chapter 5 - iapmo group report on comments/2012 uniform mechanical … · this chapter includes...

501.0 Scope General.

501.1 Applicability. This chapter includes requirements forenvironmental air ducts, product-conveying systems, andcommercial hoods and kitchen ventilation.

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

502.0 Product-Conveying Ducts Classification.

502.1 General. Product-conveying ducts shall be classifiedaccording to their use, 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 graindust, and buffing and polishing dust.

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

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 providethe required air movement. Motors in areas that contain flam-mable vapors or dusts shall be of a type approved for suchenvironments. A manually operated remote control installedat an approved location shall be provided to shut off fans orblowers in flammable vapor or dust systems. Electrical equip-ment used in operations that generate explosive or flammablevapors, fumes, or dusts shall be interlocked with the ventila-tion system so that the equipment cannot be operated unlessthe ventilation fans are in operation. Motors for fans used toconvey flammable vapors or dusts shall be located outsidethe duct or shall be protected with approved shields and dust-proofing. Motors and fans shall be accessible for servicingand 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. Where the size and hardness ofmaterials passing through a fan could produce are capable ofproducing a spark, both the fan and the casing shall be ofnonsparking materials. Where fans are required to be spark-resistant, their bearings shall not be within the airstream, andall parts of the fan shall be grounded. Fans in systemshandling materials that are likely to clog the blades, and fansin buffing or woodworking exhaust systems, shall be of theradial-blade or tube-axial type.

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. Air filters shall be listed units. Liquidadhesive coatings used on filters shall have a flash point of350˚F (177˚C) or higher, as determined in accordance withthe fire code standards.

504.0 Environmental Air Ducts.

504.1 Makeup and Exhaust-Air Ducts. Environmentalair ducts not regulated by other provisions of this code shallbe in accordance with this section. Ducts shall be substan-tially airtight as approved by the Authority Having Jurisdic-tion, and shall comply with the provisions of Chapter 6.Exhaust ducts under positive pressure shall not extend into orthrough ducts or plenums. Exhaust ducts shall terminateoutside the building and shall be equipped with back-draftdampers. Environmental air ducts that have an alternate func-tion as a part of an approved smoke-control system do notrequire design 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 shall bepermitted to be of approved 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 1 inch (25.4 mm) of 6 inch diameter (152mm) PVC coupling shall be permitted to protrude abovethe concrete 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 ExhaustDucts. Moisture exhaust ducts shall terminate on the outside ofthe building and shall be equipped with a back-draft damper.Screens shall not be installed at the duct termination. Ducts forexhausting clothes dryers shall not be connected or installedwith sheet metal screws or other fasteners that will obstruct theflow. Clothes dryer moisture exhaust ducts shall not beconnected to a gas vent connector, gas vent, or chimney, andshall only serve clothes dryers. Clothes dryer moisture exhaustducts under positive pressure shall not extend into or throughducts or plenums.

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44 UNIFORM MECHANICAL CODE

504.3.21 Domestic Clothes Dryers. Where a

compartment or space for a domestic clothes dryer is

provided, not less than a 4 inch diameter (102 mm) mois-

ture exhaust duct of approved material shall be installed in

accordance with this section and Section 504.0.

Where a closet is designed for the installation of a

clothes dryer, an opening of not less than 100 square inches

(64 516 mm2) for makeup air shall be provided in the door

or by other approved means.

504.3.21.1 Domestic Dryer Vents. Domestic

clothes dryer moisture exhaust ducts shall be of metal

and shall have smooth interior surfaces.

Exception: Listed clothes dryer transition ducts not

more than 6 feet (1829 mm) in length shall be

permitted to be used in connection with domestic dryer

exhausts.

Flexible clothes dryer transition ducts shall not be

concealed within construction.

504.3.21.2 Length Limitation. Unless otherwise

permitted or required by the dryer manufacturer’s

installation instructions and approved by the Authority

Having Jurisdiction, domestic dryer moisture exhaust

ducts shall not exceed a total combined horizontal and

vertical length of 14 feet (4267 mm), including two 90

degree (1.57 rad) elbows. A length of 2 feet (610 mm)

shall be deducted for each 90 degree (1.57 rad) elbow

in excess of two.

504.3.32 Commercial Clothes Dryers. Commercial

dryer exhaust ducts shall be installed in accordance with

their listings. The installation of commercial clothes dryer

exhaust ducts shall comply with the appliance manufac-

turer’s installation instructions.

504.4 Heat (Energy) Recovery Ventilators. 504.4.1

Installation. Heat (energy) recovery ventilators shall be

installed in accordance with their listings and comply with the

appliance manufacturer’s installation instructions. Heat (energy)

recovery ventilator ducts shall comply with the provisions of

Chapter 6.

504.5 Termination of Environmental Air Ducts. Envi-

ronmental air duct exhaust shall not terminate less than 3 feet

(914 mm) from a property line and 3 feet (914 mm) from open-

ings into the building.

504.6 Gypsum Wallboard Ducts. Bathroom and laundry

room exhaust ducts shall be permitted to be of gypsum wall-

board subject to the limitations of Section 602.1.

505.0 Design of Product-Conveying Ventilation

Systems.

