Annually
Where, upon inspection, the exhaust system is found to be contaminated with deposits from grease-laden vapors, the contaminated portions of the exhaust system shall be cleaned by a trained, qualified, and certified person(s) acceptable to the Authority Having Jurisdiction. [NFPA 96:11.6.1]
Hoods, grease removal devices, fans, ducts, and other appurtenances shall be cleaned to remove combustible contaminants prior to surfaces becoming heavily contaminated with grease or oily sludge. [NFPA 96:11.6.2]
At the start of the cleaning process, electrical switches that could be activated accidentally shall be locked out. [NFPA 96:11.6.3]
Components of the fire suppression system shall not be rendered inoperable during the cleaning process. [NFPA 96:11.6.4]
Fire-extinguishing systems shall be permitted to be rendered inoperable during the cleaning process where serviced by trained and qualified persons. [NFPA 96:11.6.5]
Flammable solvents or other flammable cleaning aids shall not be used. [NFPA 96:11.6.6]
Cleaning chemicals shall not be applied on fusible links or other detection devices of the automatic extinguishing system. [NFPA 96:11.6.7]
After the exhaust system is cleaned, it shall not be coated with powder or other substance. [NFPA 96:11.6.8]
Where cleaning procedures are completed, access panels (doors) and cover plates shall be restored to their normal operational condition. [NFPA 96:11.6.9]
Where an access panel is removed, a service company label or tag preprinted with the name of the company and giving the date of inspection or cleaning shall be affixed near the affected access panels. [NFPA 96:11.6.10]
Dampers and diffusers shall be positioned for proper airflow. [NFPA 96:11.6.11]
Where an exhaust cleaning service is used, a certificate showing the name of the servicing company, the name of the person performing the work, and the date of inspection or cleaning shall be maintained on the premises. [NFPA 96:11.6.13]
After cleaning or inspection is completed, the exhaust cleaning company and the person performing the work at the location shall provide the owner of the system with a written report that also specifies areas that were inaccessible or not cleaned. [NFPA 96:11.6.14]
Where required, certificates of inspection and cleaning and reports of areas not cleaned shall be submitted to the Authority Having Jurisdiction. [NFPA 96:11.6.15]
Where cleaning procedures are completed, electrical switches and system components shall be returned to an operable state. [NFPA 96:11.6.12]
Inspection and servicing of the cooking equipment shall be made not less than annually by properly trained and qualified persons. [NFPA 96:11.7.1]
Cooking equipment that collects grease below the surface, behind the equipment, or in cooking equipment flue gas exhaust, such as griddles or charbroilers, shall be inspected and, where found with grease accumulation, cleaned by a properly trained, qualified, and certified person acceptable to the Authority Having Jurisdiction. [NFPA 96:11.7.2]
Cooking equipment shall be approved based on one of the following criteria:
  1. Listings by a testing laboratory.
  2. Test data acceptable to the Authority Having Jurisdiction. [NFPA 96:12.1.1]
Listed appliances shall be installed in accordance with the terms of their listings and the manufacturer's installation instructions. Solid fuel used for flavoring within a gas-operated appliance shall be in a solid fuel holder (smoker box) that is listed with the equipment. [NFPA 96:12.1.2.1, 12.1.2.1.1]
Cooking appliances requiring protection shall not be moved, modified, or rearranged without prior re-evaluation of the fire-extinguishing system by the system installer or servicing agent, unless otherwise allowed by the design of the fire-extinguishing system. A solid fuel holder shall not be added to an existing appliance until the fire-extinguishing system has been evaluated by the fire-extinguishing system service provider. [NFPA 96:12.1.2.2, 12.1.2.2.1]
The fire-extinguishing system shall not require re-evaluation where the cooking appliances are moved for the purpose of maintenance and cleaning, provided the appliances are returned to approved design location prior to cooking operations, and disconnected fire-extinguishing system nozzles attached to the appliances are reconnected in accordance with the manufacturer's instructions and listing. [NFPA 96:12.1.2.3]
Deep-fat fryers shall be installed with not less than a 16 inch (406 mm) space between the fryer and surface flames from adjacent cooking equipment. [NFPA 96:12.1.2.4]
Where a steel or tempered glass baffle plate is installed not less than 8 inches (203 mm) in height between the fryer and surface flames of the adjacent appliance, the requirement for a 16 inch (406 mm) space shall not apply. [NFPA 96:12.1.2.5]
Where the fryer and the surface flames are at different horizontal planes, a height of not less than 8 inches (203 mm) shall be measured from the higher of the two. [NFPA 96:12.1.2.5.1]
Deep-fat fryers shall be equipped with a separate high-limit control in addition to the adjustable operating control (thermostat) to shut off fuel or energy where the fat temperature reaches 475°F (246°C) at 1 inch (25.4 mm) below the surface. [NFPA 96:12.2]
Recirculating systems containing or for use with appliances used in processes producing smoke or grease-laden vapors shall be equipped with components in accordance with the following:
  1. The clearance requirements of Section 507.3.
  2. The hood shall comply with the requirements of Section 508.0.
  3. Grease removal devices shall comply with Section 509.0.
  4. The air movement requirements of Section 511.2.1 and Section 511.2.2.
  5. Auxiliary equipment (such as particulate and odor removal devices) shall comply with Section 512.0.
  6. Fire-extinguishing equipment shall comply with the requirements of Section 513.0.

    Exception: Fire-extinguishing equipment in accordance with Section 513.1 and Section 513.5.
  7. The use and maintenance requirements of Section 514.0.
  8. The minimum safety requirements of Section 515.0.
  9. The requirements of Section 516.0. [NFPA 96:13.1]
  10. Provisions shall be provided for latent heat and excessive moisture acceptable to the Authority Having Jurisdiction.
Recirculating systems shall comply with Section 516.2.1 through Section 516.2.9. [NFPA 96:13.2]
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 not less than 18 inches (457 mm) of clearance from the flue outlet to the filter inlet in accordance with Section 509.2.2 through Section 509.2.2.3 and shall be in accordance with the installation requirements of NFPA 54 or NFPA 58. [NFPA 96:13.2.1 - 13.2.3]
Recirculating systems shall be listed with a testing laboratory in accordance with UL 710B or equivalent. [NFPA 96:13.2.4]
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 Section 513.0. [NFPA 96:13.2.4.2]
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 96:13.2.6]
The listing label shall show the type(s) of cooking equipment tested and the maximum limits specified in Section 516.2.4. [NFPA 96:13.2.7]
A fire-actuated damper shall be installed at the exhaust outlet of the system. [NFPA 96:13.2.8] The actuation device for the fire damper shall have a maximum temperature rating of 375°F (191°C). [NFPA 96:13.2.10]
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.
The power supply of an 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 96:13.2.11]
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/in3) (5.0 E-06 kg/m3) of exhausted air sampled from that equipment at maximum amount of product that is capable of 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 the sides, top, and bottom.
  4. Electrical connection in the field in accordance with the California Electrical Code.
  5. Interlocks on 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 96:13.2.12]
The recirculating system shall be provided with interlocks of critical components and operations as indicated in Section 516.3.1 through Section 516.3.3.1 such that, where an interlock is interrupted, the cooking appliance shall not be able to operate. [NFPA 96:13.3.1]
Closure panels encompassing airflow sections shall have interlocks to ensure the panels are in place and fully sealed. [NFPA 96:13.3.2]
Each filter component (grease and odor) shall have an interlock to prove the component is in place. [NFPA 96:13.3.3]
Each ESP shall have a sensor to prove its performance is as designed, with no interruption of the power to exceed 2 minutes. [NFPA 96:13.3.4.1]
The sensor shall be a manual reset device or circuit. [NFPA 96:13.3.4.2]
An airflow switch or transducer shall be provided after the last filter component to ensure that a minimum airflow is maintained. The airflow switch or transducer shall open the interlock circuit where the airflow falls 25 percent below the system's normal operating flow or 10 percent below its listed minimum rating, whichever is lower. The airflow switch or transducer shall be a manual reset device or circuit. [NFPA 96:13.3.5.1 - 13.3.5.3]
The location of recirculating systems shall be approved by the Authority Having Jurisdiction. Items to be reviewed in the fire risk assessment shall include, but not be limited to, life safety, combustibility of surroundings, proximity to air vents, and total fuel load. [NFPA 96:13.4]
In addition to the appliance nozzle(s), a recirculating system shall be listed with the fire protection for grease filters, grease filtration, odor filtration units, and ductwork, where applicable. [NFPA 96:13.5.1]
In addition to other fire-extinguishing system activation device, there shall be a fire-extinguishing system activation device installed downstream of an ESP. [NFPA 96:13.5.2]
The requirements of Section 513.6 shall also apply to recirculating system locations. [NFPA 96:13.5.3]
Automatic or manual covers on cooking appliances, especially fryers, shall not interfere with the application of the fire suppression system. [NFPA 96:13.6.1]
Filters shall be cleaned or replaced in accordance with the manufacturer's instructions. [NFPA 96:13.6.2]
ESPs shall be cleaned a minimum of once per week and in accordance with the manufacturer's instructions. [NFPA 96:13.6.3]
The entire hood plenum and the blower section shall be cleaned not less than once every 3 months. [NFPA 96:13.6.4]
