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71

CALIFORNIA MECHANICAL CODE – MATRIX ADOPTION TABLE

CHAPTER 5 – EXHAUST SYSTEMS

Adopting Agency BSC SFMHCD DSA OSHPD

CA DPH1 2 1/AC AC SS SS/CC 1 2 3 4

Adopt Entire Chapter

Adopt Entire Chapter as amended

(amended sections listed below)X X X X X X X X X X X

Adopt only those sections that are

listed below X

Article/Section

504.1 X X X

505.5 X

505.5.1 X

506.2 X X X X X X X X X X

508.1.1 X X X

509.2.4 X

509.2.4.4 X

513.2.2 X

513.3.2 X

513.11.1 X

513.11.2 X

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501.0 Scope.

This Chapter includes requirements for environmental airducts, product-conveying systems, and commercial hoods andkitchen ventilation.

Part I – Environmental Air Ducts and Product-Conveying Systems.

502.0 Definitions.

For the purposes of this Chapter, the following definitionsapply:

Access Panel. A closure device used to cover an opening intoa duct, an enclosure, equipment, or an appurtenance. [NFPA96:3.3.1]

Air Intakes. An opening in a building's envelope whosepurpose is to allow outside air to be drawn into the structureto replace inside air that is removed by exhaust systems or toimprove the quality of the inside air by providing a source ofair having a lower concentration of odors, suspended parti-cles, or heating content. [NFPA 96:3.3.2]

Air Pollution Control Devices. Equipment and devices usedfor the purpose of cleaning air passing through them or bythem in such a manner as to reduce or remove the impuritiescontained therein. [NFPA 96:3.3.3]

Appurtenance. An accessory or a subordinate part thatenables the primary device to perform or improve its intendedfunction. [NFPA 96:3.3.5]

Baffle Plate. An object placed in or near an appliance tochange the direction or retard the flow of air, air-fuelmixtures, or flue gases. [NFPA 96:3.3.7]

Certified Person. A person trained and certified by the equip-ment manufacturer, or by a recognized organization througha formal certification program for the system to be servicedor cleaned, that is acceptable to the Authority Having Juris-diction.

Classified. See Listed.

Clean(ing). For kitchen exhaust systems and cooking equip-ment, the act of removing grease, oil deposits, and otherresidue. [NFPA 96:3.3.11]

Clearly Identified. Capable of being recognized by a personof normal vision without causing uncertainty and indecisive-ness about the location or operating process of the identifieditem. [NFPA 96:3.3.12]

Closed Combustible Construction. Combustible buildingconstruction, including walls, structural framing, roofs, roofceilings, floors, and floor-ceiling assemblies continuouslyenclosing a grease duct on four sides where one or more sidesrequire protection per Section 507.2. [NFPA 96:3.3.13.1]

Combustible Material. Material subject to an increase incombustibility or flame-spread rating beyond the limits estab-lished in the definition of Limited-Combustible Material.

Commercial Food Heat-Processing Equipment. Equip-ment used in a food establishment for heat-processing food orutensils and that produces grease vapors, steam, fumes,smoke, or odors that are required to be removed through alocal exhaust ventilation system.

Compensating Hood. A hood that has an outside-air supplywith air delivered below or within the hood. When makeup airis diffused directly into the exhaust within the hood cavity, itbecomes a short-circuit hood.

Concealed Spaces. That portion(s) of a building behindwalls, over suspended ceilings, in pipe chases, attics, and else-where whose size might normally range from 13⁄4 inch (44.45mm) stud spaces to eight (8) foot (2.44 m) interstitial trussspaces and that might contain combustible materials such asbuilding structural members, thermal and/or electrical insu-lation, and ducting. Such spaces have sometimes been used asHVAC plenum chambers. [NFPA 96:3.3.45.1]

Continuous Enclosure. A recognized architectural ormechanical component of a building having a fire resistancerating as required for the structure and whose purpose is toenclose the vapor removal duct for its full length to its termi-nation point outside the structure without any portion of theenclosure having a fire resistance rating less than the requiredvalue. [NFPA 96:3.3.22.1]

Continuous Weld. A metal-joining method that produces aproduct without visible interruption or variation in quality.For the purpose of the definition, it specifically includes theexhaust compartment of hoods and welded joints of exhaustducts, yet specifically does not include filter support framesor appendages inside hoods. [NFPA 96:3.3.14]

Cooking Appliance Flue Outlet. The opening or openings ina cooking device where vapors, combustion gases, or bothleave the cooking device. There might or might not be duct-work attached to this opening.

Damper. A valve or plate within a duct or its terminal compo-nents for controlling draft or the flow of gases, including air.[NFPA 96:3.3.15]

Detection Devices. Electrical, pneumatic, thermal, mechan-ical, or optical sensing instruments, or subcomponents of suchinstruments, whose purpose is to cause an automatic actionupon the occurrence of some preselected event. In the contextof this document, the event in question could be excessivetemperature or flame, and the action could be the operation ofa fire-extinguishing system.

Dips. Depression or cup like places in horizontal duct runs inwhich liquids could accumulate. [NFPA 96:3.3.17]

Discharge. The final portion of a duct or pipe where theproduct being conveyed is emptied or released from confine-ment; the termination point of the pipe or duct. [NFPA96:3.3.18]

Easily Accessible. See Accessible, Readily in Section 203.0,Chapter 2.

CHAPTER 5EXHAUST SYSTEMS

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EXHAUST SYSTEMS

Environmental Air Duct. Ducting used for conveying air attemperatures not exceeding 250˚F (121˚C) to or from occu-pied areas of any occupancy through other than heating orair-conditioning systems, such as ventilation for humanusage, domestic kitchen range exhaust, bathroom exhaustducts, and domestic-type clothes dryer exhaust ducts.

Factory-Built Grease Enclosures. A listed factory-builtgrease duct enclosure system evaluated for reduced clear-ances to combustibles, and as an alternative to a duct with itsfire-rated enclosure. [NFPA 96:3.3.22.2.1]

Field-Applied Grease Duct Enclosures. A listed systemevaluated for reduced clearances to combustibles, and as analternative to a duct with its fire-rated enclosure. [NFPA96:3.3.22.2.2]

Fire Barrier Wall. A wall assembly complying with therequirements of NFPA 221, Standard for Fire Walls and FireBarrier Walls, having a fire resistance rating of four (4) hours.

Fire Partition. An interior wall or partition of a building thatseparates two areas and serves to restrict the spread of firebut does not qualify as a fire wall.

Fire Resistance Rating. A relative value in minutes or hoursassigned to materials or assemblies that have withstood a fireexposure as established in accordance with NFPA 251, Stan-dard Methods of Tests of Fire Endurance of BuildingConstruction and Materials.

Flammable Vapor or Fumes. The concentration of flam-mable constituents in air that exceeds twenty-five percent(25%) of its Lower Flammability Limit (LFL).

Fume Incinerators. Devices utilizing intense heat or fire tobreak down and/or oxidize vapors and odors contained in gasesor air being exhausted into the atmosphere. [NFPA 96:3.3.27]

Fusible Link. A form of fixed-temperature heat-detecting devicesometimes employed to restrain the operation of an electrical ormechanical control until its designed temperature is reached.Such devices are to be replaced following each operation.

Grease. Rendered animal fat, vegetable shortening, and othersuch oily matter used for the purposes of and resulting fromcooking and/or preparing foods. Grease might be liberated andentrained with exhaust air or might be visible as a liquid or solid.

Grease Ducts. A containment system for the transportation ofair and grease vapors that is designed and installed to reducethe possibility of the accumulation of combustible condensa-tion and the occurrence of damage if a fire occurs within thesystem. [NFPA 96:3.3.20.2]

Grease Filter. A removable component of the grease removalsystem designed to capture grease and direct it to a safecollection point before it enters a duct system. Filters areexpected to minimize the projection of flames downstreamwhen attacked by flame on the upstream side and areexpected to maintain their strength, shape, and integrity whenexposed to the anticipated rough handling, cleaning, andservice found in the field.

Grease Filter, Mesh-Type. A general-purpose air filterdesigned to collect and retain lint and grease from the airpassing through it. This type of filter is not tested, listed, oracceptable for commercial cooking operations due to theincreased fire hazard.

Grease Removal Devices. A system of components designedfor and intended to process vapors, gases, and/or air as it isdrawn through such devices by collecting the airborne greaseparticles and concentrating them for further action at somefuture time, leaving the exiting air with a lower amount ofcombustible matter. [NFPA 96:3.3.30]

Grease-Tight. Constructed and performing in such a manneras not to permit the passage of any grease under normalcooking conditions. [NFPA 96:3.3.31]

High Broiler. See Upright Broiler.[NFPA 96:3.3.8.1]

High Limit Control. An operating device installed in andserving as an integral component of a deep-fat fryer. Itspurpose is the secondary limitation of temperature allowedby the cooking operation and, if that temperature is exceeded,the automatic interruption of the thermal energy input. [NFPA96:3.3.32]

Hood. An air-intake device connected to a mechanicalexhaust system for collecting and removing grease, vapors,fumes, smoke, steam, heat, or odors from commercial foodheat-processing equipment.

Fixed Baffle. A listed unitary exhaust hood design wherethe grease removal device is a nonremovable assemblythat contains an integral fire-activated water-wash fire-extinguishing system listed for this purpose. [NFPA96:3.3.33.1]

Type I. is a kitchen hood for collecting and removinggrease and smoke.

Type II. is a general kitchen hood for collecting andremoving steam, vapor, heat, or odors.

Interconnected. Mutually assembled to another componentin such a manner that the operation of one directly affects theother or that the contents of one specific duct system areallowed to encounter or contact the products being moved byanother duct system. [NFPA 96:3.3.34]

Limited-Combustible Material. A building constructionmaterial that does not comply with the definition of noncom-bustible material, that, in the form in which it is used, has apotential heat value not exceeding 3,500 Btu/lb. (8141 kJ/kg)(See NFPA 259, Standard Test Method for Potential Heat ofBuilding Materials), and that complies with either of thefollowing (A) or (B). Materials subject to an increase incombustibility or flame-spread rating beyond the limits hereinestablished through the effects of age, moisture, or otheratmospheric conditions shall be considered combustible.

(A) Materials having a structural base of noncombustiblematerial, with a surfacing not exceeding a thickness of1⁄8 inch (3.2 mm), and with a flame-spread rating notgreater than fifty (50).

(B) Materials in the form and thickness used, other than asdescribed in (A), having neither a flame-spread ratinggreater than twenty-five (25) nor evidence of continuedprogressive combustion and of such composition thatsurfaces that would be exposed by cutting through thematerial on any plane would have neither a flame-spreadrating greater than twenty-five (25) nor evidence ofcontinued progressive combustion.

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EXHAUST SYSTEMS

Liquid-Tight. Constructed and performing in such a manneras not to permit the passage of any liquid at any temperature.[NFPA 96:3.3.35]

Noncombustible Material. A material that, in the form inwhich it is used and under the conditions anticipated, will notignite, burn, support combustion, or release flammable vaporswhen subjected to fire or heat. Materials that are reported aspassing ASTM E 136, Standard Test Method for Behavior ofMaterials in a Vertical Tube Furnace at 750°C, shall beconsidered noncombustible materials. [NFPA 220:3.3.4]

Open Combustible Construction. Combustible buildingconstructions including wall, structural framing, roof, roofceiling, floor, and floor ceiling assemblies adjacent to a greaseduct on three or fewer sides where one or more sides requireprotection per Section 507.2. [NFPA 96:3.3.13.2]

Pitched. To be fixed or set at a desired angle or inclination.[NFPA 96:3.3.37]

Product-Conveying Duct. Ducting used for conveying solidparticulates, such as refuse, dust, fumes, and smoke; liquidparticulate matter, such as spray residue, mists, and fogs;vapors, such as vapors from flammable or corrosive liquids;noxious and toxic gases; and air at temperatures exceeding250°F (121°C).

Recirculating Systems. Systems for control of smoke orgrease-laden vapors from commercial cooking equipment thatdo not exhaust to the outside. [NFPA 96:3.3.39]

Removable. Capable of being transferred to another locationwith a limited application of effort and tools. [NFPA 96:3.3.40]

Replacement Air. See Air, Makeup in Section 203.0,Chapter 2.

Salamander Broiler. See Upright Broiler. [NFPA 96:3.3.8.2]

Secondary Filtration. Fume incinerators, thermal recoveryunits, air pollution control devices or other filtration mediainstalled in ducts or hoods located in the path of travel ofexhaust products after the initial filtration.

Shall. Indicates a mandatory requirement.

Single Hazard Area. As considered in the applicable extin-guishing system standard (See Section 513.2) or as deter-mined by the Authority Having Jurisdiction.

Solid Cooking Fuel. Any solid, organic, consumable fuelsuch as briquette, mesquite, hardwood, or charcoal. [NFPA96:3.3.43]

Solid-Fuel Cooking Equipment. Cooking equipment that isfired with solid cooking fuel. This equipment includes ovens,tandoori charcoal pots, grills, broilers, rotisseries, barbecuepits, or any other type of cooking equipment that derives allor part of its heat source from the burning of solid cookingfuel.

Solvent. A substance (usually liquid) capable of dissolvingor dispersing another substance; a chemical compounddesigned and used to convert solidified grease into a liquidor semi-liquid state in order to facilitate a cleaning operation.[NFPA 96:3.3.44]

Spark Arrester. A device or method that minimizes thepassage of airborne sparks and embers into a plenum, duct,and flue. [NFPA 96:3.3.46]

Termination. The final or intended end portion of a ductsystem that is designed and functions to fulfill the obligationsof the system in a satisfactory manner.

Thermal Recovery Unit. A device or series of devices whosepurpose is to reclaim only the heat content of air, vapors, gases,or fluids that are being expelled through the exhaust systemand to transfer the thermal energy so reclaimed to a locationwhereby a useful purpose can be served. [NFPA 96:3.3.47]

Trap. A cup like or U-shaped configuration located on theinside of a duct system component where liquids can accu-mulate. [NFPA 96:3.3.49]

Upright Broiler. An appliance used in the preparation of foodwhereby foods are exposed to intense radiant heat, andperhaps to convective heat, with the food and the radiantsource not limited to a horizontal mode. [NFPA 96:3.3.8.3]

502.1 Product-Conveying Ducts – Classification.

Product-conveying ducts shall be classified according to theiruse, as follows:

Class 1. Ducts conveying nonabrasives, such as smoke,spray, mists, fogs, noncorrosive fumes and gases,light fine dusts, or powders.

Class 2. Ducts conveying moderately abrasive particulate inlight concentrations, such as sawdust and grain dust,and buffing and polishing dust.

Class 3. Ducts conveying Class 2 materials in high concen-trations and highly abrasive materials in low concen-trations, such as manganese, steel chips, and coke.

Class 4. Ducts conveying highly abrasive material in highconcentrations.

Class 5. Ducts conveying corrosives, such as acid vapors.

503.0 Motors, Fans, and Filters.

503.1 General. Motors and fans shall be sized to provide therequired air movement. Motors in areas that contain flammablevapors or dusts shall be of a type approved for such environ-ments. A manually operated remote control installed at anapproved location shall be provided to shut off fans or blowersin flammable vapor or dust systems. Electrical equipment usedin operations that generate explosive or flammable vapors,fumes, or dusts shall be interlocked with the ventilation systemso that the equipment cannot be operated unless the ventilationfans are in operation. Motors for fans used to convey flam-mable vapors or dusts shall be located outside the duct or shallbe protected with approved shields and dustproofing. Motorsand fans shall be accessible for servicing and maintenance.

503.2 Fans. Parts of fans in contact with explosive or flam-mable vapors, fumes, or dusts shall be of nonferrous ornonsparking materials or their casing shall be lined orconstructed of such material. When the size and hardness ofmaterials passing through a fan could produce a spark, boththe fan and the casing shall be of nonsparking materials. Whenfans are required to be spark-resistant, their bearings shall notbe within the airstream, and all parts of the fan shall begrounded. Fans in systems handling materials that are likely toclog the blades, and fans in buffing or woodworking exhaustsystems, shall be of the radial-blade or tube-axial type.

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Equipment used to exhaust explosive or flammablevapors, fumes, or dusts shall bear an identification platestating the ventilation rate for which the system was designed.