505.1 General. A mechanical ventilation or exhaust system

shall be installed to control, capture, and remove emissions

generated from product use or handling where required by in

accordance with the building code or fire code and where

such emissions result in a hazard to life or property. The

design of the system shall be such that the emissions are

confined to the area in which they are generated by air

currents, hoods, or enclosures and shall be exhausted by a

duct system to a safe location or treated by removing conta-

minant's. Ducts conveying explosives or flammable vapors,

fumes, or dusts shall extend directly to the exterior of the

building without entering other spaces and shall not extend

into or through ducts and plenums.

Exception: Ducts conveying vapor or fumes having flam-mable constituents less than 25 percent of their Lower Flam-mability Limit (LFL) shall be permitted to pass through otherspaces.

505.1.1 Incompatible Materials. Incompatible mate-rials shall not be conveyed in the same system.

505.1.2 Flammability Limit. In systems conveyingflammable vapors, gases, or mists, the concentrationshall not exceed 25 percent of the lower flammabilitylimit (LFL).

Exception: Higher concentrations shall be permittedwhere the exhaust system is designed and protected inaccordance 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 contaminant's 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-inant's 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 contaminant'sare generated shall be diluted below 25 percent of their lowerexplosive limit or lower flammability limit with air that doesnot contain other contaminant's. The velocity of air within theduct shall be not less than set forth in Table 505.2. Systems forremoval of vapors, gases, and smoke shall be designed by theconstant velocity or equal friction methods.

Systems conveying particulate matter shall be designedemploying the constant velocity method. Systems conveyingexplosive or radioactive materials shall be pre-balanced throughduct sizing. Other systems shall be permitted to be designedwith balancing devices such as dampers. Dampers provided tobalance airflow shall be provided with securely fixedminimum-position blocking devices to prevent restricting flowbelow the required volume or velocity.

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45UNIFORM MECHANICAL CODE

505.3 Makeup Air. Makeup air shall be provided toreplenish air exhausted by the ventilation system. Makeup airintakes shall be located so as to avoid recirculation of contam-inated air within enclosures.

505.4 Hoods and Enclosures. Hoods and enclosuresshall be used where contaminant's originate in a concentratedarea. The design of the hood or enclosure shall be such that aircurrents created by the exhaust systems will capture the cont-aminant's and transport them directly to the exhaust duct. Thevolume of air shall be sufficient to dilute explosive or flam-mable vapors, fumes, or dusts as set forth in accordance withSection 505.2. Hoods of steel shall have a base metal thick-ness not less than 0.027 of an inch (0.69 mm) (No. 22 gauge)for Class 1 and Class 5 metal duct systems; 0.033 of an inch(0.84 mm) (No. 20 gauge) for hoods serving a Class 2 ductsystem; 0.044 of an inch (1.12 mm) (No. 18 gauge) for hoodsserving a Class 3 duct system; and 0.068 of an inch (1.73 mm)(No. 14 gauge) for hoods serving a Class 4 duct system.

Approved nonmetallic hoods and duct systems shall bepermitted to be used for Class 5 corrosive systems where thecorrosive mixture is nonflammable. Metal hoods used withClass 5 duct systems shall be protected with suitable anapproved corrosion-resistant material. Edges of hoods shall berounded. The minimum clearance between hoods andcombustible construction shall be the clearance required by theduct system.

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.

Exceptions:

(1) Asbestos-cement, concrete, clay, or ceramic materials shallbe permitted to be used where it is shown that these mate-rials will be equivalent to metal ducts installed in accor-dance with this chapter.

(2) Ducts serving a Class 5 system shall be permitted to beconstructed of approved nonmetallic material where thecorrosive characteristics of the material being conveyed

make a metal system unsuitable and where the mixturebeing conveyed is nonflammable.

Approved nonmetallic material shall be either a listedproduct having a flame-spread index of not exceeding 25 orless and a smoke-developed rating of 50 or less on bothinside and outside surfaces without evidence of continuedprogressive combustion, or shall have a flame-spread indexof not exceeding 25 or less and shall be installed with anautomatic fire-sprinkler protection system inside the duct.

(3) Ducts used in central vacuum cleaning systems within adwelling unit shall be constructed of materials in compli-ance accordance with the applicable standards referencedin Chapter 17. Penetrations of fire walls or floor-ceiling orroof-ceiling assemblies shall be in accordance with thebuilding code.

Copper or ferrous pipes or conduits extending from withinthe separation between a garage and dwelling unit to the centralvacuuming unit shall be permitted to 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 shall not beused where the temperature of the material being conveyedexceeds 400˚F (2054˚C).

Metal ducts used in Class 5 systems that are not resistant tothe corrosiveness of the product shall be protected with appro-priate an approved corrosion-resistant material.

506.2 Construction. Ducts used for conveying products shallbe of substantial airtight construction as approved by theAuthority Having Jurisdiction, and shall not have openings otherthan those required for operation and maintenance of the system.Ducts constructed of steel shall comply with Table 506.2(a1) orTable 506.2(b2).

Exceptions:

(1) Class 1 product-conveying ducts that operate at less than 4inches (102 mm) water column (995.6 996 Pa) negativepressure and convey noncorrosive, nonflammable, andnonexplosive materials at temperatures not exceeding250˚F (121˚C) shall be permitted to be constructed inaccordance with Table 602.1(a), through Table 602.1(f),and Table 604.2, or SMACNA HVAC Duct ConstructionStandards Metal and Flexible.