Inspection and testing of the total operation and safety interlocks in accordance with the manufacturer's instructions shall be performed by qualified service personnel not less than once every 6 months, or more frequently where required. [NFPA 96:13.6.5]
Fire-extinguishing equipment shall be inspected in accordance with Section 514.2. [NFPA 96:13.6.6]
A signed and dated log of maintenance as performed in accordance with Section 516.6.3 and Section 516.6.4 shall be available on the premises for use by the Authority Having Jurisdiction. [NFPA 96:13.6.7]
Venting requirements of solid-fuel cooking operations shall be determined in accordance with Section 517.1.1 through Section 517.1.6. [NFPA 96:14.1]
Where solid-fuel cooking equipment is required by the manufacturer to have a natural draft, the vent shall be in accordance with Section 517.4. [NFPA 96:14.1.1]
Where the solid-fuel cooking equipment has a self-contained top, is the appliance to be vented in an isolated space (except for a single water heater with its own separate vent), has a separate makeup air system, and is provided with supply and return air (not supplied or returned from other spaces), the system shall be in accordance with Section 517.4 and Section 517.6. [NFPA 96:14.1.2]
Where the solid-fuel cooking equipment is located in a space with other vented equipment, the vented equipment shall have an exhaust system interlocked with a makeup air system for the space in accordance with Section 517.6. [NFPA 96:14.1.3]
Natural draft ventilation systems and power-exhausted ventilation systems shall comply with Section 517.3, Section 517.4, and Section 517.6. [NFPA 96:14.1.4]
Where a solid-fuel cooking appliance allows effluent to escape from the appliance opening, this opening shall be covered by a hood and an exhaust system that meets the requirements of Section 517.3, Section 517.4, and Section 517.6. [NFPA 96:14.1.5]
Solid-fuel cooking operations shall have spark arresters to minimize the passage of airborne sparks and embers into plenums and ducts. Where the solid-fuel cooking operation is not located under a hood, a spark arrester shall be provided to minimize the passage of sparks and embers into flues and chimneys. [NFPA 96:14.1.6, 14.1.7]
Appliances shall be located with respect to building construction and other equipment so as to permit access to the appliance. [NFPA 96:14.2.1]
Solid-fuel cooking appliances shall not be installed in confined spaces. [NFPA 96:14.2.2]

Exception: Solid-fuel cooking appliances listed for installation in confined spaces such as alcoves shall be installed in accordance with the terms of the listing and the manufacturer's installation instructions. [NFPA 96:14.2.3]
Solid-fuel cooking appliances shall not be installed in a location where gasoline or other flammable vapors or gases are present. [NFPA 96:14.2.4]
Hoods shall be sized and located in a manner capable of capturing and containing the effluent discharging from the appliances. The hood and its exhaust system shall be in accordance with the provisions of Section 508.0 through Section 513.0. [NFPA 96:14.3.1, 14.3.2]
Except as permitted in Section 517.3.1.1, exhaust systems serving solid-fuel cooking equipment, including gas or electrically operated equipment, shall be separate from other exhaust systems. [NFPA 96:14.3.3]

Exception: Cooking equipment not requiring automatic fire-extinguishing equipment (in accordance with Section 513.0) shall be permitted to be installed under a common hood with solid-fuel cooking equipment that is served by a duct system separate from other exhaust systems. [NFPA 96:14.3.5]
Gas-operated equipment utilizing solid fuel for flavoring that is in accordance with the following conditions shall not be required to have a separate exhaust system:
  1. The solid fuel holder (smoker box) shall be listed with the gas-operated equipment.
  2. The solid fuel holder shall be located underneath the gas burner.
  3. Spark arresters that are in accordance with Section 517.1.6 shall be provided.
  4. The maximum quantity of solid fuel consumed shall not exceed 4.5 pounds (2.04 kg) per hour per 100000 Btu/hr (29 k W) of gas burner capacity.
  5. The gas-operated equipment shall be protected by a fire suppression system listed for the equipment, including the solid fuel holder.
  6. Gas-operated equipment with integral solid fuel holder(s) intended for flavoring, such as a radiant charbroiler(s), shall comply with the requirements of UL 300 that address the gas radiant charbroiler(s) and mesquite wood charbroiler(s).
  7. A fire suppression system nozzle(s) shall be installed to protect the solid fuel holder.
  8. The fire suppression system shall be designed and installed to protect the entire cooking operation.
  9. The solid fuel holder shall be limited to a size of 2000 cubic inches (0.0328 m3), with no dimension to exceed 20 inches (508 mm).