Fans located in systems conveying corrosives shall be ofmaterials that are resistant to the corrosive or shall be coatedwith corrosion-resistant materials.

503.3 Air filters shall be listed units. Liquid adhesive coat-ings used on filters shall have a flash point of 350˚F (177˚C)or higher, as determined by the Fire Code standards.

504.0 Environmental Air Ducts.

504.1 Makeup and Exhaust-Air Ducts. Environmental airducts not regulated by other provisions of this Code shallcomply with this Section. Ducts shall be substantially airtightand shall comply with the provisions of Chapter 6. Exhaustducts under positive pressure shall not extend into or throughducts or plenums. Exhaust ducts shall terminate outside thebuilding and shall be equipped with back-draft dampers.[OSHPD 1, 2 & 4] Exception: Back-draft dampers are notrequired when the exhaust fan must operate continuously.Environmental air ducts that have an alternate function as apart of an approved smoke-control system do not requiredesign as Class 1 product-conveying ducts.

504.2 Domestic Range Vents. Ducts used for domestickitchen range ventilation shall be of metal and shall havesmooth interior surfaces. Ducts for domestic range hoodsshall only serve cooking appliances.

Exception: Ducts for domestic kitchen downdraft grill-rangeventilation installed under a concrete slab floor may be ofapproved Schedule 40 PVC provided:

(1) The under-floor trench in which the duct is installed shallbe completely backfilled with sand or gravel.

(2) Not more than one (1) inch (25 mm) of six (6) inch diam-eter (152 mm) PVC coupling may protrude above theconcrete floor surface.

(3) PVC pipe joints shall be solvent cemented to providedan air and grease-tight duct.

(4) The duct shall terminate above grade outside the buildingand shall be equipped with a back-draft damper.

504.3 Clothes Dryers.

504.3.1 Moisture Exhaust Ducts. Moisture exhaustducts shall terminate on the outside of the building andshall be equipped with a back-draft damper. Screens shallnot be installed at the duct termination. Ducts forexhausting clothes dryers shall not be connected orinstalled with sheet metal screws or other fasteners thatwill obstruct the flow. Clothes dryer moisture exhaustducts shall not be connected to a gas vent connector, gasvent, or chimney, and shall only serve clothes dryers.Clothes dryer moisture exhaust ducts under positive pres-sure shall not extend into or through ducts or plenums.

504.3.2 Domestic Clothes Dryers. When a compartmentor space for a domestic clothes dryer is provided, aminimum four (4) inch diameter (102 mm) moistureexhaust duct of approved material shall be installed inaccordance with this Section and Section 504.0.

When a closet is designed for the installation of aclothes dryer, a minimum opening of 100 square inches(64,516 mm2) for makeup air shall be provided in thedoor or by other approved means.

504.3.2.1 Domestic Dryer Vents. Domestic clothesdryer moisture exhaust ducts shall be of metal andshall have smooth interior surfaces.

Exception: Listed clothes dryer transition ducts notmore than six (6) feet (1,829 mm) in length may beused in connection with domestic dryer exhausts.

Flexible clothes dryer transition ducts shall notbe concealed within construction.

504.3.2.2 Length Limitation. Unless otherwisepermitted or required by the dryer manufacturer’sinstallation instructions and approved by theAuthority Having Jurisdiction, domestic dryer mois-ture exhaust ducts shall not exceed a total combinedhorizontal and vertical length of fourteen (14) feet(4,263 mm), including two (2) 90 degree (1.57 rad)elbows. Two (2) feet (610 mm) shall be deducted foreach 90 degree (1.57 rad) elbow in excess of two.

504.3.3 Commercial Clothes Dryers. Commercialdryer exhaust ducts shall be installed in accordance withtheir listings. The installation of commercial clothesdryer exhaust ducts shall comply with the appliancemanufacturer’s installation instructions.

504.4 Heat (Energy) Recovery Ventilators.

504.4.1 Heat (energy) recovery ventilators shall beinstalled in accordance with their listings and complywith the appliance manufacturer’s installation instruc-tions. Heat (energy) recovery ventilator ducts shallcomply with the provisions of Chapter 6.

504.5 Termination of Environmental Air Ducts. Environ-mental air duct exhaust shall terminate a minimum of three(3) feet (914 mm) from property line and three (3) feet (914mm) from openings into the building.

504.6 Gypsum Wallboard Ducts. Bathroom and laundryroom exhaust ducts may be of gypsum wallboard subject tothe limitations of Section 602.1.

505.0 Design of Product-Conveying Ventilation Systems.

505.1 General. A mechanical ventilation or exhaust systemshall be installed to control, capture, and remove emissionsgenerated from product use or handling when required by theBuilding Code or Fire Code and when such emissions result ina hazard to life or property. The design of the system shall besuch that the emissions are confined to the area in which theyare generated by air currents, hoods, or enclosures and shall beexhausted by a duct system to a safe location or treated byremoving contaminants. Ducts conveying explosives or flam-mable vapors, fumes, or dusts shall extend directly to the exte-rior of the building without entering other spaces and shall notextend into or through ducts and plenums.

Exception: Ducts conveying vapor or fumes having flam-mable constituents less than 25 percent of their Lower Flam-mability Limit (LFL) may pass through other spaces.

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505.1.1 Incompatible materials shall not be conveyed inthe same system.

505.1.2 In systems conveying flammable vapors, gases,or mists, the concentration shall not exceed 25 percentof the lower flammability limit (LFL).

Exception: Higher concentrations shall be permitted ifthe exhaust system is designed and protected in accor-dance with the Standard on Explosion PreventionSystems in Chapter 17, using one or more of thefollowing techniques:

(1) Combustible concentration reduction

(2) Oxidant concentration reduction

(3) Deflagration suppression

(4) Deflagration pressure containment

Separate and distinct systems shall be provided forincompatible materials.

Contaminated air shall not be recirculated to occu-pied areas unless contaminants have been removed. Aircontaminated with explosive or flammable vapors,fumes, or dusts; flammable or toxic gases; or radioactivematerial shall not be recirculated.

505.2 Minimum Velocities and Circulation. The velocityand circulation of air in work areas shall be such that contam-inants are captured by an airstream at the area where the emis-sions are generated and conveyed into a product-conveyingduct system. Mixtures within work areas where contaminantsare generated shall be diluted below twenty-five (25) percentof their lower explosive limit or lower flammability limit withair that does not contain other contaminants. The velocity ofair within the duct shall be not less than set forth in Table 5-1.

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

employing the constant velocity method. Systems conveying

explosive or radioactive materials shall be prebalanced

through duct sizing. Other systems may 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.

505.3 Makeup Air. 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.

505.4 Hoods and Enclosures. Hoods and enclosures shall be

used when 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 as set forth in Section 505.2. Hoods of steel shall

have a base metal thickness not less than 0.027 inch (0.69 mm)

(No. 22 gauge) for Class 1 and Class 5 metal duct systems;

0.033 inch (0.84 mm) (No. 20 gauge) for hoods serving a Class

2 duct system; 0.044 inch (1.12 mm) (No. 18 gauge) for hoods

serving a Class 3 duct system; and 0.068 inch (1.73 mm) (No.

14 gauge) for hoods serving a Class 4 duct system.

Approved nonmetallic hoods and duct systems may be

used for Class 5 corrosive systems when the corrosive

mixture is nonflammable. Metal hoods used with Class 5 duct

systems shall be protected with suitable 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.

505.5 Pharmacies – Compounding Area of Parenteral Solu-

tions. [CA – Board of Pharmacy] The pharmacy shall have

a designated area for the preparation of sterile products for

dispensing which shall be ventilated in a manner not inter-

fering with laminar air flow.

Note: For additional pharmacy building standard require-

ments, see Chapter 12, California Building Code.

505.5.1 Pharmacies – laminar flow biological safety

cabinet. [CA – Board of Pharmacy] In all pharmaciespreparing parenteral cytotoxic agents, all compoundingshall be conducted within a certified Class II Type A or ClassII Type B vertical laminar airflow hood with bag in – bag outdesign. The pharmacy must ensure that contaminated airplenums that are under positive air pressure are leak tight.

Note: For additional pharmacy building standardrequirements, see Chapter 12, California Building Code.

506.0 Product-Conveying Ducts.

506.1 Materials. Materials used in product- conveying ductsystems shall be suitable for the intended use and shall be ofmetal.

FEET PERMINUTE

(M/S)

Vapors, gases, smoke, fumes Any Any

Fine light dusts, such as cotton, lint,

and wood flour (100 mesh and under)

2,000 (10.2)

Dry dusts; powders, such as fine rubber

molding power, soap dust2,5001 (12.7)1

Industrial dusts

Average dusts, such as sawdust,

grinding dust, coal dust

Heavy dusts, such as metal turnings,

lead dusts

Moist dusts and chips, such as lead dust

with chips, sticky buffing lint, quick-

lime dust

3,500

4,000

4,500

(17.8)

(20.3)

(22.9)

TABLE 5-1MINIMUM CONvEYINg vELOCITIES

Note:1 The velocity for aluminum and magnesium powder shall be not less

than 4,000 feet per minute (20.3 m/s).

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Exceptions:

(1) Asbestos-cement, concrete, clay, or ceramic materialsmay be used when it is shown that these materials will beequivalent to metal ducts installed in accordance withthis Chapter.

(2) Ducts serving a Class 5 system may be constructed ofapproved nonmetallic material when the corrosive char-acteristics of the material being conveyed make a metalsystem unsuitable and when the mixture being conveyedis nonflammable.

Approved nonmetallic material shall be either alisted product having a flame-spread index of twenty-five(25) or less and a smoke-developed rating of fifty (50)or less on both inside and outside surfaces withoutevidence of continued progressive combustion, or shallhave a flame-spread index of twenty-five (25) or less andshall be installed with an automatic fire-sprinkler protec-tion system inside the duct.

(3) Ducts used in central vacuum cleaning systems within adwelling unit shall be constructed of materials in compli-ance with the applicable standards referenced in Chapter17. Penetrations of fire walls or floor-ceiling orroof-ceiling assemblies shall comply with the BuildingCode.

Copper or ferrous pipes or conduits extending fromwithin the separation between a garage and dwelling unitto the central vacuuming unit may be used.

Aluminum ducts shall not be used in systems conveyingflammable vapors, fumes, or explosive dusts, nor in Class 2,3, or 4 systems. Galvanized steel and aluminum ducts shallnot be used when the temperature of the material beingconveyed exceeds 400˚F (205˚C).

Metal ducts used in Class 5 systems that are not resistantto the corrosiveness of the product shall be protected withappropriate corrosion-resistant material.

506.2 Construction. Ducts used for conveying products shallbe of substantial airtight construction and shall not have open-ings other than those required for operation and maintenanceof the system. Ducts constructed of steel shall comply withTable 5-5 or 5-6.

Exceptions:

(1) Class 1 product-conveying ducts that operate at less thanfour (4) inches (102 mm) water column (995.6 Pa) nega-tive pressure and convey noncorrosive, nonflammable,and nonexplosive materials at temperatures notexceeding 250°F (121°C) may be constructed in accor-dance with ANSI/SMACNA 006-2006 HVAC DuctConstruction Standards - Metal and Flexible or anotherapproved duct construction standard.

(2) Ducts used in central vacuuming systems within adwelling unit shall be constructed of materials in compli-ance with the applicable standards referenced in Chapter17. Penetrations of fire-resistive walls, or floor-ceilingor roof-ceiling assemblies shall comply with the BuildingCode. Copper or ferrous pipes or conduit extending fromwithin the separation between a garage and dwelling unitto the central vacuum unit may be used.

The use of rectangular ducts conveying particulates shallbe subject to approval of the building official. The design ofrectangular ducts shall consider the adhesiveness and buildupof products being conveyed within the duct.

Aluminum construction may be used in Class 1 ductsystems only. The thickness of aluminum ducts shall be atleast two Brown and Sharpe gauges thicker than the gaugesrequired for steel ducts set forth in Tables 5-5 and 5-6.

506.3 Fittings. Fittings in Class 2, 3, and 4 systems shall benot less than two gauges thicker than the thickness requiredfor straight runs. Flexible metallic duct may be used forconnecting ductwork to vibrating equipment. Duct systemssubject to wide temperature fluctuations shall be providedwith expansion joints.

Branches shall connect to main ducts at the large end oftransitions at an angle not exceeding forty-five (45) degrees(0.79 rad).

Except for ducts used to convey noncorrosive vapors withno particulate, accessible cleanouts shall be provided at ten (10)foot (3,048 mm) intervals and at changes in direction. Accessopenings shall also be provided for access to sprinklers andother equipment within the duct that require servicing.

506.4 Explosion Venting. Ducts conveying explosive dustsshall have explosion vents, openings protected by antiflash-back swing valves, or rupture diaphragms. Openings torelieve explosive forces shall be located outside the building.When relief devices cannot provide sufficient pressure relief,ductwork shall be designed to withstand an internal pressureof not less than 100 pounds per square inch (689 kPa).

If a room or building contains a dust explosion hazardthat is external to protected equipment, as defined in 2.2.3.1of NFPA 654, Prevention of Fire and Duct Explosions fromthe Manufacturing, Processing, and Handling of CombustibleParticulate Solids, such areas shall be provided with defla-gration venting to a safe outside location.

506.5 Supports. Spacing of supports for ducts shall notexceed twelve (12) feet (3,658 mm) for eight (8) inch (203mm) ducts nor twenty (20) feet (6,096 mm) for larger ducts,unless justified by the design.

506.5.1 Duct supports shall be designed to carry the weightof the duct half filled with material. Where sprinkler protec-tion is provided in the duct, the hanger’s design shall includethe weight of the duct half filled with water or with thematerial being conveyed, whichever has the higher density.Loads shall not be placed on connecting equipment.

Exception: Where adequate drainage is provided, theweight of the water shall not require consideration.

506.5.2 Hangers and supports exposed to corrosiveatmospheres shall be Type 316 SS or equivalent.

506.5.3 To avoid vibration and stress on the duct, hangersand supports shall be securely fastened to the building orstructure.

506.5.4 Hangers and supports shall be designed to allowfor expansion and contraction. [NFPA 91:4.5.6]

506.6 Fire Protection. Sprinklers or other fire-protectiondevices shall be installed within ducts having a cross-sectionaldimension exceeding ten (10) inches (254 mm) when the duct

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EXHAUST SYSTEMS

conveys flammable vapors or fumes. Sprinklers shall beinstalled at twelve (12) foot (3,658 mm) intervals in horizontalducts and at changes in direction. In vertical runs, sprinklersshall be installed at the top and at alternate floor levels.

506.7 Duct Clearances.

506.7.1 All ductwork and system components handlingcombustible material and operating at less than 140°F(60°C) shall have a clearance of not less than eighteen(18) inches (457 mm) from combustible construction orany combustible material.

Exceptions:

(1) When the ductwork system is equipped with anapproved automatic extinguishing system designed

for the specific hazard, the clearance shall bepermitted to be reduced to six (6) inches (152 mm )from combustible materials and 1⁄2 inch (13 mm)from combustible construction.

(2) When the combustible material and construction isprotected by the use of materials or products listed forprotection purposes or in accordance with Table 5-2.

506.7.1.1 Spacers and ties for protection materialsshall be of noncombustible material and shall not beused directly behind the duct.

506.7.1.2 With all clearance reduction systems using

a ventilated airspace, air circulation shall be

provided as described in Table 5-2. There shall be at

Notes:

1. A = required clearance with no protection.

2. B = reduced clearance permitted.

3. The protection applied to the construction using combustible material shall extend far enough in each direction make C = A

TABLE 5-2REDUCTION OF DUCT CLEARANCE WITH SPECIFIED FORMS OF PROTECTION

CLEARANCE REDUCTION APPLIED TO AND COvERINg ALL COMBUSTIBLE SURFACES WITH THE DISTANCE SPECIFIED AS REqUIRED CLEARANCE WITH NO PROTECTION IN 506.7.2

MINIMUM ALLOWABLEREDUCTION IN CLEARANCE (%)

FORM OF PROTECTIONAS WALL

PROTECTORAS CEILINgPROTECTOR

(a) 31⁄2 in. (90 mm) thick masonry wall without ventilated airspace 33 ––

(b) 1⁄2 in. (13 mm) thick noncombustible insulation board over 1 in. (25.4 mm) glass fiber or mineral wool

batts without ventilated airspace

50 33

(c) 0.024 in. (0.61 mm) (No. 24 gauge) sheet metal over 1 in. (25.4 mm) glass fiber or mineral wool batts

reinforced with wire, or equivalent, on rear face with at least a 1 in. (25.4 mm) air gap

66 66

(d) 31⁄2 in (90 mm) thick masonry wall with at least a 1 in (25.4 mm) air gap 66 ––

(e) 0.024 in. (0.61 mm) (No. 24 gauge) sheet metal with at least a 1 in. (25.4 mm) air gap 66 50

(f) 1⁄2 in. (13 mm) thick noncombustible insulation board with at least a 1 in. (25.4 mm) air gap 66 50

(g) 0.024 in. (0.61mm) (No. 24 gauge) sheet metal with ventilated airspace over 0.024 in. (0.61 mm) (No.