(2) Ducts used in central vacuuming systems within a dwellingunit shall be constructed of materials in compliance accor-dance with the applicable standards referenced in Chapter17. Penetrations of fire-resistive walls, or floor-ceiling orroof-ceiling assemblies shall be in accordance with theBbuilding Ccode. Copper or ferrous pipes or conduitextending from within the separation between a garage anddwelling unit to the central vacuum unit shall be permittedto be used.

The use of rectangular ducts conveying particulates shall besubject to approval of the building official. The design of rectan-gular ducts shall consider the adhesiveness and buildup of prod-ucts being conveyed within the duct.

Aluminum construction shall be permitted to be used inClass 1 duct systems only. The thickness of aluminum ductsshall be not less than two Brown and Sharpe gauges thicker thanthe gauges required for steel ducts set forth in Table 506.2(a1)and Table 506.2(b2).

TABLE 505.2MINIMUM CONVEYING VELOCITIES

For SI units: 1 foot per minute = 0.005 m/s* The velocity for aluminum and magnesium powder shall be not less

than 4000 feet per minute (20.3 m/s).

TYPE OF PRODUCTSFEETPER

MINUTE

Vapors, gases, smoke, fumes Any

Fine light dusts, such as cotton, lint, and wood flour

(100 mesh and under)

2000

Dry dusts; powders, such as fine rubber molding

power, soap dust

2500*

Industrial dusts:

Average dusts, such as sawdust, grinding dust, coal dust 3500

Heavy dusts, such as metal turnings, lead dusts 4000

Moist dusts and chips, such as lead dust with chips,

sticky buffing lint, quick-lime dust

4500

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NEGATIVEPRESSURE

(incheswater

column)

REINF.SPACING(inches)

CLASS 1 (inches)

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 0.021 (24 ga.) 0.021 (24 ga.) 0.033 (20 ga.) 0.044 (18 ga.) 0.055 (16 ga.) 0.068 (14 ga.) 0.127 (10 ga.) –– ––

96 0.021 (24 ga.) 0.021 (24 ga.) 0.021 (24 ga.) 0.027 (22 ga.) 0.033 (20 ga.) 0.044 (18 ga.) 0.055 (16 ga.) 0.068 (14 ga.) 0.068 (14 ga.)



8 to 11

0 0.021 (24 ga.) 0.027 (22 ga.) 0.044 (18 ga.) 0.055 (16 ga.) 0.068 (14 ga.) 0.097 (12 ga.) –– –– ––




12 to 15

0 0.021 (24 ga.) 0.033 (20 ga.) 0.055 (16 ga.) 0.068 (14 ga.) 0.097 (12 ga.) 0.097 (12 ga.) –– –– ––




16 to 20

0 0.021 (24 ga.) 0.044 (18 ga.) 0.068 (14 ga.) 0.097 (12 ga.) 0.112 (11 ga.) –– –– –– ––




CLASS 2 (inches)

To 7

0 0.027 (22 ga.) 0.027 (22 ga.) 0.033 (20 ga.) 0.044 (18 ga.) 0.055 (16 ga.) 0.068 (14 ga.) 0.127 (10 ga.) –– ––




8 to 11

0 0.027 (22 ga.) 0.027 (22 ga.) 0.044 (18 ga.) 0.055 (16 ga.) 0.068 (14 ga.) 0.097 (12 ga.) –– –– ––




12 to 15

0 0.027 (22 ga.) 0.033 (20 ga.) 0.055 (16 ga.) 0.068 (14 ga.) 0.097 (12 ga.) 0.097 (12 ga.) –– –– ––




16 to 20

0 0.027 (22 ga.) 0.044 (18 ga.) 0.068 (14 ga.) 0.097 (12 ga.) 0.112 (11 ga.) –– –– –– ––




CLASS 3(inches)

To 7

0 0.033 (20 ga.) 0.033 (20 ga.) 0.044 (18 ga.) 0.044 (18 ga.) 0.055 (16 ga.) 0.068 (14 ga.) 0.127 (10 ga.) –– ––




8 to 11

0 0.033 (20 ga.) 0.033 (20 ga.) 0.044 (18 ga.) 0.055 (16 ga.) 0.068 (14 ga.) 0.097 (12 ga.) –– –– ––




TABLE 506.2(a1)

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

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506.3 Fittings. Fittings in Class 2, 3, and 4 systems shall

be not less than two gauges thicker than the thickness required

for straight runs. Flexible metallic duct shall be permitted to

be used for connecting ductwork to vibrating equipment. Duct

systems subject to wide temperature fluctuations shall be

provided with expansion joints.

Branches shall connect to main ducts at the large end of

transitions at an angle not exceeding 45 degrees (0.79 rad).

Except for ducts used to convey noncorrosive vapors

with no particulate, accessible cleanouts shall be provided at

10 foot (3048 mm) intervals and at changes in direction.

Access openings shall also be provided for access to sprin-

klers and other equipment within the duct that require serv-

icing.

506.4 Explosion Venting. Ducts conveying explosivedusts shall have explosion vents, openings protected by anti-flashback swing valves, or rupture diaphragms. Openings torelieve explosive forces shall be located outside the building.Where relief devices cannot provide sufficient pressure relief,

ductwork shall be designed to withstand an internal pressureof not less than 100 pounds-force per square inch (psi) (689kPa).