  10. A maximum of one solid fuel holder for each 100000 Btu/hr (29 kW), or portion thereof, of burner capacity shall be permitted.
  11. The inspection frequency shall be the same as for solid fuel cooking operations in Table 514.3. [NFPA 96:14.3.4]
Where a hood is not required, in buildings where the duct system does not exceed three stories in height, a duct complying with Section 510.0 shall be provided. [NFPA 96:14.4]
Where a hood is used in buildings where the duct system does not exceed three stories in height, the duct system shall be in accordance with Section 510.0. [NFPA 96:14.4.1]
A listed or approved grease duct system that is four stories in height or more shall be provided for solid-fuel cooking exhaust systems. [NFPA 96: 14.4.2]
Wall terminations of solid-fuel exhaust systems shall be prohibited. [NFPA 96:14.4.4]
Grease removal devices shall be constructed of steel or stainless steel or be approved for solid-fuel cooking. [NFPA 96:14.5.1]
Where airborne sparks and embers can be generated by the solid-fuel cooking operation, spark arrester devices shall be used prior to using the grease removal device, to minimize the entrance of these sparks and embers into the grease removal device and into the hood and duct system. [NFPA 96:14.5.2]
Filters shall be not less than 4 feet (1219 mm) above the appliance cooking surface. [NFPA 96:14.5.3]
Exhaust system requirements shall comply with Section 511.0 for hooded operation or shall be installed in accordance with the manufacturer's installation instructions for unhooded applications. [NFPA 96:14.6.1]
A replacement or makeup air system shall be provided to ensure a positive supply of replacement air at times during cooking operations. [NFPA 96:14.6.2]
Makeup air systems serving solid fuel cooking operations shall be interlocked with the exhaust air system and powered, where necessary, to prevent the space from attaining a negative pressure while the solid-fuel appliance is in operation. [NFPA 96:14.6.3]
Solid-fuel cooking appliances that produce grease-laden vapors shall be protected by listed fire-extinguishing equipment.

Exception: Where acceptable to the Authority Having Jurisdiction, solid-fuel cooking appliances constructed of solid masonry or reinforced portland or refractory cement concrete and vented in accordance with NFPA 211 shall not require fixed automatic fire-extinguishing equipment. [NFPA 96:14.7.1, 14.7.2]
Listed fire-extinguishing equipment shall be provided for the protection of grease removal devices, hoods, and duct systems. [NFPA 96:14.7.3]

Exception: Where acceptable to the Authority Having Jurisdiction, solid-fuel cooking appliances constructed of solid masonry or reinforced portland or refractory cement concrete and vented in accordance with NFPA 211 shall not require automatic fire-extinguishing equipment for the protection of grease removal devices, hoods, and duct systems. [NFPA 96:14.7.4]
Listed fire-extinguishing equipment for solid-fuel-burning cooking appliances, where required, shall be in accordance with Section 513.0 and shall use water-based agents. [NFPA 96:14.7.5]
Fire-extinguishing equipment shall be rated and designed to extinguish solid-fuel cooking fires. The fire-extinguishing equipment shall be of sufficient size to totally extinguish fire in the entire hazard area and prevent reignition of the fuel. [NFPA 96:14.7.6, 14.7.7]
Solid-fuel appliances (whether or not under a hood) with fireboxes of 5 cubic feet (0.14 m3) volume or less shall have not less than a listed 2-A rated water-spray fire extinguisher or a 1.6 gallon (6.1 L) wet chemical fire extinguisher listed for Class K fires in accordance with NFPA 10 with a travel distance of not more than 20 feet (6096 mm) to the appliance. [NFPA 96:14.7.8]
Solid-fuel appliances with fireboxes exceeding 5 cubic feet (0.14 m3) shall be provided with a fixed-water pipe system with a hose in the kitchen capable of reaching the firebox. The hose shall be equipped with an adjustable nozzle capable of producing a fine to medium spray or mist. The nozzle shall be of the type that cannot produce a straight stream. The system shall have an operating pressure of not less than 40 psi (276 kPa) and shall provide not less than 5 gallons per minute (gpm) (0.3 L/s). [NFPA 96:14.7.9]
Fuel storage areas shall be provided with a sprinkler system in accordance with NFPA 13 except where permitted in accordance with the following:
  1. Where approved by the Authority Having Jurisdiction, fuel storage areas shall be permitted to be protected with a fixed water pipe system with a hose capable of reaching all parts of the area.