24 gauge) sheet metal with at least a 1 in. (25.4 mm) air gap

66 50

(h) 1 in. (25.4 mm) glass fiber or mineral wool batts sandwiched between two sheets 0.024 in. (0.61 mm)

(No. 24 gauge) sheet metal with at least a 1 in. (25.4 mm) air gap

66 50

EXTENT OF PROTECTION REqUIRED TO REDUCE CLEARANCES FROM DUCTS.

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EXHAUST SYSTEMS

WHERE THE REqUIRED CLEARANCE WITH NO PROTECTION FROM APPLIANCE, vENT CONNECTOR, OR SINgLE-WALL METAL PIPE IS:

36 in. 18 in. 12 in. 9 in. 6 in.

ALLOWABLE CLEARANCES WITH SPECIFIED PROTECTION (in.)

TYPE OF PROTECTION APPLIEDTO AND COvERINg SURFACES OFCOMBUSTIBLE MATERIAL WITHIN

THE DISTANCE SPECIFIED AS THE REqUIRED CLEARANCE

WITH NO PROTECTION [SEE FIgURES 5-4 THROUgH 5-6.]

USE COL. 1 FOR CLEARANCES ABOvE APPLIANCE OR HORIzONTAL CONNECTOR. USE COL. 2 FOR

CLEARANCES FROM APPLIANCES, vERTICAL CONNECTOR, AND SINgLE-WALL METAL PIPE.

ABOvE

COL. 1

SIDES

AND

REAR

COL. 2

ABOvE

COL. 1

SIDES

AND

REAR

COL. 2

ABOvE

COL. 1

SIDES

AND

REAR

COL. 2

ABOvE

COL. 1

SIDES

AND

REAR

COL. 2

ABOvE

COL. 1

SIDES

AND

REAR

COL. 2

(1) 3 1⁄2 in. thick masonry wall without

ventilated air space

-- 24 -- 12 -- 9 -- 6 -- 5

(2) 1⁄2 in. insulation board over 1 in.glass fiber or mineral wool batts

24 18 12 9 9 6 6 5 4 3

(3) 0.024 sheet metal over 1 in. glassfiber or mineral wool batts reinforced with wire on rear facewith ventilated air space

18 12 9 6 6 4 5 3 3 3

(4) 3 1⁄2 in. thick masonry wall withventilated air space

-- 12 -- 6 -- 6 -- 6 -- 6

(5) 0.024 sheet metal with ventilatedair space

18 12 9 6 6 4 5 3 3 2

(6) 1⁄2 in. thick insulation board withventilated air space

18 12 9 6 6 4 5 3 3 3

(7) 0.024 sheet metal with ventilatedair space over 0.024 sheet metalwith ventilated air space

18 12 9 6 6 4 5 3 3 3

(8) 1 in. glass fiber or mineral woolbatts sandwiched between twosheets 0.024 sheet metal with ventilated air space

18 12 9 6 6 4 5 3 3 3

TABLE 5-3REDUCTION OF CLEARANCES WITH SPECIFIED FORMS OF PROTECTION

[NFPA 54: TABLE 10.2.3(b)]

Notes:

1 Reduction of clearances from combustible materials shall not interfere with combustion air, draft hood clearance and relief, and accessibility of servicing.

2 Clearances shall be measured from the outer surface of the combustible material to the nearest point on the surface of the appliance, disregarding any inter-

vening protection applied to the combustible material.3 Spacers and ties shall be of noncombustible material. No spacer or tie shall be used directly opposite the appliance or connector.

4 Where clearance reduction systems use a ventilated air space, adequate provision for air circulation shall be provided as described. [See Figure 5-5 and

Figure 5-6.]5 There shall be not less than one (1) in. (25 mm) between clearance reduction systems and combustible walls and ceilings for reduction systems using a venti-

lated air space.6 Where a wall protector is mounted on a single flat wall away from corners, it shall have a minimum one (1) inch (25 mm) air gap. To provide adequate air

circulation, the bottom and top edges, or only the side and top edges, or edges shall be left open.7 Mineral wool batts (blanket or board) shall have a minimum density of eight (8) lb/ft.3 (128 kg/m3) and a minimum melting point of 1,500°F (816°C).

8 Insulation material used as part of a clearance reduction system shall have a thermal conductivity of 1.0 Btu in./ft2/h-°F (0.144 W/m-K) or less.

9 There shall be not less than (1) inch (25 mm) between the appliance and the protector. In no case shall the clearance between the appliance and the combustible

surface be reduced below that allowed in this table.10 Clearances and thicknesses are minimum; larger clearances and thicknesses are acceptable.

11 Listed single-wall connectors shall be installed in accordance with the terms of their listing and the manufacturer’s instructions.

1 in. = 25.4 mm

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least one (1) inch (25 mm) between the wall protector

and combustible walls and ceilings for clearance,

reduction systems using a ventilated space.

506.7.1.3 Mineral wool batts (blanket or board) shall

have a minimum density of eight (8) lb./ft.3 (3.6

kq/m3) and have a minimum melting point of

1,500°F (816°C).

506.7.1.4 Insulation board used as a part of a clear-

ance-reduction system shall have a thermal conduc-

tivity of 1 Btu in./ft.2 hr°F (0.14 W/m2 hr°C) or less.

Insulation board shall be formed of noncombustible

material.

506.7.1.5 There shall be at least one (1) inch (25 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 5-2.

506.7.2 Duct systems operating at elevated temperatures

above 140°F (60°C) shall have clearances from

combustible building construction or any combustible

material of not less than eighteen (18) inch (457 mm).

506.7.3 Where clearance is reduced by using an airspace

between the combustible wall and the wall protector, air

circulation shall be provided by one of the following

methods.

506.7.3.1 Air circulation shall be permitted

to be provided by leaving all edges of the wall

protector open with at least a one (1) inch (25 mm)

airgap.

506.7.3.2 If the wall protector is mounted on a single

flat wall away from corners, air circulation shall be

permitted to be provided by one of the following:

(A) Leaving top and bottom edges open to circula-

tion by maintaining the one (1) inch (25 mm)

airgap.

(B) Leaving top and both side edges open to circula-

tion by maintaining the (1) inch (25 mm) air gap.

506.7.3.3 Wall protectors that cover two walls in a

corner shall be permitted to be open at the top and

bottom edges with at least a one (1) inch (25 mm) air

gap. [NFPA 91:4.6.3.3]

506.8 Protection from Physical Damage. Ducts installed in

locations where they are subject to physical damage shall be

protected by suitable guards.

506.9 Exhaust Outlets. The termination point for exhaust

ducts discharging to the atmosphere shall be not less than the

following:

506.9.1 Ducts conveying explosive or flammable vapors,

fumes, or dusts: thirty (30) feet (9,144 mm) from prop-

erty line; ten (10) feet (3,048 mm) from openings into

the building, six (6) feet (1,829 mm) from exterior walls

or roofs; thirty (30) feet (9,144 mm) from combustible

walls or openings into the building that are in the direc-

tion of the exhaust discharge; ten (10) feet (3,048 mm)

above adjoining grade.

506.9.2 Other product-conveying outlets: ten (10) feet(3,048 mm) from property line; three (3) feet (914 mm)from exterior wall or roof; ten (10) feet (3,048 mm) fromopenings into the building; ten (10) feet (3,048 mm)above adjoining grade.

Part II – Commercial Hoods and Kitchen Ventilation.

507.0 General Requirements.507.1 Cooking equipment used in processes producing smokeor grease-laden vapors shall be equipped with an exhaust systemthat complies with all the equipment and performance require-ments of this Standard, and all such equipment and perform-ance shall be maintained per this Standard during all periods ofoperation of the cooking equipment. Specifically, the followingequipment shall be kept in good working condition:

(A) Cooking equipment

(B) Hoods

(C) Ducts (if applicable)

(D) Fans

(E) Fire suppression systems

(F) Special effluent or energy control equipment

All airflows shall be maintained. Maintenance andrepairs shall be performed on all components at intervalsnecessary to maintain these conditions.

507.1.1 Electric cooking equipment that has been listedin accordance with UL 197 and provided with integralrecirculation system (also referred to as ductless hoods)or non integral recalculating system listed in accordancewith UL 710B shall not be required to be provided withan exhaust system. [NFPA 96:4.1.1.1*]

507.1.2 The listing evaluation of cooking equipmentcovered by Section 507.1.1 shall demonstrate that thegrease discharge at the exhaust duct of a test hood placedover the appliance shall not exceed 5 mg/m3 when oper-ated with a total airflow of 0.236 cubic meters per second(500 cfm). [NFPA 96:4.1.1.2]

507.1.3 The responsibility for inspection, maintenance, andcleanliness of the ventilation control and fire protection ofthe commercial cooking operations shall be the ultimateresponsibility of the owner of the system provided that thisresponsibility has not been transferred in written form to amanagement company or other party. [NFPA 96:4.1.5]

507.1.4 All solid-fuel cooking equipment shall complywith the requirements of Section 517.0.

507.1.5 Multiple-tenancy applications shall require theconcerted cooperation of design, installation, operation,and maintenance responsibilities by tenants and by thebuilding owner.

507.1.6 All interior surfaces of the exhaust system shallbe accessible for cleaning and inspection purposes.

507.1.7 Cooking equipment used in fixed, mobile, ortemporary concessions, such as trucks, buses, trailers,pavilions, tents, or any form of roofed enclosure, shallcomply with this Standard unless all or part of the instal-lation is exempted by the Authority Having Jurisdiction.

L

A

L

A

]

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507.2 Clearance.

507.2.1 Where enclosures are not required, hoods, greaseremoval devices, exhaust fans, and ducts shall have aclearance of at least eighteen (18) inches (457 mm) tocombustible material, three (3) inches (76 mm) tolimited-combustible material, and zero (0) inches (0 mm)to noncombustible material. [NFPA 96:4.2.1]

507.2.2 Where a hood, duct, or grease removal device islisted for clearances less than those required in Section507.2.1, the listing requirements shall be permitted. [NFPA96:4.2.2]

507.2.3 Clearance Reduction.

507.2.3.1 Where a clearance reduction systemconsisting of 0.013 in. (0.33 mm) (28 gauge) sheetmetal spaced out one (1) inch (25 mm) on noncom-bustible spacers is provided, there shall be a minimumof nine (9) inches (229 mm) clearance to combustiblematerial. [NFPA 96:4.2.3.1]

507.2.3.2 Where a clearance reduction systemconsisting of 0.027 in. (0.69 mm) (22 gauge) sheetmetal on one (1) inch (25 mm) mineral wool batts orceramic fiber blanket reinforced with wire mesh orequivalent spaced out one (1) inch (25 mm) on non-combustible spacers is provided, there shall be aminimum of three (3) inches (76 mm) clearance tocombustible material. [NFPA 96:4.2.3.2]

507.2.3.3 Zero clearance to limited-combustiblematerials shall be permitted where protected bymetal lath and plaster, ceramic tile, quarry tile, othernon-combustible materials or assembly of noncom-bustible materials, or materials and products that arelisted for the purpose of reducing clearance. [NFPA96:4.2.3.3]

507.2.4 Clearance Integrity.

507.2.4.1 In the event of damage, the material orproduct shall be repaired and restored to meet itsintended listing or clearance requirements and shallbe acceptable to the Authority Having Jurisdiction.[NFPA 96:4.2.4.1]

507.2.4.2 In the event of a fire within a kitchenexhaust system, the duct and its enclosure (ratedshaft, factory-built grease duct enclosure, or field-applied grease duct enclosure) shall be inspected byqualified personnel to determine whether the ductand protection method are structurally sound,capable of maintaining their fire protection function,and in compliance with this Standard for continuedoperation. [NFPA 96:4.2.4.2]

507.2.4.3 Protection shall be provided on the wallfrom the bottom of the hood to the floor, or to thetop of the noncombustible material extending to thefloor, to the same level as required in Section507.2.1. [NFPA 96:4.2.4.3]

507.2.4.4 The protection methods for ducts to reduceclearance shall be applied to the combustible orlimited-combustible construction, not to the ductitself. [NFPA 96:4.2.4.4]

507.2.5 Factory-built grease duct enclosures shall beprotected with a through-penetration firestop system clas-sified in accordance with ASTM E 814, Fire Tests ofThrough – Pentration Fire Stops, having an "F" and "T"rating equal to the fire resistance rating of the assemblybeing penetrated from the point at which the duct pene-trates a ceiling, wall or floor to the outlet terminal, and thefactory-built grease duct protection system shall be listedin accordance with UL 2221, Standard for Tests of FireResistive Grease Duct Enclosure Assemblies and installedin accordance with the manufacturer's instructions and thelisting requirements. [NFPA 96:4.3.3, 4.3.3.1, 4.3.3.2]

507.2.6 Field-applied grease duct enclosures shall beprotected with a through penetration firestop system clas-sified in accordance with ASTM E 814, Fire Tests ofThrough – Pentration Fire Stops, having an "F" and "T"rating equal to the fire resistance rating of the assemblybeing penetrated. The surface of the field fabricated greaseduct shall be continuously covered on all sides from thepoint at which the duct enclosure penetrates a ceiling, wallor floor to the outlet terminal, and listed in accordance withASTM E 2336 Standard Test Methods for Fire resistiveGrease Duct Enclosure Systems, and installed in accor-dance with the manufacturer's instructions and the listingrequirements. [NFPA 96:4.3.1, 4.3.1.1, 4.3.1.2]

507.2.7 Field-applied grease duct enclosures and factory-built grease duct enclosures shall demonstrate that theyprovide sufficient mechanical and structural integrity,resiliency, and stability when subjected to expectedbuilding environmental conditions, duct movementunder general operating conditions, and duct movementdue to fire conditions. [NFPA 96:4.3.4]

507.2.7.1 Measures shall be taken to prevent phys-ical damage to any material or product used for thepurpose of reducing clearances.

Exception: When the duct is protected with a field-applied grease duct enclosure or factory-built greaseduct enclosure.

507.2.7.2 The specifications of material, gauge, andconstruction of the duct used in the testing andlisting of field-applied grease duct enclosures andfactory-built grease duct enclosures shall beincluded as minimum requirements in their listingand installation documentation. [NFPA 96:4.3.5]

507.2.7.3 The following clearance options for whichfield-applied grease duct enclosures and factory-built grease duct enclosures have been successfullyevaluated shall be clearly identified in their listingand installation documentation and on their label:[NFPA 96:4.3.6]

(1) Open combustible clearance at manufacturer’srequested dimensions. [NFPA 96:4.3.6(1)]

(2) Closed combustible clearance at manufacturer’srequested dimensions, with or without specifiedventilation. [NFPA 96:4.3.6(2)]

(3) Rated shaft clearance at manufacturer’srequested dimensions, with or without specifiedventilation. [NFPA 96:4.3.6(3)]

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EXHAUST SYSTEMS

507.2.8 A duct shall be permitted to contact noncom-bustible floors, interior walls, and other noncombustiblestructures or supports, but it shall not be in contact formore than fifty (50) percent of its surface area per eachlineal foot of contact length. [NFPA 96:4.4.1]

507.2.8.1 Where duct contact must exceed therequirements of Section 507.2.8, the duct shall beprotected from corrosion. [NFPA 96:4.4.2]

507.2.8.2 Where the duct is listed for zero clearanceto combustibles or otherwise protected with a mate-rial or product listed for the purpose of reducingclearance to zero, the duct shall be permitted toexceed the contact limits of Section 507.2.8 withoutadditional corrosion protection. [NFPA 96:4.4.3]

507.2.9 Clearances between the duct and interior surfacesof enclosures shall meet the requirements of Section 507.2.

507.3 A drawing(s) of the exhaust system installation alongwith a copy of operating instructions for subassemblies andcomponents used in the exhaust system, including electricalschematics, shall be available on the premises.