Where a room or building contains a dust explosionhazard that is external to protected equipment, as defined in2.2.3.1 of NFPA 654, such areas shall be provided with defla-gration venting to a safe outside location.

506.5 Supports. Spacing of supports for ducts shall notexceed 12 feet (3658 mm) for 8 inch (203 mm) ducts nor 20feet (6096 mm) for larger ducts, unless justified by the design.

506.5.1 Loads. Duct supports shall be designed tocarry the weight of the duct half filled with material.Where sprinkler protection is provided in the duct, thehanger’s design shall include the weight of the duct halffilled with water or with the material being conveyed,whichever has the higher density. Loads shall not beplaced on connecting equipment.

Exception: Where adequate approved drainage isprovided, the weight of the water shall not require consid-eration.


EXHAUST SYSTEMS

TABLE 506.2(a1)(continued)

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

NEGATIVEPRESSURE

(incheswater

column)

REINF.SPACING(Inches)

CLASS 3 (continued)(inches)

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 0.133 (20 ga.) 0.133 (20 ga.) 0.155 (16 ga.) 0.168 (14 ga.) 0.197 (12 ga.) 0.197 (12 ga.) –– –– ––




16 to 20

0 0.133 (20 ga.) 0.144 (18 ga.) 0.168 (14 ga.) 0.197 (12 ga.) 0.112 (11 ga.) –– –– –– ––




CLASS 4(inches)

To 7

0 0.155 (16 ga.) 0.155 (16 ga.) 0.155 (16 ga.) 0.155 (16 ga.) 0.155 (16 ga.) 0.168 (14 ga.) 0.168 (14 ga.) –– ––




8 to 11

0 0.155 (16 ga.) 0.155 (16 ga.) 0.155 (16 ga.) 0.155 (16 ga.) 0.168 (14 ga.) 0.197 (12 ga.) –– –– ––




12 to 15

0 0.155 (16 ga.) 0.155 (16 ga.) 0.155 (16 ga.) 0.168 (14 ga.) 0.197 (12 ga.) 0.197 (12 ga.) –– –– ––




16 to 20

0 0.055 (16 ga.) 0.055 (16 ga.) 0.068 (14 ga.) 0.097 (12 ga.) 0.112 (11 ga.) –– –– –– ––




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

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506.5.2 Corrosion. Hangers and supports exposed to

corrosive atmospheres shall be Type 316 SS or equiva-

lent.

506.5.3 Vibration and Stress. To prevent vibration

and stress on the duct, hangers and supports shall be

securely fastened to the building or structure.

506.5.4 Expansion and Contraction. Hangers and

supports shall be designed to allow for expansion and

contraction. [NFPA 91:4.5.6]

506.6 Fire Protection. Sprinklers or other fire-protection

devices shall be installed within ducts having a cross-sectional

dimension exceeding 10 inches (254 mm) where the duct

conveys flammable vapors or fumes. Sprinklers shall be

installed at 12 foot (3658 mm) intervals in horizontal ducts

and at changes in direction. In vertical runs, sprinklers shall

be installed at the top and at alternate floor levels.

506.7 Duct Clearances. 506.7.1 Minimum Clearance.Ductwork and system components handling combustiblematerial and operating at less than 140ºF (60ºC) shall have aclearance of not less than 18 inches (457 mm) fromcombustible construction or any a combustible material.

Exceptions:

(1) Where the ductwork system is equipped with an approvedautomatic extinguishing system designed for the specifichazard, the clearance shall be permitted to be reduced to6 inches (152 mm) from combustible materials and 1⁄2 ofan inch (12.7 mm) from combustible construction.

(2) Where the combustible material and construction isprotected by the use of materials or products listed forprotection purposes or in accordance with Table 506.7.1.

506.7.1.1 Spacers and Ties. Spacers and ties forprotection materials shall be of noncombustible materialand shall not be used directly behind the duct.


EXHAUST SYSTEMS

TABLE 506.2(b2)

MINIMUM SHEET METAL THICkNESS FOR RECTANGULAR DUCTS

NEGATIVEPRESSURE

(incheswater

column)

REINF.SPACING(inches)

LONGEST SIDE OF DUCT

CLASS 1

(inches)

CLASS 2

(inches)

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 0.021 (24 ga.) 0.033 (20 ga.) 0.055 (16 ga.) 0.068 (14 ga.) –– 0.033 (20 ga.) 0.044 (18 ga.) 0.055 (16 ga.) 0.068 (14 ga.) ––

To 7 24 0.021 (24 ga.) 0.027 (22 ga.) 0.033 (20 ga.) 0.033 (20 ga.) 0.033 (20 ga.) 0.033 (20 ga.) 0.044 (18 ga.) 0.055 (16 ga.) 0.055 (16 ga.) 0.055 (16 ga.)


8 to 11 48 0.027 (22 ga.) 0.068 (14 ga.) 0.097 (12 ga.) 0.097 (12 ga.) –– 0.033 (20 ga.) 0.068 (14 ga.) 0.097 (12 ga.) 0.097 (12 ga.) ––

8 to 11 24 0.027 (22 ga.) 0.055 (16 ga.) 0.055 (16 ga.) 0.068 (14 ga.) 0.068 (14 ga.) 0.033 (20 ga.) 0.055 (16 ga.) 0.055 (16 ga.) 0.068 (14 ga.) 0.068 (14 ga.)