  2. In lieu of the sprinkler system outlined in Section 517.7.6, a listed 2-A rated water spray fire extinguisher or a 1.6 gallon (6.1 L) wet chemical fire extinguisher listed for Class K fires with a travel distance of not more than 20 feet (6096 mm) to the solid fuel piles shall be permitted to be used for a solid fuel pile, provided that the fuel pile does not exceed 5 cubic feet (0.14 m3). [NFPA 96:14.9.2.8 - 9.2.8.2]
In addition to the requirements of Section 517.7.4, Section 517.7.5 and Section 517.8, where a solid-fuel cooking appliance is also provided with auxiliary electric, gas, oil, or other fuel for ignition or supplemental heat and the appliance is also served by a portion of a fire-extinguishing system in accordance with Section 513.0, such auxiliary fuel shall be shut off upon actuation of the fire-extinguishing system. [NFPA 96:14.7.11]
Metal-fabricated solid-fuel cooking appliances shall be listed for the application where produced in practical quantities or shall be approved by the Authority Having Jurisdiction. Where listed, metal-fabricated solid fuel cooking appliances shall be installed in accordance with the terms of their listings and with the applicable requirements of this chapter. [NFPA 96:14.9.4.1, 14.9.4.2]
Site-built solid-fuel cooking appliances shall be submitted for approval to the Authority Having Jurisdiction before being considered for installation. Units submitted to the Authority Having Jurisdiction shall be installed, operated, and maintained in accordance with the approved terms of the manufacturer's instructions and additional requirements in accordance with the Authority Having Jurisdiction. [NFPA 96:14.9.4.3]
Except for the spark arrester required in Section 517.1.6, there shall be no additional devices in a portion of the appliance, flue pipe, and chimney of a natural draft solid-fuel operation. [NFPA 96:14.9.4.4]
No solid-fuel cooking device shall be permitted for deep-fat frying involving more than 1 quart (qt) (1 L) of liquid shortening, and solid-fuel cooking device shall not be permitted within 3 feet (914 mm) of a deep-fat frying unit. [NFPA 96:14.9.4.5]
A downdraft appliance ventilation system containing, or for use with appliances used in processes that produce, smoke or grease-laden vapors shall be equipped with components that are in accordance with the following:
  1. The clearance requirements in accordance with Section 507.3.
  2. The primary collection means designed for collecting cooking vapors and residues in accordance with the requirements of Section 508.0.
  3. Grease removal devices that comply with Section 509.0.
  4. Special-purpose filters as listed in accordance with UL 1046.
  5. Exhaust ducts that comply with Section 510.0.
  6. The air movement requirements in accordance with Section 511.2.1 and Section 511.2.2.
  7. Auxiliary equipment (such as particulate and odor removal devices) are in accordance with Section 512.0.
  8. Fire-extinguishing equipment that is in accordance with the requirements of Section 513.0, and as specified in Section 518.3.
  9. The use and maintenance requirements in accordance with Section 514.0.
  10. The minimum safety requirements in accordance with Section 515.0. [NFPA 96:15.1.1]
The downdraft appliance ventilation system shall be capable of capturing and containing the effluent discharge from the appliance(s) it is serving. [NFPA 96:15.1.2]
Fire-extinguishing equipment on a downdraft appliance ventilation system shall comply with the following:
  1. Cooking surface, duct, and plenum protection shall be provided.
  2. Not less than one fusible link or heat detector shall be installed within an exhaust duct opening in accordance with the manufacturer's listing.
  3. A fusible link or heat detector shall be provided above the protected cooking appliance and in accordance with the extinguishing system manufacturer's listing.
  4. A manual activation device shall be provided as part of the appliance at a height approved by the Authority Having Jurisdiction.
  5. Portable fire extinguishers shall be installed in accordance with Section 513.11. [NFPA 96:15.2]
A listed downdraft appliance ventilation system employing an integral fire-extinguishing system including detection systems that has been evaluated for grease and smoke capture, fire extinguishing, and detection shall be considered to be in accordance with Section 518.3. [NFPA 96:15.2.1]
The downdraft appliance ventilation system shall be provided with interlocks such that the cooking fuel supply will not be activated unless the exhaust and supply air system have been activated. [NFPA 96:15.2.2]
An airflow switch or transducer shall be provided after the last filter component to ensure that a minimum airflow is maintained. [NFPA 96:15.3.1]
The airflow switch or transducer shall open the interlock circuit where the airflow is less than 25 percent the system's normal operating flow or less than 10 percent its listed minimum rating, whichever is less. [NFPA 96:15.3.2]
The airflow switch or transducer shall be a manual reset device or circuit. [NFPA 96:15.3.3]
Surfaces located directly above the cooking appliance shall be of noncombustible or limited-combustible materials. [NFPA 96:15.4]
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