507.4 If required by the Authority Having Jurisdiction, noti-fication in writing shall be given of any alteration, replace-ment, or relocation of any exhaust or extinguishing system orpart thereof or cooking equipment. Satisfaction shall beprovided to the Authority Having Jurisdiction that thecomplete exhaust system as addressed in this Standard isinstalled and operable in accordance with the approved designand the manufacturer’s instructions.

508.0 Hoods.

508.1 Where Required. Hoods shall be installed at or aboveall commercial-type deep fat fryers, broilers, fry grills, steam-jacketed kettles, hot-top ranges, ovens, barbecues, rotisseries,dishwashing machines, and similar equipment that producescomparable amounts of steam, smoke, grease, or heat in afood-processing establishment. For the purpose of thisSection, a food-processing establishment shall include anybuilding or portion thereof used for the processing of food,but shall not include a dwelling unit.

508.1.1 Construction. The hood or that portion of aprimary collection means designed for collectingcooking vapors and residues shall be constructed of andbe supported by steel not less than 0.043 inch (1.09 mm)(No. 18 MSG) in thickness, stainless steel not less than0.037 inch (0.94 mm) (No. 20 MSG) in thickness, orother approved material of equivalent strength and fireand corrosion resistance.

Exceptions:

(1) Listed exhaust hoods with or without exhaustdampers.

(2) Type II hoods shall be constructed of at least 0.024inch (0.61 mm) (No. 24 gauge steel). Hoodsconstructed of copper shall be of copper sheetsweighing at least twenty-four (24) ounces per squarefoot (7.32 kg/m2). Joints and seams shall be substan-tially tight. Solder shall not be used except for sealinga joint or seam.

All hoods shall be secured in place [OSHPD 1, 2 &

4] to resist the lateral loads given in the CaliforniaBuilding Code, Title 24, Part 2 by noncombustiblesupports.

508.1.2 Wall mounted exhaust hood assemblies shall betight fitting against the back wall as to not permit passageof grease vapor behind the hood, or between the backwall and the hood assembly. [NFPA 96:5.1.13]

508.2 All seams, joints, and penetrations of the hood enclo-sure that direct and capture grease-laden vapors and exhaustgases shall have a liquid-tight continuous external weld to thehood’s lower outermost perimeter. [NFPA 96:5.1.2]

508.2.1 Seams, joints, and penetrations of the hood shallbe permitted to be internally welded, provided that theweld is formed smooth or ground smooth, so as to nottrap grease, and is cleanable. [NFPA 96:5.1.3]

508.2.2 Internal hood joints, seams, filter support frames,and appurtenances attached inside the hood shall besealed or otherwise made grease-tight. [NFPA 96:5.1.4]

508.2.3 Penetrations shall be permitted to be sealed bydevices that are listed for such use and whose presencedoes not detract from the hood’s or duct’s structuralintegrity. [NFPA 96:5.1.5]

508.2.4 Listed exhaust hoods with or without exhaustdampers shall be permitted to be constructed of materialsrequired by the listing. [NFPA 96:5.1.6]

508.2.5 Listed exhaust hoods with or without exhaustdampers shall be permitted to be assembled in accor-dance with the listing requirements. [NFPA 96:5.1.7]

508.2.6 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 5-1. [NFPA 96:5.1.8.1]

FIgURE 5-1TYPICAL SECTION OF EYEBROW-TYPE HOOD.

[NFPA 96:5.1.8.1]

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EXHAUST SYSTEMS

508.2.7 The duct connecting the oven flue(s) to the hoodcanopy shall be connected with a continuous weld orhave a duct-to-duct connection. [See Figure 5-6(a)through Figure 5-6(d)] [NFPA 96:5.1.8.2]

508.2.8 Insulation materials other than electrical insula-tion shall have a flame spread rating of 25 or less whentested in accordance with UL 723, Standard for Test forSurface Burning Characteristics of Building Materials.[NFPA 96:5.1.9]

508.2.9 Adhesives or cements used in the installation ofinsulating materials shall comply with the requirementsof Section 508.2.8, when tested with the specific insu-lating material. [NFPA 96:5.1.10]

508.2.10 Penetrations shall be sealed with listed devicesin accordance with the requirements of Section 508.2.11.[NFPA 96:5.1.11]

508.2.11 Devices that require penetration of the hood,such as pipe and conduit penetration fittings andfasteners, shall be listed in accordance with UL 1978,Standard for Grease Ducts. [NFPA 96:5.1.12]

508.3 Insulation materials other than electrical insulation shallhave a flame-spread rating of twenty-five (25) or less whentested in accordance with UL 723, Standard for Test forSurface Burning Characteristics of Building Materials. Adhe-sives or cements used in the installation of insulating mate-rials shall comply with the preceding requirements whentested with the specific insulating material.

508.4 Hood Size. Hoods shall be sized according to thefollowing calculations and configured to provide for the captureand removal of grease-laden vapors (See Section 511.2.3).

508.4.1 Canopy Size and Location. For canopy-typecommercial cooking hoods, the inside edge thereof shalloverhang or extend a horizontal distance of not less thansix (6) inches (152 mm) beyond the edge of the cookingsurface on all open sides, and the vertical distancebetween the lip of the hood and the cooking surface shallnot exceed four (4) feet (1,219 mm).

Exception: Listed exhaust hoods are to be installed inaccordance with the terms of their listings and the manu-facturer’s installation instructions.

508.4.1.1 Capacity of Hoods. Canopy-typecommercial cooking hoods shall exhaust through thehood a minimum quantity of air determined byapplication of the following formulas:

Where:

A = the horizontal surface area of the hood, insquare feet (m2).

P = that part of the perimeter of the hood that isopen, in feet (mm).

D = distance in feet (mm) between the lower lip ofthe hood and the cooking surface.

Q = quantity of air, in cubic feet per minute (L/s).

When cooking equipment is installed back toback and is covered by a common island-type hood,the airflow required may be calculated using theformula for three sides exposed. Type II hoodairflow requirements shall be in accordance with therequirements for low-temperature appliance hoods.

508.4.1.2 The minimum airflow for solid-fuelcooking equipment, grease-burning charbroilers,and undefined equipment shall be:

Number of Exposed Sides Formula

4 (island or central hood) Q = 300A

3 or less Q = 200A

Alternate formula Q = 100PD

508.4.1.3 Type I hoods when the cooking equipmentincludes high-temperature appliances such as deep-fat fryers:



3 or less Q = 100A


508.4.1.4 Type I hoods where the cooking equip-ment includes medium-temperature appliances suchas rotisseries, grills, and ranges:



3 or less Q = 75A


508.4.1.5 Type I hoods where the cooking equipmentincludes low-temperature appliances such asmedium-to-low-temperature ranges, roasters, roastingovens, pastry ovens, and equipment approved for useunder a Type II hood, such as pizza ovens:



3 or less Q = 50A


Exception: Listed exhaust hoods are to be installedin accordance with the terms of their listing and themanufacturer’s installation instructions.

508.4.2 Capacity for Noncanopy Hoods. In addition toall other requirements for hoods specified in this Section,the volume of air exhausting through a noncanopy-typehood to the duct system shall be not less than 300 cubicfeet per minute per lineal foot (465 L/s per m) of cookingequipment. Listed noncanopy exhaust hoods and filtersshall be sized and installed in accordance with the terms oftheir listing and the manufacturer’s installation instructions.

Exception: Listed hood assemblies designed andinstalled specifically for the intended use.

508.5 Exhaust Hood Assemblies with Integrated Supply-

Air Plenums.

508.5.1 The construction and size of exhaust hoodassemblies with integrated supply air plenums shallcomply with the requirements of Sections 508.1 and508.4. [NFPA 96:5.3.1]

508.5.2 The construction of the outer shell or the innerexhaust shell shall comply with Section 508.1. [NFPA96:5.3.2]

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EXHAUST SYSTEMS

508.5.3 Where the outer shell is welded, the inner shellshall be of grease-tight construction. [NFPA 96:5.3.3]

508.5.4 Fire Dampers.

508.5.4.1 A fire-actuated damper shall be installedin the supply air plenum at each point where asupply air duct inlet or a supply air outlet penetratesthe continuously welded shell of the assembly.[NFPA 96:5.3.4.1]

508.5.4.2 The fire damper shall be listed for suchuse or be part of a listed exhaust hood with orwithout exhaust damper. [NFPA 96:5.3.4.2]

508.5.4.3 The actuation device shall have amaximum temperature rating of 141°C (286°F).[NFPA 96:5.3.4.3]

508.5.5 Supply air plenums that discharge air from theface rather than from the bottom or into the exhaust hoodand that are isolated from the exhaust hood by the contin-uously welded shell extending to the lower outermostperimeter of the entire hood assembly shall not require afire-actuated damper. [NFPA 96:5.3.4.4]

508.6 Listed Hood Assemblies. Listed hood assemblies shallbe installed in accordance with the terms of their listing andthe manufacturer’s instructions. [NFPA 96:5.4.1] Listed hoodassemblies shall be tested in accordance with UL 710,Exhaust Hoods for Commercial Cooking Equipment, orequivalent. [NFPA 96:5.4.2]

508.7 Solid-Fuel Hood Assemblies. Where solid-fuelcooking equipment is to be used, the solid-fuel hood assemblyshall comply with Section 517.0.

508.8 Listed Ultra-Violet Hoods. Listed ultra-violet hoodsshall be installed and maintained in accordance with the termsof their listing and the manufacturer’s instructions. [NFPA96:5.5]

508.9 Exhaust Outlets. An exhaust outlet within an unlistedhood shall be located so as to optimize the capture of partic-ulate matter. Each outlet shall serve not more than a twelve(12) foot (3,658 mm) section of an unlisted hood.

509.0 Grease Removal Devices in Hoods.

509.1 Grease Removal Devices. Listed grease filters, baffles,or other approved grease removal devices for use with commer-cial cooking equipment shall be provided. Listed grease filtersshall be tested in accordance with UL 1046, Grease Filters forExhaust Ducts. Mesh filters shall not be used.

509.2 Installation.

509.2.1 The distance between the grease removal deviceand the cooking surface shall be as great as possible butnot less than eighteen (18) inches (457 mm). [NFPA96:6.2.1.1]

509.2.2 Where grease removal devices are used inconjunction with charcoal or charcoal-type broilers,including gas or electrically heated charbroilers, aminimum vertical distance of four (4) feet (1,219 mm)shall be maintained between the lower edge of the greaseremoval device and the cooking surface. [NFPA96:6.2.1.2]

Exceptions:

(1) Grease removal devices supplied as part of listedhood assemblies shall be installed in accordancewith the terms of the listing and the manufacturer’sinstructions. [NFPA 96:6.2.1.5]

(2) For cooking equipment without exposed flame andwhere flue gases bypass grease removal devices, theminimum vertical distance shall be permitted to bereduced to not less than six (6) inches (152 mm).[NFPA 96:6.2.1.3]

(3) Where a grease removal device is listed for separa-tion distances less than those required in Sections509.2.1 and 509.2.2, the listing requirements shallbe permitted. [NFPA 96:6.2.1.4]

509.2.3 Grease Removal Device Protection. Greaseremoval devices shall be protected from combustion gasoutlets and from direct flame impingement occurringduring normal operation of cooking appliancesproducing high flue gas temperatures, such as deep-fatfryers or upright or high broilers (salamander broilers),where the distance between the grease removal deviceand the appliance flue outlet (heat source) is less thaneighteen (18) inches (457 mm). [NFPA 96:6.2.2.1]

509.2.3.1 This protection shall be permitted to beaccomplished by the installation of a steel or stain-less steel baffle plate between the heat source andthe grease removal device. [NFPA 96:6.2.2.2]

509.2.3.2 The baffle plate shall be sized and locatedso that flames or combustion gases shall travel adistance not less than eighteen (18) inches (457 mm)from the heat source to the grease removal device.[NFPA 96:6.2.2.3]

509.2.3.3 The baffle shall be located not less thansix (6) inches (152 mm) from the grease removaldevices. [NFPA 96:6.2.2.4]

509.2.4 Grease Filters. Grease filters shall be listed andconstructed of steel or listed equivalent material and shallbe of rigid construction that will not distort or crushunder normal operation, handling, and cleaning condi-tions. [NFPA 96: 6.2.3.1 and 6.2.3.2] [SFM] For appli-cations listed in Section 1.11.0 regulated by the Office ofthe State Fire Marshal, grease filters shall be Class Iwhen tested in accordance with the test method in Title24, Part 12, Chapter 12-71, SFM Standard 12-71-1.

509.2.4.1 Filters shall be tight fitting and firmly heldin place and grease filters shall be arranged so thatall exhaust air passes through the grease filters.[NFPA 96:6.2.3.3]

509.2.4.2 Filters shall be easily accessible andremovable for cleaning. [NFPA 96:6.2.3.4]

509.2.4.3 Filters shall be installed at an angle notless than forty-five (45) degrees from the horizontal.[NFPA 96:6.2.3.5]

509.2.4.4 [DPH] Grease filters shall be Class Iwhen tested in accordance with the test method inSFM 12-71-1.

509.2.5 Grease Drip Trays. Filters shall be equipped witha drip tray beneath their lower edges. [NFPA 96:6.2.4.1]

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509.2.5.1 The tray shall be kept to the minimum sizeneeded to collect grease and shall be pitched to draininto an enclosed metal container having a capacitynot exceeding one (1) gallon (3.785 L). [NFPA96:6.2.4.2, and 6.2.4.3]

509.2.6 Grease Filter Orientation. Grease filters thatrequire a specific orientation to drain grease shall beclearly so designated, or the hood shall be constructed sothat filters cannot be installed in the wrong orientation.[NFPA 96:6.2.5]

509.3 Solid-Fuel Grease Removal Devices. Where solid-fuel cooking equipment is provided with grease removaldevices, these devices shall comply with Section 517.0.

510.0 Exhaust Duct Systems.

510.1 General.

510.1.1 Ducts shall not pass through fire walls or firepartitions.

510.1.2 All ducts shall lead as directly as is practicable tothe exterior of the building, so as not to unduly increaseany fire hazard.

510.1.3 Duct systems shall not be interconnected withany other building ventilation or exhaust system.

510.1.4 All ducts shall be installed without forming dips ortraps that might collect residues. In manifold (commonduct) systems, the lowest end of the main duct shall beconnected flush on the bottom with the branch duct. Ductsystems serving a Type I hood shall be so constructed andinstalled that grease cannot become pocketed in any portionthereof, and the system shall slope not less than 1⁄4 inch perlineal foot (21 mm/m) toward the hood or toward anapproved grease reservoir. Where horizontal ducts exceedseventy-five (75) feet (22,860 mm) in length, the slope shallbe not less than one (1) inch per lineal foot (83 mm/m).

510.1.5 Openings required for accessibility shall complywith Section 510.3.

510.1.6 A sign shall be placed on all access panels statingthe following:

ACCESS PANEL––DO NOT OBSTRUCT

510.1.7 Duct bracing and supports shall be of noncom-bustible material, securely attached to the structure anddesigned to carry gravity and lateral loads within the stresslimitations of the Building Code. Bolts, screws, rivets, andother mechanical fasteners shall not penetrate duct walls.

510.1.8 Ducts, Non-Grease. Ducts and plenums servingType II hoods shall be constructed of rigid metallic mate-rials as set forth in Chapter 6. Duct bracing and supportsshall comply with Chapter 6. Ducts subject to positivepressure shall be adequately sealed.

510.2 Clearance.

510.2.1 Clearance between ducts and combustible mate-rials shall be provided in accordance with the require-ments of Section 507.2.

510.2.2 Listed grease ducts shall be installed in accor-dance with the terms of their listings and manufacturers’instructions.

510.3 Openings.

510.3.1 Openings shall be provided at the sides or at thetop of the duct, whichever is more accessible, and atchanges of direction. Openings shall be protected byapproved access panels that comply with Section 510.3.4.5.