12 to 15 48 0.044 (18 ga.) 0.097 (12 ga.) –– –– –– 0.044 (18 ga.) 0.044 (18 ga.) –– –– ––



16 to 20 48 0.068 (14 ga.) 0.112 (11 ga.) –– –– –– 0.068 (14 ga.) 0.112 (11 ga.) –– –– ––



To 7 48

CLASS 3 (inches)

CLASS 4 (inches)

0.044 (18 ga.) 0.055 (16 ga.) 0.068 (14 ga.) 0.068 (14 ga.) –– 0.055 (16 ga.) 0.068 (14 ga.) 0.097 (12 ga.) 0.097 (12 ga.) ––



8 to 11 48 0.044 (18 ga.) 0.068 (14 ga.) 0.097 (12 ga.) 0.097 (12 ga.) –– 0.055 (16 ga.) 0.068 (14 ga.) 0.097 (12 ga.) 0.097 (12 ga.) ––



12 to 15 48 0.044 (18 ga.) 0.097 (12 ga.) –– –– –– 0.055 (16 ga.) 0.097 (12 ga.) –– –– ––



16 to 20 48 0.068 (14 ga.) 0.112 (11 ga.) –– –– –– 0.055 (16 ga.) 0.112 (11 ga.) –– –– ––



For SI units: 1 inch = 25.4 mm, 1 inch water column = 0.249 kPaPRE-PRIN

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506.7.1.2 Air Circulation. With all clearance reduc-tion systems using a ventilated airspace, air circulationshall be provided as described in Table 506.7.1. Thereshall be not less than 1 inch (25.4 mm) between the wallprotector and combustible walls and ceilings for clear-ance, reduction systems using a ventilated space.

506.7.1.3 Wool Batts Insulation. Mineral wool batts(blanket or board) shall have a density of not less than 8pound-force per cubic feet (lb/ft3) (3.6128 kqg/m3) andhave a melting point of not less than 1500ºF (816ºC).

506.7.1.4 Insulation Board. Insulation board used as apart of a clearance-reduction system shall have a thermalconductivity of 1 British thermal unit inch per square foothour degree Fahrenheit (Btu in./ft.2 hrºF) (0.14 W/m2 hrºC)or less. Insulation board shall be formed of noncom-bustible material.

506.7.1.5 Clearance with Wall Protector/Surface. There shall be not less than 1 inch (25.4 mm)

between the duct and the wall protector. In no case shall

the clearance between the duct and the wall surface be

reduced below that shown in Table 506.7.1.

506.7.26 High Temperature Duct Systems. Duct

systems operating at elevated temperatures above

exceeding 140ºF (60ºC) shall have clearances from

combustible building construction or any combustible

materials of not less than 18 inches (457 mm).

506.7.37 Reduced Clearance. 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 sections.

EXHAUST SYSTEMS

TABLE 506.7.1

REDUCTION 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 SECTION 506.7.26

MINIMUM ALLOWABLE

REDUCTION IN CLEARANCE

(PERCENT)

FORM OF PROTECTIONAS WALL

PROTECTOR

AS CEILING

PROTECTOR

(a) 31⁄2 inches thick masonry wall without ventilated airspace 33 ––

(b) 1⁄2 inch thick noncombustible insulation board over 1 inch glass fiber or mineral wool batts without

ventilated airspace50 33

(c) 0.024 inch (No. 24 gauge) sheet metal over 1 inch glass fiber or mineral wool batts reinforced with

wire, or equivalent, on rear face with not less than a 1 inch air gap66 66

(d) 31⁄2 inches thick masonry wall with not less than a 1 inch air gap 66 ––

(e) 0.024 inch (No. 24 gauge) sheet metal with not less than a 1 inch air gap 66 50

(f) 1⁄2 inch thick noncombustible insulation board with not less than a 1 inch air gap 66 50

(g) 0.024 inch (No. 24 gauge) sheet metal with ventilated airspace over 0.024 inch (No. 24 gauge) sheet

metal with not less than a 1 inch air gap 66 50

(h) 1 inch glass fiber or mineral wool batts sandwiched between two sheets 0.024 inch (No. 24 gauge)

sheet metal with not less than a 1 inch air gap 66 50

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.

FIGURE 506.7.1EXTENT OF PROTECTION REqUIRED TO REDUCE CLEARANCES FROM DUCTS.

For SI units: 1 inch = 25.4 mm

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506.7.37.1 Wall Protector. Air circulation shallbe permitted to be provided by leaving all edges ofthe wall protector open with not less than a 1 inch(25.4 mm) airgap.

506.7.37.2 Single Flat Wall. Where the wallprotector is mounted on a single flat wall away fromcorners, air circulation shall be permitted to beprovided by one of the following:

(1) Leaving top and bottom edges open to circulationby maintaining the 1 inch (25.4 mm) airgap.

(2) Leaving top and both side edges open to circula-tion by maintaining the 1 inch (25.4 mm) air gap.

506.7.37.3 Wall Protectors that Cover TwoWalls. Wall protectors that cover two walls in acorner shall be permitted to be open at the top andbottom edges with not less than 1 inch (25.4 mm)air gap. [NFPA 91:4.6.3.3]

506.8 Protection from Physical Damage. Ductsinstalled in locations where they are subject to physicaldamage shall be protected by guards.

506.9 Exhaust Outlets. The termination point for exhaustducts discharging to the atmosphere shall be not less than thefollowing:

(1) Ducts conveying explosive or flammable vapors, fumes,or dusts: 30 feet (9144 mm) from property line; 10 feet(3048 mm) from openings into the building, 6 feet (1829mm) from exterior walls or roofs; 30 feet (9144 mm)from combustible walls or openings into the building thatare in the direction of the exhaust discharge; 10 feet(3048 mm) above adjoining grade.

(2) Other product-conveying outlets: 10 feet (3048 mm)from property line; 3 feet (914 mm) from exterior wall orroof; 10 feet (3048 mm) from openings into the building;10 feet (3048 mm) above adjoining grade.

Part II - Commercial Hoods and kitchen

Ventilation.

507.0 General Requirements.

507.1 Exhaust System. Cooking equipment used inprocesses producing smoke or grease-laden vapors shall beequipped with an exhaust system that complies in accordancewith all the equipment and performance requirements of thischapter, and all such equipment and performance shall be main-tained per this chapter during all periods of operation of thecooking equipment. Specifically, the following equipment shallbe kept in good working condition: [NFPA 96:4.1.1, 4.1.2,4.1.3]:

(1) Cooking equipment

(2) Hoods

(3) Ducts (where applicable)

(4) Fans

(5) Fire suppression systems

(6) Special effluent or energy control equipment

Airflows shall be maintained. Maintenance and repairsshall be performed on all components at intervals necessary tomaintain these conditions [NFPA 96:4.1.3.1, 4.1.4]:

(1) The responsibility for inspection, maintenance, andcleanliness of the ventilation control and fire protectionof the commercial cooking operations shall be the ulti-mate responsibility of the owner of the system providedthat this responsibility has not been transferred in writtenform to a management company or other party. [NFPA96:4.1.5]

(2) Solid-fuel cooking equipment shall be in accordancecomply with the requirements of Section 517.0. [NFPA96:4.1.6]

(3) Multiple-tenancy applications shall require the concertedcooperation of design, installation, operation, and main-tenance responsibilities by tenants and by the buildingowner. [NFPA 96:4.1.7]

(4) Interior surfaces of the exhaust system shall be accessiblefor cleaning and inspection purposes. [NFPA 96:4.1.8]

(5) Cooking equipment used in fixed, mobile, or temporaryconcessions, such as trucks, buses, trailers, pavilions,tents, or any a form of roofed enclosure, shall be in accor-dance with this standard unless all or part of the installa-tion is exempted by the Authority Having Jurisdiction.[NFPA 96:4.1.9]

507.2 Clearance. 507.2.1 Without Enclosures. Whereenclosures are not required, hoods, grease removal devices,exhaust fans, and ducts shall have a clearance of not less than18 inches (457 mm) to combustible material, 3 inches (76mm) to limited-combustible material, and 0 inches (0 mm) tononcombustible material. [NFPA 96:4.2.1]

507.2.21 Listed. Where a hood, duct, or grease removaldevice is listed for clearances less than those required inaccordance with Section 507.2.1, the listing requirementsshall be permitted. [NFPA 96:4.2.2]

507.2.32 Clearance Reduction. 507.2.3.1Noncombustible Spaces. Where a clearance reduc-tion system consisting of 0.013 of an inch (0.33 mm) (28gauge) sheet metal spaced out 1 inch (25.4 mm) onnoncombustible spacers is provided, there shall be notless than 9 inches (229 mm) clearance to combustiblematerial. [NFPA 96:4.2.3.1]

507.2.3.2.1 Mineral Wool Batts or CeramicFiber Blanket. Where a clearance reductionsystem consisting of 0.027 of an inch (0.69 mm) (22gauge) sheet metal on 1 inch (25.4 mm) mineralwool batts or ceramic fiber blanket reinforced withwire mesh or equivalent spaced out 1 inch (25.4mm) on non-combustible spacers is provided, thereshall be not less than 3 inches (76 mm) clearance tocombustible material. [NFPA 96:4.2.3.2]

507.2.3.32.2 Zero Clearance. Zero clearance tolimited-combustible materials shall be permittedwhere protected by metal lath and plaster, ceramic tile,quarry tile, other non-combustible materials orassembly of noncombustible materials, or materialsand products that are listed for the purpose of reducingclearance. [NFPA 96:4.2.3.3]


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507.2.43 Clearance Integrity. 507.2.4.1 Damage. Inthe event of damage, the material or product shall berepaired and restored to meet its intended listing or clear-ance requirements and shall be acceptable to approved bythe aAuthority hHaving jJurisdiction. [NFPA 96:4.2.4.1]

507.2.43.21 Fire. In the event of a fire within akitchen exhaust system, the duct and its enclosure(rated shaft, factory-built grease duct enclosure, orfield-applied grease duct enclosure) shall be inspectedby qualified personnel to determine whether the ductand protection method are structurally sound, capableof maintaining their fire protection function, and inaccordance with this standard for continued operation.[NFPA 96:4.2.4.2]