Exception: Openings shall not be required in portions ofthe duct that are accessible from the duct entry or discharge.

510.3.2 For hoods with dampers in the exhaust or supplycollar, an access panel for cleaning and inspection shallbe provided in the duct or the hood collar. This accesspanel shall be as close to the hood as possible but shallnot exceed eighteen (18) inches (457 mm).

Exception: Dampers that are accessible from under thehood.

510.3.3 Exhaust fans with ductwork connected to bothsides shall have access for cleaning and inspection withinthree (3) feet (914 mm) of each side of the fan. [NFPA96:7.3.7]

510.3.4 Openings in Ducts. Openings shall conform withSections 510.3.4.1 through 510.3.4.5. [NFPA 96:7.4]

510.3.4.1 Horizontal Ducts. On horizontal ducts, atleast one 20 inch by 20 inch (508 mm x 508 mm)opening shall be provided for personnel entry.[NFPA 96:7.4.1.1]

510.3.4.1.1 Horizontal ducting shall be securedsufficiently to allow for the weight of personnelentry into the duct. Where an opening of this sizeis not possible, openings large enough to permitthorough cleaning shall be provided at twelve(12) feet (3,658 mm) intervals. [NFPA 96:7.4.1.2]

510.3.4.1.2 Openings on horizontal grease ductsystems shall be provided with safe access anda work platform when not easily accessible froma 10 feet (3 m) stepladder. [NFPA 96:7.4.1.3]

510.3.4.1.3 Support systems for horizontalgrease duct systems twenty-four (24) inches(609 mm) and larger in any cross-sectionaldimension shall be designed for the weight ofthe ductwork plus 363 kg (800 lb) at any pointin the duct systems. [NFPA 96:7.4.1.4]

510.3.4.2 On nonlisted ductwork, the edge of theopening shall be not less than 11⁄2 inch (38.1 mm)from all outside edges of the duct or welded seams.[NFPA 96:7.4.1.5]

510.3.4.3 Vertical Ducts. On vertical ductworkwhere personnel entry is possible, access shall beprovided at the top of the vertical riser to accom-modate descent. [NFPA 96:7.4.2.1]

510.3.4.3.1 Where personnel entry is notpossible, adequate access for cleaning shall beprovided on each floor. [NFPA 96:7.4.2.2]

510.3.4.4 Access Panels. Access panels shall be ofthe same material and thickness as the duct (Section510.5.1). Access panels shall have a gasket orsealant that is rated for 1,500°F (815.6°C) and shallbe grease-tight. Fasteners, such as bolts, weld studs,

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EXHAUST SYSTEMS

latches, or wing nuts, used to secure the accesspanels shall be carbon steel or stainless steel andshall not penetrate duct walls.

Exception: Listed grease duct access door assem-blies (access panels) shall be installed in accordancewith their terms of the listings and the manufac-turer's instructions.

510.3.4.5 Openings for installation, servicing, andinspection of listed fire protection system devicesand for duct cleaning shall be provided in ducts andenclosures and shall conform to the requirements ofSection 510.3. Enclosure openings required to reachaccess panels in the ductwork shall be large enoughfor the removal of the access panel.

510.4 Listed Grease Ducts. Listed grease ducts shall beinstalled in accordance with the terms of the listing and themanufacturer’s instructions.

510.5 Other Grease Ducts. Other grease ducts shall complywith the requirements of this Section.

510.5.1 Materials. Ducts shall be constructed of andsupported by carbon steel not less than 0.054 inch (1.37mm) (No. 16 MSG) in thickness or stainless steel not lessthan 0.043 inch (1.09 mm) (No. 18 MSG) in thickness.

510.5.2 Installation.

510.5.2.1 All seams, joints, penetrations, and duct-to-hood collar connections shall have a liquid-tightcontinuous external weld.

Exceptions:

(1) Duct-to-hood collar connections as shown inFigure 5-2 shall be permitted.

(2) Penetrations shall be permitted to be sealed byother listed devices that are tested to be grease-tight and are evaluated under the same condi-tions of fire severity as the hood or enclosure oflisted grease extractors and whose presencedoes not detract from the hood's or duct's struc-tural integrity.

(3) Internal welding shall be permitted, providedthe joint is formed or ground smooth and isreadily accessible for inspection.

510.5.2.2 Overlapping duct connections of either thetelescoping or the bell type shall be used for weldedfield joints, not butt-weld connections. The insideduct section shall always be uphill of the outsideduct section. The difference between inside dimen-sions of overlapping sections shall not exceed 1⁄4inch (6.4 mm). The overlap shall not exceed two (2)inches (50.8 mm) (See Figure 5-3).

FIgURE 5-3

TELESCOPINg AND BELL-TYPE DUCT CONNECTIONS.

[NFPA 96:7.5.5.1(A)(B)]

FIgURE 5-2 PERMITTED DUCT-TO-HOOD COLLAR CONNECTION.

[NFPA 96:7.5.2.2]

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EXHAUST SYSTEMS

510.6 Exterior Installations.

510.6.1 The exterior portion of the ductwork shall bevertical wherever possible and shall be installed andadequately supported on the exterior of a building. Bolts,screws, rivets, and other mechanical fasteners shall notpenetrate duct walls. Clearance of any ducts shall complywith Section 507.2.

510.6.2 All ducts shall be protected on the exterior bypaint or other suitable weather-protective coating or shallbe constructed of noncorrosive stainless steel. Ductworksubject to corrosion shall have minimal contact with thebuilding surface.

510.7 Interior Installations.

510.7.1 In all buildings more than one story in height, andin one-story buildings where the roof-ceiling assembly isrequired to have a fire resistance rating, the ducts shall beenclosed in a continuous enclosure extending from thelowest fire-rated ceiling or floor above the hood, throughany concealed spaces, to or through the roof so as tomaintain the integrity of the fire separations required bythe applicable building code provisions. The enclosureshall be sealed around the duct at the point of penetrationof the lowest fire-rated ceiling or floor above the hood inorder to maintain the fire resistance rating of the enclosureand shall be vented to the exterior of the building throughweather-protected openings.

Exception: The continuous enclosure provisions shallnot be required where a field-applied grease duct enclo-sure or a factory-built grease duct enclosure (See Section510.7.2.3) is protected with a listed duct through-pene-tration protection system equivalent to the fire resistancerating of the assembly being penetrated, and the mate-rials are installed in accordance with the conditions ofthe listing and the manufacturer’s instructions and areacceptable to the Authority Having Jurisdiction.

510.7.2 The enclosure required in Section 510.7.1 shallconform to Sections 510.7.2.1 through 510.7.2.3.

510.7.2.1 If the building is less than four stories inheight, the enclosure wall shall have a fire resistancerating of not less than one (1) hour.

510.7.2.2 If the building is four stories or more inheight, the enclosure wall shall have a fire resistancerating of not less than two (2) hours.

510.7.2.3 Clearance from the duct or the exhaust fanto the interior surface of enclosures of combustibleconstruction shall be not less than eighteen (18)inches (457 mm), and clearance from the duct to theinterior surface of enclosures of noncombustible orlimited-combustible construction shall be not lessthan six (6) inches (152 mm). Provisions forreducing clearances as described in Section 507.2are not applicable to enclosures.

Exception: Clearance from the outer surfaces offield-applied grease duct enclosures and factory-built grease duct enclosures to the interior surfacesof construction installed around them shall be

permitted to be reduced where the field-appliedgrease duct enclosure materials and the factory-builtgrease duct enclosures are installed in accordancewith the conditions of their listings and the manu-facturers’ instructions and are acceptable to theAuthority Having Jurisdiction.

510.7.3 For field-applied grease duct enclosures andfactory-built grease duct enclosures, the materials andproducts shall conform to Sections 510.7.3.1 through510.7.3.3.

510.7.3.1 Field-applied grease duct enclosures andfactory-built grease duct enclosures shall demon-strate that they provide sufficient mechanical andstructural integrity, resiliency, and stability whensubjected to expected building environmental condi-tions, duct movement under general operatingconditions, and duct movement due to interior andexterior fire conditions.

510.7.3.2 Measures shall be taken to prevent phys-ical damage to any covering or enclosure material.Any damage to the covering or enclosure shall berepaired and the covering or enclosure restored tomeet its intended listing and fire-resistive rating andto be acceptable to the Authority Having Jurisdic-tion.

510.7.3.3 In the event of a fire within a kitchenexhaust system, the duct, the enclosure, or thecovering directly applied to the duct shall beinspected by qualified personnel to determinewhether the duct, the enclosure, and the coveringdirectly applied to the duct are structurally sound,capable of maintaining their fire protection func-tions, suitable for continued operation, and accept-able to the Authority Having Jurisdiction.

510.7.4 For listed grease ducts, see Section 510.4.

510.7.5 If openings in the enclosure walls are provided,they shall be protected by approved self-closing firedoors of proper rating. Fire doors shall be installed inaccordance with NFPA 80, Standard for Fire Doors andFire Windows. Openings on other listed materials orproducts shall be clearly identified and labeled accordingto the terms of the listing and the manufacturer's instruc-tions and shall be acceptable to the Authority HavingJurisdiction. The panels shall be readily accessible.

510.7.6 Each duct system shall constitute an individualsystem serving only exhaust hoods in one fire zone onone floor. Multiple ducts shall not be permitted in asingle enclosure unless acceptable to the AuthorityHaving Jurisdiction.

510.8 Termination of Exhaust System.

510.8.1 The exhaust system shall terminate as follows:

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

(B) Through the roof, or to the roof from outside, as inSection 510.8.2, or through a wall, as in Section510.8.3.

>

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EXHAUST SYSTEMS

510.8.2 Rooftop Terminations.

510.8.2.1 Rooftop terminations shall be arranged

with or provided with the following:

(A) A minimum of ten (10) feet (3,048 mm) of

clearance from the outlet to adjacent buildings,

property lines, and air intakes. Where space

limitations absolutely prevent a ten (10) foot

(3,048 mm) horizontal separation from an air

intake, a vertical separation shall be permitted,

with the exhaust outlet being a minimum of

three (3) feet (914 mm) above any air intake

located within ten (10) feet (3,048 mm) hori-

zontally.

(B) The exhaust flow directed up and away from the

surface of the roof and a minimum of forty (40)

inches (1,016 mm) above the roof surface.

(C) The ability to drain grease out of any traps or

low points formed in the fan or duct near the

termination of the system into a collection

container that is noncombustible, closed, rain-

proof, structurally sound for the service to

which it is applied, and will not sustain combus-

tion. A grease collection device that is applied to

exhaust systems shall not inhibit the perform-

ance of any fan.

Exception: Grease containers that are evaluated

for equivalency with the preceding require-

ments and listed as such.

(D) A listed grease duct complying with Section

510.4, or with ductwork complying with

Section 510.5.

(E) A hinged upblast fan supplied with flexible

weatherproof electrical cable and service hold-

open retainer to permit proper inspection and

cleaning that is listed for commercial cooking

equipment, provided the ductwork extends a

minimum of eighteen (18) inches (457 mm)

above the roof surface and the fan discharges a

minimum of forty (40) inches (1,016 mm)

above the roof surface (See Section 511.1.1.).

(F) Other approved fan, provided (1) it meets the

requirements of Sections 510.8.2(C) and 511.1.3,

and (2) its discharge or its extended duct discharge

meets the requirements of Section 510.8.2(B).

510.8.2.2 Listed flexible connectors may be used on

exterior roof locations when required for proper

equipment vibration isolation.

510.8.2.3 Fans shall be provided with safe access

and a work surface for inspection and cleaning.

[NFPA 96:7.8.2.2]

510.8.3 Wall Terminations.

510.8.3.1 Wall terminations shall be arranged with

or provided with the following properties:

(A) Through a noncombustible wall with a minimumof ten (10) feet (3,048 mm) of clearance from theoutlet to adjacent buildings, property lines, gradelevel, combustible construction, or electricalequipment or lines, and the closest point of anyair intake or operable door or window at or belowthe plane of the exhaust termination. The closestpoint of any air intake or operable door orwindow above the plane of the exhaust termina-tion shall be a minimum of ten (10) feet (3,048mm) distant, plus 0.25 feet (0.076m) for each one(1) degree from horizontal, the angle of degreebeing measured from the center of the exhausttermination to the center of the air intake or oper-able door or window (See Figure 5-4).

Exception: A wall termination in a secured areacan be at a lower height above grade if accept-able to the Authority Having Jurisdiction.

(B) The exhaust flow directed perpendicularlyoutward from the wall face or upward.

(C) All the ductwork pitched to drain the greaseback into the hood(s), or with a drain providedto bring the grease back into a container withinthe building or into a remote grease trap.

FIgURE 5-4 EXHAUST TERMINATION DISTANCE FROM FRESH AIR

INTAkE (FAI) OR OPERABLE DOOR OR WINDOW. [NFPA 96:7.8.3]

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EXHAUST SYSTEMS

(D) A listed grease duct complying with Section510.4, or other ducts complying with Section510.5.

(E) An approved fan, provided it meets the require-ments of Sections 510.8.3.1(C) and 511.1.1 or511.1.3.

510.9 Solid-Fuel Duct Systems. Where solid-fuel cookingequipment is to be vented, the duct system shall comply withSection 517.0.

511.0 Air Movement.

511.1 Exhaust Fans for Commercial Cooking Equipment.

Where solid-fuel cooking equipment is to be vented, the ductsystem shall comply with Section 517.0.

511.1.1 Approved upblast fans with motors surroundedby the airstream shall be hinged, supplied with flexibleweatherproof electrical cable and service hold-openretainers, and listed for this use (See Figure 5-5). Instal-lation shall conform to the requirements of Section 510.8.

511.1.2 In-Line Exhaust Fans.

511.1.2.1 In-line fans shall be of the type with themotor located outside the airstream and with beltsand pulleys protected from the airstream by agrease-tight housing. They shall be connected to theexhaust duct by flanges securely bolted as shown inFigures 5-6(a) – 5-6(d), or by a system specificallylisted for such use. Flexible connectors shall not beused. [NFPA 96:8.1.2.1 – 8.1.2.3]

511.1.2.2 If the design or positioning of the fanallows grease to be trapped, a drain directed to areadily accessible and visible grease receptacle, notexceeding one (1) gallon (3.8 L), shall be provided.In-line exhaust fans shall be located in an easily

accessible area of adequate size to allow for serviceor removal. If the duct system connected to the fanis in an enclosure, the space or room in which theexhaust fan is located shall have the same fire resist-ance rating as the enclosure. [NFPA 96:8.1.2.4 –8.1.2.6]

511.1.3 Utility set exhaust fans, if installed at the rooftop

termination point, shall meet the requirements of

Sections 510.8.2.1(A) and 510.8.2.3. If the fan is

installed within the building, it shall be located in an

easily accessible area of adequate size to allow for

service or removal. If 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. The fan shall be connected to the

exhaust duct by flanges securely bolted as shown in

Figures 5-6(a) through 5-6(d) or by a system specifically

listed for such use. Flexible connectors shall not be used.

Exhaust fans shall have a drain directed to a readily

accessible and visible grease receptacle not to exceed one

(1) gallon (3.8 L). [NFPA 96:8.1.3.1 - 8.1.3.6]

511.1.4 Exhaust fan housings shall be constructed of

carbon steel not less than 0.054 inch (1.37 mm) (No. 16

MSG) in thickness or stainless steel not less than 0.043

inch (1.09 mm) (No. 18 MSG) in thickness or, if listed,

constructed in accordance with the terms of the listing.

[NFPA 96:8.1.4]

511.1.5 Openings for cleaning, servicing, and inspection

shall conform to the requirements of Section 510.3.3.

Clearances shall conform to the requirements of Sections

507.2, or 510.7.2.3 if installed within an enclosure.

511.1.6 All wiring and electrical equipment shall comply

with California Electrical Code.

511.2 Airflow.

511.2.1 The air velocity through any duct shall be not

less than 500 feet per minute (152.4 meters per minute)

and not more than 2,500 feet per minute (457.2 m per

minute). [NFPA 96:8.2.1.1]

Exception: Transition duct sections shall be permitted

to be connected to hoods and exhaust fans that do not

meet this velocity, provided that they do not exceed three

(3) feet (914 mm) in length and do not contain traps for

grease.