507.2.43.32 Required Protection. Protectionshall be provided on the wall from the bottom of thehood to the floor, or to the top of the noncombustiblematerial extending to the floor, to the same level asrequired in Section 507.2.1. [NFPA 96:4.2.4.3]

507.2.43.43 Protection Methods. The protectionmethods for ducts to reduce clearance shall be appliedto the combustible or limited-combustible construc-tion, not to the duct itself. [NFPA 96:4.2.4.4]

507.2.54 Factory Built. Factory-built grease duct enclo-sures shall be protected with a through-penetration firestopsystem classified in accordance with ASTM E 814 or UL1479 having an "F" and "T" rating equal to the fire resist-ance rating of the assembly being penetrated from the pointat which the duct penetrates a ceiling, wall, or floor to theoutlet terminal. The factory-built grease duct protectionsystem shall be listed in accordance with UL 2221. Thefactory-built grease duct protection system shall beinstalled in accordance with the manufacturer's installationinstructions and the listing requirements. [NFPA 96:4.3.3,4.3.3.1, 4.3.3.2]

507.2.65 Field Applied. Field-applied grease duct enclo-sures shall be protected with a through penetration firestopsystem classified in accordance with ASTM E 814 or UL1479 having an “F” and “T” rating equal to the fire resist-ance rating of the assembly being penetrated. The surfaceof the field fabricated grease duct shall be continuouslycovered on all sides from the point at which the duct enclo-sure penetrates a ceiling, wall, or floor to the outletterminal. The field-applied grease duct shall be listed inaccordance with ASTM E 2336 and installed in accordancewith the manufacturer’s installation instructions and thelisting requirements. [NFPA 96:4.3.1, 4.3.1.1, 4.3.1.2]

507.2.76 Both Field-Applied and Factory Built.Field-applied grease duct enclosures and factory-builtgrease duct enclosures shall demonstrate that they providemechanical and structural integrity, resiliency, and stabilitywhere subjected to expected building environmental condi-tions, duct movement under general operating conditions,and duct movement due to fire conditions. [NFPA 96:4.3.4]

507.2.76.1 Physical Damage. Measures shall betaken to prevent physical damage to any a material orproduct used for the purpose of reducing clearances.

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

507.2.76.2 Specification. The specifications ofmaterial, gauge, and construction of the duct used inthe testing and listing of field-applied grease ductenclosures and factory-built grease duct enclosuresshall be included as minimum requirements in theirlisting and installation documentation. [NFPA96:4.3.5]

507.2.76.3 Clearance Options. The followingclearance options for which field-applied grease ductenclosures and factory-built grease duct enclosureshave been successfully evaluated shall be clearly iden-tified in their listing and installation documentationand on their label: [NFPA 96:4.3.6]:

(1) Open combustible construction clearance atmanufacturer’s requested dimensions. [NFPA96:4.3.6(1)]

(2) Closed combustible construction clearance atmanufacturer’s requested dimensions, with orwithout specified ventilation. [NFPA 96:4.3.6(2)]

(3) Rated shaft clearance at manufacturer’s requesteddimensions, with or without specified ventilation.[NFPA 96:4.3.6(3)]

507.2.87 Noncombustible Materials. A duct shall bepermitted to contact noncombustible floors, interior walls,and other noncombustible structures or supports, but it shallnot be not in contact for more than 50 percent of its surfacearea for each linear foot of contact length. [NFPA 96:4.4.1]

507.2.87.1 Corrosion Protection. Where ductcontact must exceed the requirements of Section507.2.87, the duct shall be protected from corrosion.[NFPA 96:4.4.2]

507.2.87.2 Zero Clearance. Where the duct islisted for zero clearance to combustibles or otherwiseprotected with a material or product listed for thepurpose of reducing clearance to zero, the duct shallbe permitted to exceed the contact limits of Section507.2.87 without additional corrosion protection.[NFPA 96:4.4.3]

507.2.98 Clearance Between Duct and InteriorSurfaces. Clearances between the duct and interiorsurfaces of enclosures shall be in accordance with therequirements of Section 507.2. [NFPA 96:4.5]

507.3 Drawings. A drawing(s) of the exhaust system instal-lation along with a copy of operating instructions for subassem-blies and components used in the exhaust system, includingelectrical schematics, shall be available on the premises. [NFPA96:4.6]

507.4 Notification of Any Change. Where required by theAuthority Having Jurisdiction, notification in writing shall begiven of any an alteration, replacement, or relocation of any anexhaust, or extinguishing system or part thereof or cookingequipment. [NFPA 96:4.7] Satisfaction shall be provided to theAuthority Having Jurisdiction that the complete exhaust system

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as addressed in this standard is installed and operable in accor-dance with the approved design and the manufacturer’s instal-lation 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 a food-processing establishment. For the purpose of this section, afood-processing establishment shall include any a building orportion thereof used for the processing of food, but shall notinclude a dwelling unit.

Exceptions:

(1) Cooking appliance that has been listed in accordance withEPA 202 for reduced emissions where the grease dischargedoes not exceed 5.8 ounces per cubic inch (oz/in3) (5mg/m3) where operated with a total airflow of 500 cubicfeet per minute (cfm) (0.236 m3/s).