511.2.2 Transition duct sections that do not exceed three

(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]

511.2.3 Exhaust-air volumes for hoods shall be of suffi-

cient level to provide for capture and removal of grease-

laden cooking vapors. Test data, performance acceptable

to the Authority Having Jurisdiction, or both, shall be

provided, displayed, or both, upon request. [NFPA

96:8.2.2.1, 8.2.2.2]

FIgURE 5-5 UPBLAST FAN CLEARANCES.

[NFPA 96:7.8.2.1]

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EXHAUST SYSTEMS

Exception: Lower exhaust-air volumes shall bepermitted during no-load cooking conditions, providedthey are sufficient to capture and remove flue gases andresidual vapors from cooking equipment.

511.2.4 A hood exhaust fan(s) shall continue to operateafter the extinguishing system has been activated, unlessfan shutdown is required by a listed component of theventilation system or by the design of the extinguishingsystem. It shall not be required to restart the hood exhaustfan when the extinguishing system is activated if theexhaust fan and all cooking equipment served by the fanhad previously been shut down. The hood exhaust fanshall not be required to start upon activation of the extin-guishing system if the exhaust fan and all cooking equip-ment served by the fan have previously been shut down.[NFPA 96:8.2.3.1 - 8.2.3.2]

511.3 Replacement Air. Replacement air quantity shall beadequate to prevent negative pressures in the commercialcooking area(s) from exceeding 0.02 inch water column (4.98kPa). When its fire-extinguishing system discharges, makeupair supplied internally to a hood shall be shut off. [NFPA96:8.3.1 - 8.3.2]

Exception: Compensating hoods shall meet the airflowrequirements specified in Sections 508.4.1.3 through508.4.1.5. Compensating hoods shall extract at least 20percent of their required exhaust airflow from the kitchen area.

511.4 Common Duct (Manifold) Systems.

511.4.1 Master kitchen exhaust ducts that serve multipletenants shall include provision to bleed air from outdoorsor from adjacent spaces into the master exhaust ductwhere required to maintain the necessary minimum airvelocity in the master exhaust duct. [NFPA 96:8.4.1]

511.4.2 The bleed-air ducts shall connect to the top orside of the master exhaust duct. [NFPA 96:8.4.2]

511.4.3 The bleed-air duct shall have a fire damper atleast twelve (12) inches (305 mm) from the exhaust ductconnection. [NFPA 96:8.4.3]

FIgURE 5-6(d)

TYPICAL SECTION OF DUCT-TO-FAN CONNECTION–DIRECT

TO FAN INLET CONE METHOD. [NFPA 96:8.1.2.2(d)]

FIgURE 5-6(c)

TYPICAL SECTION OF DUCT-TO-FAN CONNECTION–

SEALANT METHOD. [NFPA 96: 8.1.2.2(c)]

FIgURE 5-6(b)

TYPICAL SECTION OF DUCT-TO-FAN CONNECTION–OvER-

LAPPINg METHOD. [NFPA 96: 8.1.2.2(b)]

FIgURE 5-6(a)

TYPICAL SECTION OF DUCT-TO-FAN CONNECTION–BUTT

JOINT METHOD. [NFPA 96:8.1.2.2(a)]

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511.4.4 The bleed-air duct shall have the same construc-tion and clearance requirements as the main exhaust ductfrom the connection to the exhaust duct to at least twelve(12) inches (305 mm) on both sides of the fire damper.[NFPA 96:8.4.4]

511.4.5 Each bleed air duct shall have a means ofadjusting (e.g., using volume dampers) the bleed-airquantity. [NFPA 96:8.4.5]

511.4.6 Such means to adjust the bleed air quantity shallbe installed in between the fire damper and the source ofbleed air. [NFPA 96:8.4.6]

511.4.7 A bleed air duct shall not be used for the exhaustof grease-laden vapors and shall be so labeled. [NFPA96:8.4.7]

511.4.8 Unused tenant exhaust connections to the masterexhaust duct that are not used as bleed air connectionsshall be disconnected and sealed at the main duct. [NFPA96:8.4.8]

511.5 Solid-Fuel Air Movement Requirements. Wheresolid-fuel cooking equipment is used, exhaust and replace-ment air also shall comply with Section 517.0.

512.0 Auxiliary Equipment.

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

512.1.1 Where specifically listed for such use or whererequired as part of a listed device or system, dampers inexhaust ducts or exhaust duct systems shall be permitted.[NFPA 96:9.1.2]

512.2 Electrical Equipment.

512.2.1 Wiring systems of any type shall not be installedin ducts. [NFPA 96:9.2.1]

512.2.2 Only where specifically listed for such use shallmotors, lights, and other electrical devices be permittedto be installed in ducts or hoods or located in the path oftravel of exhaust products. [NFPA 96:9.2.2]

512.2.3 Lighting units on hoods shall not be located inconcealed spaces.

512.2.4 Lighting units shall be permitted in concealedspaces where such units are part of a listed exhaust hood.[NFPA 96:9.2.3.3]

512.2.5 Listed lighting units specifically listed for suchuse and installed in accordance with the terms of thelisting shall be permitted to be installed in concealedspaces. [NFPA 96:9.2.3.4]

512.2.6 All electrical equipment shall be installed inaccordance with California Electrical Code, with dueregard to the effects of heat, vapor, and grease on theequipment.

512.3 Other Equipment.

512.3.1 Fume incinerators, thermal recovery units, airpollution control devices, or other devices shall bepermitted to be installed in ducts or hoods or located inthe path of travel of exhaust products where specifically

approved for such use. Downgrading other parts of theexhaust system due to the installation of these approveddevices, whether listed or not, shall not be allowed.[NFPA 96:9.3.1 - 9.3.2]

512.3.2 Any equipment, listed or otherwise, that providessecondary filtration or air pollution control and that isinstalled in the path of travel of exhaust products shallbe provided with an approved automatic fire-extin-guishing system for the protection of the componentsections of the equipment and shall include protection ofthe ductwork downstream of the equipment, whether ornot the equipment is provided with a damper. Filtermedia used in secondary filtration or air pollution controlunits and not complying with Section 509.2.4 shall havefire protection that is adequate for the filter media beingused in accordance with the fire-extinguishing systemmanufacturer’s instructions. If the equipment can be asource of ignition, it shall be provided with appropriatedetection to operate the fire-extinguishing system. [NFPA96:9.3.3, 9.3.3.1, 9.3.4]

512.3.3 Where a cooking exhaust system employs an airpollution control device that recirculates air into thebuilding, the provisions of Section 516.0 shall apply.[NFPA 96:9.3.5]

512.4 Solid-Fuel Auxiliary Equipment. Where solid fuelcooking comprises any part of a cooking operation, additionalprovisions and equipment as described in Section 517.0 shallbe used where required.

513.0 Fire-Extinguishing Equipment.

513.1 General Requirements.

513.1.1 Fire-extinguishing equipment for the protectionof grease removal devices, hood exhaust plenums, andexhaust duct systems shall be provided. [NFPA96:10.1.1]

513.1.2 Cooking equipment that produces grease-ladenvapors (such as, but not limited to, deep-fat fryers,ranges, griddles, broilers, woks, tilting skillets, andbraising pans) shall be protected by fire-extinguishingequipment. [NFPA 96:10.1.2]

513.2 Types of Equipment.

513.2.1 Fire-extinguishing equipment shall include bothautomatic fire-extinguishing systems as primary protec-tion and portable fire extinguishers as secondary backup.[NFPA 96:10.2.1]

513.2.1.1 A placard identifying the use of the extin-guisher as secondary backup means to the automaticfire suppression system shall be conspicuouslyplaced near each portable fire extinguisher in thecooking area. [NFPA 96:10.2.2]

513.2.2 Commercial cooking equipment that producegrease laden vapors shall be provided with a Type IHood, in accordance with this Code, and an automaticfire extinguishing system that is listed and labeled for itsintended use as follows:

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(1) Wet chemical extinguishing system (NFPA 17A, Standardfor Wet Chemical Extinguishing Systems), complying withUL 300, Fire Testing of Fire Extinguishing Systems forProtection of Restaurant Cooking Equipment. All existingdry chemical and wet chemical extinguishing systems shallcomply with UL 300, Fire Testing of Fire ExtinguishingSystems for Protection of Restaurant Cooking Equipment.

(2) Carbon dioxide extinguishing systems (NFPA 12, Stan-dard on Carbon Dioxide Extinguishing Systems).

(3) Automatic fire sprinkler systems (NFPA 13, Standard forthe Installation of Sprinkler Systems).

All existing dry chemical and wet chemical extinguishing systemsshall comply with UL 300, no later than the second requiredservicing of the system following the effective date of this Section.

Exceptions:

(1) Automatic fire-extinguishing equipment provided as partof listed recirculating systems complying with standardUL 710B, Outline of Investigation for RecirculatingExhaust System.

(2) Public schools kitchens, without deep-fat fryers, shall beupgraded to a UL 300, Fire Testing of Fire ExtinguishingSystems for Protection of Restaurant Cooking Equip-ment, compliant system during state funded moderniza-tion projects that are under the jurisdiction of theDivision of the State Architect

513.2.3 In existing systems, when changes in the cookingmedia, positioning, or replacement of cooking equipmentoccur, the fire-extinguishing system shall be made tocomply with Section 513.2.2. [NFPA 96:10.2.3.1]

513.2.4 Modification of Existing Hood Systems.

513.2.4.1 Any abandoned pipe or conduit from aprevious installation shall be removed from within thehood, plenum, and exhaust duct. [NFPA 96:10.2.7.1]

513.2.4.2 Penetrations and holes resulting from theremoval of conduit or piping shall be sealed withlisted or equivalent liquid tight sealing devices.[NFPA 96:10.2.7.2]

513.2.4.3 The addition of obstructions to spraypatterns from the cooking appliance nozzle(s) suchas baffle plates, shelves, or any modification shallnot be permitted. [NFPA 96:10.2.7.3]

513.2.4.4 Changes or modifications to the hazardafter installation of the fire extinguishing systemsshall result in reevaluation of the system design bya properly trained, qualified, and certified person(s).[NFPA 96:10.2.7.4]

513.2.5 Fixed Baffle Hoods with Water Wash. Greaseremoval devices, hood exhaust plenums, and exhaustducts requiring protection in accordance with Section513.1.1 shall be permitted to be protected by a listedfixed baffle hood containing a constant or fire-actuatedwater wash system that is listed and in compliance withUL 300, Fire Testing of Fire Extinguishing Systems forProtection of Restaurant Cooking Equipment, or otherequivalent standards and shall be installed in accordancewith the requirements of their listing. [NFPA 96:10.2.8.1]

513.2.5.1 The water for listed, fixed baffle hoodassemblies shall be permitted to be supplied from

the domestic water supply when the minimum waterpressure and flow are provided in accordance withthe terms of the listing. [NFPA 96:10.2.8.3]

513.2.5.2 The water supply shall be controlled by asupervised water supply control valve. [NFPA96:10.2.8.4]

513.2.5.3 The water wash in the fixed baffle hoodshall be activated by the cooking equipment extin-guishing system. [NFPA 96:10.2.8.5]

513.2.5.4 A water-wash system approved to be usedfor protection of the grease removal device(s), hoodexhaust plenum(s), exhaust duct(s), or combinationthereof shall include instruction and appropriateelectrical interface for simultaneous activation of thewater-wash system from an automatic fire-extin-guishing system, where the automatic fire-extin-guishing system is used for cooking equipmentprotection only. [NFPA 96:10.2.8.6]

513.2.5.5 Where the fire-extinguishing systemprovides protection for the cooking equipment,hood, and duct, activation of the water wash shallnot be required. [NFPA 96:10.2.8.7]

513.2.5.6 The water required for listed automaticfire-extinguishing systems shall be permitted to besupplied from the domestic water supply where theminimum water pressure and flow are provided inaccordance with the terms of the listing. The watersupply shall be controlled by a supervised watersupply control valve. [NFPA 96:10.2.9]

513.2.6 Water Valve Supervision. Valves controllingthe water supply to listed fixed baffle hood assemblies,automatic fire-extinguishing systems, or both shall belisted indicating type of valve and shall be supervisedopen by one of the following methods:

(1) Central station, proprietary, or remote station alarmservice.

(2) Local alarm service that will cause the sounding ofan audible signal at a constantly attended point.

(3) Locking valves open.

(4) Sealing of valves and approved weekly recordedinspection. [NFPA 96:10.2.10]

513.3 Simultaneous Operation. Fixed-pipe extinguishingsystems in a single hazard area shall be arranged for simulta-neous automatic operation upon actuation of anyone of thesystems. [NFPA 96:10.3.1]

513.3.1 Simultaneous operation shall not be requiredwhere the fixed pipe extinguishing system is an automaticsprinkler system. [NFPA 96:10.3.2]

513.3.2 Simultaneous operation shall not be requiredwhere dry or wet chemical systems are permitted to beused to protect common exhaust ductwork by the methodsspecified in NFPA 17A, Wet Chemical ExtinguishingSystems.

513.4 Fuel Shutoff.

513.4.1 Upon activation of any fire-extinguishing system fora cooking operation, all sources of fuel and electric powerthat produce heat to all equipment requiring protection bythat system shall automatically shut off. [NFPA 96:10.4.1]

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Exception: Solid-fuel cooking operations.

513.4.2 Steam supplied from an external source shall notbe required to automatically shut off. [NFPA 96:10.4.2]

513.4.3 Any gas appliance not requiring protection, butlocated under the same ventilating equipment, shall alsoautomatically shut off upon activation of any extin-guishing system. [NFPA 96:10.4.3]

513.4.4 Shutoff devices shall require manual reset.[NFPA 96:10.4.4]

513.5 Manual Activation.

513.5.1 A readily accessible means for manual activationshall be located between forty-two (42) inches and forty-eight (48) inches (1,067 mm and 1,219 mm) above thefloor, located in a path of exit or egress, and clearly iden-tify the hazard protected. A manual actuation device shallbe located a minimum of ten (10) feet (3 m) when possibleand a maximum of twenty (20) feet (6 m) from theprotected kitchen appliance(s) within the path of egress.Manual actuation using a cable-operated pull station shallnot require more than forty (40) pounds (178 N) of force,with a pull movement not to exceed fourteen (14) inches(356 mm) to actuate the fire suppression system. The auto-matic and manual means of system activation external tothe control head or releasing device shall be separate andindependent of each other so that failure of one will notimpair the operation of the other. [NFPA 96:10.5.1 – 10.5.2]

513.5.2 The manual means of system activation shall be

permitted to be common with the automatic means if the

manual activation device is located between the control

head or releasing device and the first fusible link. [NFPA

96:10.5.3]

513.5.3 An automatic sprinkler system shall not require

a manual means of system activation. [NFPA 96:10.5.4]

513.5.4 The means for manual actuator(s) shall be

mechanical or rely on electrical power for actuation.

[NFPA 96:10.5.5]

513.5.5 Electrical power shall be permitted to be used

for manual activation if a standby power supply is

provided or if supervision is provided in accordance with

Section 513.7. [NFPA 96:10.5.6]

513.6 System Annunciation.

513.6.1 Upon activation of an automatic fire extin-

guishing system, an audible alarm or visual indicator

shall be provided to show that the system has activated.

[NFPA 96:10.6.1]

513.6.2 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]

513.7 System Supervision.

513.7.1 Where electrical power is required to operate the

automatic fire-extinguishing system, it shall be moni-

tored by a supervisory alarm, with a standby power

supply provided. [NFPA 96:10.7.1]

513.7.2 System supervision shall not be required wherean automatic fire-extinguishing system(s) includes auto-matic mechanical detection and actuation as a backupdetection system. [NFPA 96:10.7.2]

513.7.3 System supervision shall not be required wherea fire-extinguishing system(s) is interconnected or inter-locked with the cooking equipment power source(s) sothat if the fire extinguishing system becomes inoperabledue to power failure, all sources of fuel or electric powerthat produce heat to all cooking equipment serviced bythat hood shall automatically shut off. [NFPA 96:10.7.3]

513.7.4 System supervision shall not be required wherean automatic fire-extinguishing system, including auto-matic mechanical detection and actuation, is electricallyconnected to a listed fire-actuated water-wash system forsimultaneous operation of both systems. [NFPA96:10.7.4]

513.8 Special Design and Application.

513.8.1 Hoods containing automatic fire extinguishingsystems are protected areas; therefore, these hoods arenot considered obstructions to overhead sprinklersystems and shall not require floor coverage underneath.[NFPA 96:10.8.1]

513.8.2 A single listed detection device, listed with theextinguishing system, shall be permitted for more thanone (1) appliance when installed in accordance with theterms of the listing. [NFPA 96:10.8.2]

513.9 Review and Certification.

513.9.1 Where required, complete drawings of thesystem installation, including the hood(s), exhaustduct(s), and appliances, along with the interface of thefire-extinguishing system detectors, piping, nozzles, fuelshutoff devices, agent storage container(s), and manualactuation device(s), shall be submitted to the AuthorityHaving Jurisdiction. [NFPA 96:10.9.1]

513.10 Installation Requirements.

513.10.1 Installation of systems shall be performed onlyby persons properly trained and qualified to install thespecific system being provided. The installer shallprovide certification that the installation is in agreementwith the terms of the listing and the manufacturer'sinstructions and/or approved design. [NFPA 96:10.9.2]

513.11 Portable Fire Extinguishers.

513.11.1 Portable fire extinguishers shall be installed inkitchen cooking areas in accordance with Chapter 3, Title19 California Code of Regulations. Such extinguishersshall use agents that specify upon contact with hotgrease, such as sodium bicarbonate and potassium bicar-bonate dry chemical and potassium carbonate solutions.Class B gas-type portables such as CO2 and halon shallnot be permitted in kitchen cooking areas. Manufac-turer’s recommendations shall be followed.

513.11.1.1 Portable fire extinguishers listed specif-ically for use in the kitchen cooking areas shall also

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be permitted.

513.11.2 Other fire extinguishers in the kitchen area shallbe installed in accordance with Chapter 3, Title 19 Cali-fornia Code of Regulations.

513.12 Solid-Fuel Fire-Extinguishing Equipment. Wheresolid-fuel cooking equipment is served by fire extinguishingequipment, the provisions of Section 517.0 shall apply.

514.0 Procedures for the Use and Maintenance of Equip-ment.

514.1 Operating Procedures.

514.1.1 Exhaust systems shall be operated whenevercooking equipment is turned on. [NFPA 96:11.1.1]

514.1.2 Filter-equipped exhaust systems shall not beoperated with filters removed. [NFPA 96:11.1.2]

514.1.3 Openings provided for replacing air exhaustedthrough ventilating equipment shall not be restricted bycovers, dampers, or any other means that would reduce theoperating efficiency of the exhaust system. [NFPA 96:11.1.3]

514.1.4 Instructions for manually operating the fire-extinguishing system shall be posted conspicuously inthe kitchen and shall be reviewed periodically withemployees by the management. [NFPA 96:11.1.4]

514.1.5 Listed exhaust hoods shall be operated in accor-dance with the terms of their listings and the manufac-turer's instructions. [NFPA 96:11.1.5]

514.1.6 Cooking equipment shall not be operated whileits fire-extinguishing system or exhaust system is nonop-erational or otherwise impaired. [NFPA 96:11.1.6]

514.1.7 Secondary filtration and pollution control equip-ment shall be operated in accordance with the terms of itslisting and the manufacturer's recommendations. [NFPA96:11.1.7]

514.1.8 Inspection and maintenance of equipmentallowed in Section 512.3.1 shall be conducted by prop-erly trained and qualified persons at a frequency deter-mined by the manufacturer's instructions or equipmentlisting. [NFPA 96:11.1.8]

514.2 Inspection. Maintenance of the fire-extinguishingsystems and listed exhaust hoods containing a constant or fire-activated water system that is listed to extinguish a fire in thegrease removal devices, hood exhaust plenums, and exhaustducts shall be made by properly trained, qualified, and certi-fied person(s) or company acceptable to the Authority HavingJurisdiction at least every six (6) months. [NFPA 96:11.2.1]

514.2.1 All actuation components, including remotemanual pull stations, mechanical or electrical devices,detectors, actuators, and fire-actuated dampers, shall bechecked for proper operation during the inspection inaccordance with the manufacturer's listed procedures. Inaddition to these requirements, the specific inspectionrequirements of the applicable NFPA standard shall alsobe followed. [NFPA 96-04:11.2.2 - 11.2.3]

514.2.2 Fusible links (including fusible links on firedamper assemblies) and automatic sprinkler heads shall

be replaced at least semiannually, or more frequently ifnecessary where required by the manufacturer. [NFPA96-04:11.2.4]

514.2.3 The year of manufacture and the date of instal-

lation of the fusible links shall be marked on the system

inspection tag. The tag shall be signed or initialed by the

installer. [NFPA 96:11.2.5]

Other detection devices not including fusible links

and automatic sprinklers shall be serviced or replaced in

accordance with the manufacturer’s recommendations.

[NFPA 96-04:11.2.6]

514.2.4 Where automatic bulb-type sprinklers or spray

nozzles are used and annual examination shows no

buildup of grease or other material on the sprinkler or

spray nozzles, annual replacement shall not be required.

[NFPA 96:11.2.7]

514.2.5 If required, certificates of inspection and main-

tenance shall be forwarded to the Authority Having Juris-

diction. [NFPA 96:11.2.8]

514.3 Inspection for Grease Buildup.

514.3.1 The entire exhaust system shall be inspected for

grease buildup by a properly trained, qualified, and certi-

fied company or person(s) acceptable to the Authority

Having Jurisdiction in accordance with Table 5-4.

514.4 Cleaning of Exhaust Systems.

514.4.1 Upon inspection, if the exhaust system is foundto be contaminated with deposits from grease-ladenvapors, the contaminated portions of the exhaust systemshall be cleaned by a properly trained, qualified, andcertified company or person(s) acceptable to theAuthority Having Jurisdiction. [NFPA 96:11.6.1]

514.4.2 Hoods, grease removal devices, fans, ducts, andother appurtenances shall be cleaned to removecombustible contaminant's prior to surfaces becomingheavily contaminated with grease or oily sludge. [NFPA96:11.6.2]

514.4.3 At the start of the cleaning process, electricalswitches that could be activated accidentally shall be

TYPE OR vOLUME OF COOkINg FREqUENCY FREqUENCY

Systems serving solid-fuel cooking operations

Monthly

Systems serving high-volume cooking opera-tions such as 24-hour cooking, charbroiling, or wok cooking

Quarterly

Systems serving moderate-volume cookingoperations

Semi-annually

Systems serving low-volume cooking opera-tions, such as churches, day camps, seasonalbusinesses, or senior centers.

Annually

TABLE 5-4

EXHAUST SYSTEM INSPECTION SCHEDULE

[NFPA 96: TABLE 11.4]

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locked out. [NFPA 96:11.6.3]

514.4.4 Components of the fire suppression system shallnot be rendered inoperable during the cleaning process.[NFPA 96:11.6.4]

514.4.5 Fire-extinguishing systems shall be permitted tobe rendered inoperable during the cleaning processwhere serviced by properly trained and qualified persons.[NFPA 96:11.6.5]

514.4.6 Flammable solvents or other flammable cleaningaids shall not be used. [NFPA 96:11.6.6]

514.4.7 Cleaning chemicals shall not be applied onfusible links or other detection devices of the automaticextinguishing system. [NFPA 96:11.6.7]

514.4.8 After the exhaust system is cleaned, it shall notbe coated with powder or other substance. [NFPA96:11.6.8]

514.4.9 When cleaning procedures are completed, allaccess panels (doors) and cover plates shall be restoredto their normal operational condition. [NFPA 96:11.6.9]

514.4.10 When an access panel is removed, a servicecompany label or tag preprinted with the name of thecompany and giving the date of inspection or cleaningshall be affixed near the affected access panels. [NFPA96:11.6.10]

514.4.11 Dampers and diffusers shall be positioned forproper airflow. [NFPA 96:11.6.11]

514.4.12 When cleaning procedures are completed, allelectrical switches and system components shall bereturned to an operable state. [NFPA 96:11.6.12]

514.4.13 When an exhaust cleaning service is used, acertificate showing the name of the servicing company,the name of the person performing the work, and the dateof inspection or cleaning shall be maintained on thepremises. [NFPA 96:11.6.13]

514.4.14 After cleaning or inspection is completed, theexhaust cleaning company and the person performing thework at the location shall provide the owner of thesystem with a written report that also specifies areas thatwere inaccessible or not cleaned. [NFPA 96:11.6.14]

514.4.15 Where required, certificates of inspection andcleaning and reports of areas not cleaned shall besubmitted to the Authority Having Jurisdiction. [NFPA96:11.6.15]

515.0 Minimum Safety Requirements for Cooking Equip-ment.

515.1 Cooking Equipment.

515.1.1 Cooking equipment shall be approved based onone of the following criteria:

(A) Listings by a testing laboratory.

(B) Test data acceptable to the Authority Having Juris-diction. [NFPA 96:12.1.1]

515.1.2 Installation.

515.1.2.1 All listed appliances shall be installed inaccordance with the terms of their listings and the

manufacturer's instructions. [NFPA 96:12.1.2.1]

515.1.2.2 Cooking appliances requiring protection

shall not be moved, modified, or rearranged without

prior reevaluation of the fire-extinguishing system

by the system installer or servicing agent, unless

otherwise allowed by the design of the fire-extin-

guishing system. [NFPA 96:12.1.2.2]

515.1.2.3 The fire-extinguishing system shall not

require re-evaluation where the cooking appliances

are moved to perform maintenance and cleaning

provided the appliances are returned to approved

design location prior to cooking operations, and any

disconnected fire-extinguishing system nozzles

attached to the appliances are reconnected in accor-

dance with the manufacturer’s listed design manual.

[NFPA 96:12.1.2.3]

515.1.2.4 All deep-fat fryers shall be installed with

at least a sixteen (16) inch (406 mm) space between

the fryer and surface flames from adjacent cooking

equipment. [NFPA 96:12.1.2.4]

515.1.2.5 Where a steel or tempered glass baffle

plate is installed at a minimum eight (8) inches (203

mm) in height between the fryer and surface flames

of the adjacent appliance, the requirement for a

sixteen (16) inch (406 mm) space shall not apply.

[NFPA 96:12.1.2.5]

515.1.2.6 If the fryer and the surface flames are at

different horizontal planes, the minimum height of

eight (8) inches (203 mm) shall be measured from

the higher of the two. [NFPA 96:12.1.2.5.1]

515.2 Operating Controls. 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 when

the fat temperature reaches 475°F (246°C) at one (1) inch (25

mm) below the surface. [NFPA 96:12.2]

515.3 Cooking Equipment Maintenance.

515.3.1 An inspection and servicing of the cooking

equipment shall be made at least annually by properly

trained and qualified persons. [NFPA 96:11.5.1]

515.3.2 Cooking equipment that collects grease below

the surface, behind the equipment, or in cooking equip-

ment flue gas exhaust, such as griddles or charbroilers,

shall be inspected and, if found with grease accumula-

tion, cleaned by a properly trained, qualified, and certi-

fied person acceptable to the Authority Having

Jurisdiction. [NFPA 96:11.5.2]

516.0 Recirculating Systems.

516.1 General Requirements. Recirculating systems

containing or for use with appliances used in processes

producing smoke or grease-laden vapors shall be equipped

with components complying with the following:

(A) The clearance requirements of Section 507.2.

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(B) A hood complying with the requirements of Section

508.0.

(C) Grease removal devices complying with Section 509.0.

(D) The air movement requirements of Sections 511.2.1 and511.2.2.

(E) Auxiliary equipment (such as particulate and odorremoval devices) complying with Section 512.0.

(F) Fire-extinguishing equipment complying with therequirements of Section 513.0.

Exception: References to ducts in Sections 513.1.1 and513.5.1.

(G) The use and maintenance requirements of Section 514.0.

(H) The minimum safety requirements of Section 515.0.

(I) All the requirements of this Chapter. [NFPA 96:13.1]

516.2 Design Restrictions. All recirculating systems shallcomply with Section 516.2. [NFPA 96:13.2]

516.2.1 Only gas- or electrically fueled cooking appli-ances shall be used. Gas-fueled appliances shall not havethe combustion flue outlet(s) directly connected to therecirculating system. Gas-fueled appliances shall have aminimum eighteen (18) inch (457 mm) clearance fromthe flue outlet to the filter inlet in accordance withSection 509.2.3 and shall meet the installation require-ments of NFPA 54, National Fuel Gas Code, or NFPA58, Liquefied Petroleum Gas Code. [NFPA 96:13.2.1 –13.2.3]

516.2.2 Recirculating systems shall be listed with atesting laboratory. The recirculating system listing shallinclude integral fire protection for recirculating hoods,including canopy type [NFPA 96:13.2.4.1]

516.2.3 Cooking appliances that require protection andthat are under a recirculating hood shall be protected byeither the integral fire protection system for the hood ora system in accordance with Section 513.0. [NFPA96:13.2.4.2]

516.2.4 A recirculating system shall not use cookingequipment that exceeds that recirculating system'slabeled maximum limits for that type of equipment,stated in maximum energy input, maximum cookingtemperature, and maximum square area of cookingsurface or cubic volume of cooking cavity. [NFPA96:13.2.6]

516.2.5 The listing label shall show the type(s) ofcooking equipment tested and the maximum limits spec-ified in Section 516.2.4. [NFPA 96:13.2.7]

516.2.6 A fire-actuated damper shall be installed at theexhaust outlet of the system. The actuation device shallhave a maximum temperature rating of 375°F (190°C).[NFPA 96:13.2.8, 13.2.10]

516.2.7 No electrical wiring shall be installed in the inte-rior sections of the hood plenum that might becomeexposed to grease.

Exception: As permitted by the California ElectricalCode.

516.2.8 The power supply of any electrostatic precipi-tator (ESP) shall be of the "cold spark," ferro-resonanttype in that the voltage falls off as the current draw of ashort increases. [NFPA 96:13.2.11]

516.2.9 Listing evaluation shall include the following:

(A) Capture and containment of vapors at published andlabeled airflows.

(B) Grease discharge at the exhaust outlet of the systemnot to exceed an average of 5 mg/m3 of exhausted airsampled from that equipment at maximum amountof product that is capable of being processed over acontinuous 8-hour test per EPA Test Method 202,Determination of Condensable Particulate Emis-sions for Stationary Sources, with the system oper-ating at its minimum listed airflow.

(C) Listing and labeling of clearance to combustiblesfrom all sides, top, and bottom.

(D) Electrical connection in the field in accordance withthe California Electrical Code.

(E) Interlocks on all removable components that lie in thepath of airflow within the unit to ensure that they arein place during operation of the cooking appliance.

516.3 Interlocks. The recirculating system shall be providedwith interlocks of all critical components and operations asindicated in Sections 516.3.1 through 516.3.4 such that, if anyof these interlocks are interrupted, the cooking appliance shallnot be able to operate. [NFPA 96:13.3.1]

516.3.1 All closure panels encompassing airflow sectionsshall have interlocks to ensure the panels are in place andfully sealed.[NFPA 96:13.3.2]

516.3.2 Each filter component (grease and odor) shallhave an interlock to prove the component is in place.[NFPA 96:13.3.3]

516.3.3 ESP Interlocks.

516.3.3.1 Each ESP shall have a sensor to prove itsperformance is as designed, with no interruption ofthe power to exceed two (2) minutes. [NFPA96:13.3.4.1]

516.3.3.2 The sensor shall be a manual reset deviceor circuit. [NFPA 96:13.3.4.2]

516.3.4 An airflow switch or transducer shall beprovided after the last filter component to ensure that aminimum airflow is maintained. This device opens theinterlock circuit when the airflow falls twenty-five (25)percent below the system's normal operating flow or ten(10) percent below its listed minimum rating, whicheveris lower. This switch or transducer shall be a manual resetdevice or circuit. [NFPA 96:13.3.5]

516.4 Location and Application Restrictions. The locationof recirculating systems shall be approved by the AuthorityHaving Jurisdiction. Items to be reviewed in the fire riskassessment shall include, but not be limited to, life safety,combustibility of surroundings, proximity to air vents, andtotal fuel load. [NFPA 96:13.4]

516.5 Additional Fire Safety Requirements.

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EXHAUST SYSTEMS

516.5.1 In addition to the appliance nozzle(s), a recircu-lating system shall be listed with the appropriate fireprotection for grease filters, grease filtration, odor filtra-tion units, and ductwork where applicable. [NFPA96:13.5.1]

516.5.2 In addition to any other fire-extinguishing system

actuation device, there shall be a fire-extinguishing

system actuation device installed downstream of any

ESP.[NFPA 96:13.5.2]

516.5.3 The requirements of Section 513.6 shall also

apply to recirculating system locations. [NFPA 96:13.5.3]

516.6 Use and Maintenance.

516.6.1 Automatic or manual covers on cooking appli-

ances, especially fryers, shall not interfere with the appli-

cation of the fire suppression system.[NFPA 96:13.6.1]

516.6.2 All filters shall be cleaned or replaced in accor-

dance with the manufacturer's instructions. [NFPA

96:13.6.2]

516.6.3 All ESPs shall be cleaned a minimum of once

per week following manufacturer's cleaning instructions.

[NFPA 96:13.6.3]

516.6.4 The entire hood plenum and the blower section

shall be cleaned a minimum of once every three (3)

months. [NFPA 96:13.6.4]

516.6.5 Inspection and testing of the total operation and

all safety interlocks in accordance with the manufac-

turer's instructions shall be performed by qualified

service personnel a minimum of once every six (6)

months, or more frequently if required. [NFPA 96:13.6.5]

516.6.6 Fire-extinguishing equipment shall be inspected

in accordance with Section 514.2. [NFPA 96:13.6.6]

516.6.7 A signed and dated log of maintenance as

performed in accordance with Sections 516.6.4 and

516.6.5 shall be available on the premises for use by the

Authority Having Jurisdiction. [NFPA 96:13.6.7]

517.0 Solid-Fuel Cooking Operations.

517.1 Venting Application. Venting requirements of solid-

fuel cooking operations shall be determined in accordance

with Sections 517.1.1 through 517.1.6.

517.1.1 Where solid-fuel cooking equipment is required

by the manufacturer to have a natural draft, the vent shall

comply with Section 517.4.

517.1.2 Where the solid-fuel cooking equipment has a

self-contained top, is the only 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 comply

with Sections 517.4 and 517.6.

517.1.3 Where the solid-fuel cooking equipment is

located in a space with other vented equipment, all

vented equipment shall have an exhaust system inter-

locked with a makeup-air system for the space as per

Section 517.6.

517.1.4 Natural draft ventilation systems and power-

exhausted ventilation systems shall comply with Sections

517.3, 517.4, and 517.6.

517.1.5 Where a solid-fuel cooking appliance allowseffluent to escape from the appliance opening, thisopening shall be covered by a hood and an exhaustsystem that meets the requirements of Sections 517.3,517.4, and 517.6.

517.1.6 Solid-fuel cooking operations shall have sparkarresters to minimize the passage of airborne sparks andembers into plenums and ducts. Where the solid-fuelcooking operation is not located under a hood, a sparkarrester shall be provided to minimize the passage ofsparks and embers into flues and chimneys.

517.2 Location of Appliances.

517.2.1 Every appliance shall be located with respect tobuilding construction and other equipment so as topermit access to the appliance.

517.2.2 Solid-fuel cooking appliances shall not beinstalled in confined spaces.

Exception: Solid-fuel cooking appliances listed forinstallation in confined spaces shall be installed in accor-dance with the terms of the listing and the manufacturer'sinstructions.

517.2.3 Solid-fuel cooking appliances shall not beinstalled in any location where gasoline or any otherflammable vapors or gases are likely to be present.

517.3 Hoods for Solid-Fuel Cooking.

517.3.1 Hoods shall be sized and located in a mannercapable of capturing and containing all of the effluentdischarging from the appliances. The hood and its exhaustsystem shall comply with the provisions of the Code.

517.3.2 All solid-fuel cooking equipment served by hoodand duct systems shall be separate from all other exhaustsystems.

Exception: Cooking equipment not requiring automaticfire-extinguishing equipment (as per the provisions ofSection 510.0) shall be permitted to be installed under acommon hood with solid-fuel cooking equipment that isserved by a duct system separate from all other exhaustsystems.

517.4 Exhaust Systems for Solid-Fuel Cooking. Where ahood is not required, in buildings where the duct system isthree (3) stories or less in height, a duct complying withSection 510.0 shall be provided.

517.4.1 If a hood is used, the duct system shall conformwith the Section 510.0.

517.4.2 A listed or approved grease duct system shall beprovided for solid-fuel cooking exhaust systems that arefour (4) stories in height or greater.

517.4.3 Where a hood is used, the duct system shallconform with the requirements of Section 510.0.

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EXHAUST SYSTEMS

517.4.4 Wall terminations of solid-fuel exhaust systemsshall be prohibited.

517.5 Grease Removal Devices for Solid-Fuel Cooking.Grease removal devices shall be constructed of steel or stain-less steel or be approved for solid-fuel cooking.

517.5.1 If airborne sparks and embers can be generated bythe solid-fuel cooking operation, spark arrester devicesshall be used prior to the grease removal device to mini-mize the entrance of these sparks and embers into thegrease removal device and into the hood and duct system.

517.5.2 Filters shall be a minimum of four (4) feet (1.2m) above the appliance cooking surface.

517.6 Air Movement for Solid-Fuel Cooking. Exhaust systemrequirements shall comply with the provisions of the Code forhooded operation or shall be installed in accordance with themanufacturer's recommendation for unhooded applications.

517.6.1 A replacement or makeup-air system shall beprovided to ensure a positive supply of replacement air atall times during cooking operations.

517.6.2 Makeup-air systems serving solid-fuel cookingoperations shall be interlocked with the exhaust-airsystem and powered, if necessary, to prevent the spacefrom attaining a negative pressure while the solid-fuelappliance is in operation.

517.7 Fire-Extinguishing Equipment for Solid-FuelCooking.

517.7.1 Approved fire-extinguishing equipment shall beprovided to protect all solid-fuel-burning cooking appli-ances that might be a source of ignition of grease in thehood, grease removal device, or duct.

Exception: If acceptable to the Authority Having Juris-diction, solid-fuel-burning cooking appliances constructedof solid masonry or reinforced portland or refractorycement concrete and vented in accordance with NFPA211, Standard for Chimneys, Fireplaces, Vents, and SolidFuel–Burning Appliances, Chapters 3 and 4, shall notrequire fixed automatic fire-extinguishing equipment.

517.7.2 Approved fire-extinguishing equipment shall beprovided for the protection of grease removal devices,hoods, and duct systems.

Exception: If acceptable to the Authority Having Juris-diction, solid-fuel-burning cooking appliancesconstructed of solid masonry or reinforced portland orrefractory cement concrete and vented in accordancewith NFPA 211, Standard for Chimneys, Fireplaces,Vents, and Solid Fuel–Burning Appliances, Chapters 3and 4, shall not require automatic fire-extinguishingequipment.

517.7.3 Approved fire-extinguishing equipment forsolid-fuel-burning cooking appliances, where required,shall comply with NFPA 211, Standard for Chimneys,Fireplaces, Vents, and Solid Fuel–Burning Appliancesand shall be comprised of water-based agents.

517.7.4 Fire-extinguishing equipment shall be rated anddesigned to extinguish solid-fuel cooking fires, in accor-dance with the manufacturer's recommendations. The

fire-extinguishing equipment shall be of sufficient sizeto totally extinguish fire in the entire hazard area andprevent reignition of the fuel.

517.7.5 All solid-fuel appliances (whether or not under ahood) with fireboxes of five (5) ft.3 (0.14 m3) volume orless shall at least have a listed 2-A rated water-type fireextinguisher or a 1.6 gal (6 L) wet chemical fire extin-guisher listed for Class K fires in accordance with NFPA10, Portable Fire Extinguishers, in the immediatevicinity of the appliance. [NFPA 96:14.7.8]

517.7.6 Solid-fuel appliances with fireboxes exceedingfive (5) ft.3 (0.14 m3) shall be provided with a fixed-water-pipe system with a hose in the immediate vicinityof the appliance. The hose shall be equipped with anadjustable nozzle capable of producing a fine to mediumspray or mist. The nozzle shall be of the type that cannotproduce a straight stream. The system shall have aminimum operating pressure of forty (40) psi (275.8 kPa)and shall provide a minimum of five (5) gpm. [NFPA96:14.7.9.1 – 14.7.9.2]

517.7.7 Fire suppression for fuel storage areas shallcomply with Section 517.8.

517.7.8 In addition to the requirements of Section517.7.5 or 517.7.6, where any solid-fuel cooking appli-ance is also provided with auxiliary electric, gas, oil, orother fuel for ignition or supplemental heat and the appli-ance is also served by any portion of a fire-extinguishingsystem complying with Section 513.0, such auxiliary fuelshall be shut off upon actuation of the fire-extinguishingsystem.

517.8 Other Safety Requirements.

517.8.1 Metal-fabricated solid-fuel cooking appliancesshall be listed for the application where produced in prac-tical quantities or shall be approved by the AuthorityHaving Jurisdiction. When listed, they shall be installedin accordance with the terms of their listings and withthe applicable requirements of this Standard.

517.8.2 Site-built solid-fuel cooking appliances shall besubmitted for approval to the Authority Having Jurisdic-tion before being considered for installation. All unitsshall be installed, operated, and maintained in accordancewith the approved terms of the manufacturer's instruc-tions and any additional requirements set forth by theAuthority Having Jurisdiction.

517.8.3 Except for the spark arrester required in Section517.1.6, there shall be no additional devices of any typein any portion of the appliance, flue pipe, and chimney ofa natural draft solid-fuel operation.

517.8.4 No solid-fuel cooking device of any type shallbe permitted for deep-fat frying involving more than one(1) quart of liquid shortening, nor shall any solid-fuelcooking device be permitted within three (3) feet (0.92m) of any deep-fat frying unit.

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EXHAUST SYSTEMS

NEgATIvEPRESSURE

REINF.SPACINg(Inches)

CLASS 1

Up to 7" 8" to 11" 12" to 15" 16" to 19" 20" to 23" 24" to 35" 36" to 47" 48" to 59" 60"

To 7" 0 .021 (24 ga.) .021 (24 ga.) .033 (20 ga.) .044 (18 ga.) .055 (16 ga.) .068 (14 ga.) .127 (10 ga.)

96 .021 (24 ga.) .021 (24 ga.) .021 (24 ga.) .027 (22 ga.) .033 (20 ga.) .044 (18 ga.) .055 (16 ga.) .068 (14 ga.) .068 (14 ga.)



8" to 11" 0 .021 (24 ga.) .027 (22 ga.) .044 (18 ga.) .055 (16 ga.) .068 (14 ga.) .097 (12 ga.)




12" to 15" 0 .021 (24 ga.) .033 (20 ga.) .055 (16 ga.) .068 (14 ga.) .097 (12 ga.) .097 (12 ga.)




16" to 20" 0 .021 (24 ga.) .044 (18 ga.) .068 (14 ga.) .097 (12 ga.) .112 (11 ga.)




To 7" 0

CLASS 2

.027 (22 ga.) .027 (22 ga.) .033 (20 ga.) .044 (18 ga.) .055 (16 ga.) .068 (14 ga.) .127 (10 ga.)




8" to 11" 0 .027 (22 ga.) .027 (22 ga.) .044 (18 ga.) .055 (16 ga.) .068 (14 ga.) .097 (12 ga.)




12" to 15" 0 .027 (22 ga.) .033 (20 ga.) .055 (16 ga.) .068 (14 ga.) .097 (12 ga.) .097 (12 ga.)




16" to 20" 0 .027 (22 ga.) .044 (18 ga.) .068 (14 ga.) .097 (12 ga.) .112 (11 ga.)




To 7" 0

CLASS 3

.033 (20 ga.) .033 (20 ga.) .044 (18 ga.) .044 (18 ga.) .055 (16 ga.) .068 (14 ga.) .127 (10 ga.)




8" to 11" 0 .033 (20 ga.) .033 (20 ga.) .044 (18 ga.) .055 (16 ga.) .068 (14 ga.) .097 (12 ga.)




TABLE 5-5

MINIMUM SHEET METAL THICkNESS FOR ROUND DUCTS FOR PRODUCT-CONvEYINg SYSTEM DUCTS

101

EXHAUST SYSTEMS

NEgATIvEPRESSURE

REINF.SPACINg(Inches)

CLASS 3

Up to 7" 8" to 11" 12" to 15" 16" to 19" 20" to 23" 24" to 35" 36" to 47" 48" to 59" 60"

12" to 15" 0 .033 (20 ga.) .033 (20 ga.) .055 (16 ga.) .068 (14 ga.) .097 (12 ga.) .097 (12 ga.)




16" to 20" 0 .033 (20 ga.) .044 (18 ga.) .068 (14 ga.) .097 (12 ga.) .112 (11 ga.)




To 7" 0

CLASS 4

.055 (16 ga.) .055 (16 ga.) .055 (16 ga.) .055 (16 ga.) .055 (16 ga.) .068 (14 ga.) .068 (14 ga.)




8" to 11" 0 .055 (16 ga.) .055 (16 ga.) .055 (16 ga.) .055 (16 ga.) .068 (14 ga.) .097 (12 ga.)




12" to 15" 0 .055 (16 ga.) .055 (16 ga.) .055 (16 ga.) .068 (14 ga.) .097 (12 ga.) .097 (12 ga.)




16" to 20" 0 .055 (16 ga.) .055 (16 ga.) .068 (14 ga.) .097 (12 ga.) .112 (11 ga.)




TABLE 5-5 (continued)

MINIMUM SHEET METAL THICkNESS FOR ROUND DUCTS FOR PRODUCT-CONvEYINg SYSTEM DUCTS

Note: 1 in. = 25.4 mm

102

EXHAUST SYSTEMS

TABLE 5-6

MINIMUM SHEET METAL THICkNESS FOR RECTANgULAR DUCTS

NEgATIvEPRESSURE

REINF.SPACINg

LONgEST SIDE OF DUCT

CLASS 1 CLASS 2

Up to 12" 13" to 24" 25" to 36" 37" to 48" 49" to 60" Up to 12" 13" to 24" 25" to 36" 37" to 48" 49" to 60"

To 7" 48 .021 (24 ga.) .033 (20 ga.) .055 (16 ga.) .068 (14 ga.) .033 (20 ga.) .044 (18 ga.) .055 (16 ga.) .068 (14 ga.)

To 7" 24 .021 (24 ga.) .027 (22 ga.) .033 (20 ga.) .033 (20 ga.) .033 (20 ga.) .033 (20 ga.) .044 (18 ga.) .055 (16 ga.) .055 (16 ga.) .055 (16 ga.)


8" to 11" 48 .027 (22 ga.) .068 (14 ga.) .097 (12 ga.) .097 (12 ga.) .033 (20 ga.) .068 (14 ga.) .097 (12 ga.) .097 (12 ga.)

8" to 11" 24 .027 (22 ga.) .055 (16 ga.) .055 (16 ga.) .068 (14 ga.) .068 (14 ga.) .033 (20 ga.) .055 (16 ga.) .055 (16 ga.) .068 (14 ga.) .068 (14 ga.)


12" to 15" 48 .044 (18 ga.) .097 (12 ga.) .044 (18 ga.) .044 (18 ga.)



16" to 20" 48 .068 (14 ga.) .112 (11 ga.) .068 (14 ga.) .112 (11 ga.)



To 7" 48

CLASS 3 CLASS 4

.044 (18 ga.) .055 (16 ga.) .068 (14 ga.) .068 (14 ga.) .055 (16 ga.) .068 (14 ga.) .097 (12 ga.) .097 (12 ga.)



8" to 11" 48 .044 (18 ga.) .068 (14 ga.) .097 (12 ga.) .097 (12 ga.) .055 (16 ga.) .068 (14 ga.) .097 (12 ga.) .097 (12 ga.)



12" to 15" 48 .044 (18 ga.) .097 (12 ga.) .055 (16 ga.) .097 (12 ga.)



16" to 20" 48 .068 (14 ga.) .112 (11 ga.) .055 (16 ga.) .112 (11 ga.)



Note: 1 in. = 25.4 mm

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