(2) Recirculating systems listed in accordance with UL 710Band installed in accordance with Section 516.0.

508.1.1 Construction. The hood or that portion of aprimary collection means designed for collecting cookingvapors and residues shall be constructed of and besupported by steel not less than 0.043 of an inch (1.09 mm)(No. 18 MSG) in thickness, stainless steel not less than0.037 of an inch (0.94 mm) (No. 20 MSG) in thickness, orother approved material of equivalent strength and fire andcorrosion resistance. [NFPA 96:5.1.1]

Exceptions:

(1) Listed exhaust hoods with or without exhaustdampers.

(2) Type II hoods shall be constructed of not less than0.024 of an inch (0.61 mm) (No. 24 gauge steel.Hoods constructed of copper shall be of copper sheetsweighing not less than 24 ounces per square foot 0.17oz/in2 (7.32 kg/m2). Joints and seams shall be substan-tially tight. Solder shall not be used except for sealinga joint or seam.

Hoods shall be secured in place by noncom-bustible supports.

508.1.2 Grease Vapor. Wall mounted exhaust hoodassemblies shall be tight fitting against the back wall as tonot permit passage of grease vapor behind the hood, orbetween the back wall and the hood assembly. [NFPA96:5.1.13]

508.2 Seams, Joints and Penetrations. Seams, joints, andpenetrations of the hood enclosure that direct and capturegrease-laden vapors and exhaust gases shall have a liquid-tightcontinuous external weld to the hood’s lower outermostperimeter. [NFPA 96:5.1.2]

508.2.1 Internal Welding. Seams, joints, and penetra-tions of the hood shall be permitted to be internally welded,provided that the weld is formed smooth or ground smooth,so as to not trap grease, and is cleanable. [NFPA 96:5.1.3]

508.2.2 Sealed. Internal hood joints, seams, filtersupport frames, and appurtenances attached inside thehood shall be sealed or otherwise made grease-tight.[NFPA 96:5.1.4]

508.2.3 Listed Sealant. Penetrations shall bepermitted to be sealed by devices that are listed for suchuse and whose presence does not detract from the hood’sor duct’s structural integrity. [NFPA 96:5.1.5]

508.2.4 Construction of Listed Exhaust Hoods.Listed exhaust hoods with or without exhaust dampersshall be permitted to be constructed of materials requiredby the listing. [NFPA 96:5.1.6]

508.2.5 Asssembly of Listed Exhaust Hoods.Listed exhaust hoods with or without exhaust dampersshall be permitted to be assembled in accordance withthe listing requirements. [NFPA 96:5.1.7]

508.2.6 Duct Construction. Eyebrow-type hoodsover gas or electric ovens shall be permitted to have aduct constructed as required in Section 510.0 from theoven flue(s) connected to the hood canopy upstream ofthe exhaust plenum as shown in Figure 508.2.6. [NFPA96:5.1.8.1]

508.2.7 Duct Connection. The duct connecting theoven flue(s) to the hood canopy shall be connected with acontinuous weld or have a duct-to-duct connection. [SeeFigure 511.1.2.1(a1) through and Figure 511.1.2.1(b2)][NFPA 96:5.1.8.2]

508.2.8 Insulation Flame Spread Rating. Insulationmaterials other than electrical insulation shall have a flame

FIGURE 508.2.6TYPICAL SECTION OF EYEBROW-TYPE HOOD.

[NFPA 96:5.1.8.1]

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spread rating of 25 or less where tested in accordance withUL 723. [NFPA 96:5.1.9]

508.2.9 Adhesives or Cements.Adhesives or cementsused in the installation of insulating materials shall be inaccordance with the requirements of Section 508.2.8,where tested with the specific insulating material. [NFPA96:5.1.10]

508.2.10 Listed Devices. Penetrations shall be sealedwith listed devices in accordance with the requirements ofSection 508.2.11. [NFPA 96:5.1.11]

508.2.11 Hood Penetration. Devices that require pene-tration of the hood, such as pipe and conduit penetrationfittings and fasteners, shall be listed in accordance with UL1978. [NFPA 96:5.1.12]

508.3 Insulation. Insulation materials other than electricalinsulation shall have a flame-spread rating of 25 or less wheretested in accordance with UL 723. Adhesives or cements usedin the installation of insulating materials shall be in accordancewith the preceding requirements where tested with the specificinsulating material. [NFPA 96:5.1.9, 5.1.10]

508.4 Hood Size. Hoods shall be sized according to in accor-dance with the following calculations and configured to providefor the capture and removal of grease-laden vapors. (SeeSection 511.2.32)

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 than 6inches (152 mm) beyond the edge of the cooking surface onall open sides, and the vertical distance between the lip ofthe hood and the cooking surface shall not exceed 4 feet(1219 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 with a quantity of air not less than determinedby the application of the following formulas:

Where:

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

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

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

Q = quantity of air, in cubic feet per minute (L/s m3/s).

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

508.4.1.2 Solid-Fuel Cooking Equipment. Theairflow for solid-fuel cooking equipment, grease-

burning charbroilers, and undefined equipment shallbe not less than the following:

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 High Temperature Appliances. TypeI hoods where the cooking equipment includes high-temperature appliances such as deep-fat fryers:



3 or less Q = 100A


508.4.1.4 Medium Temperature Appliances.Type I hoods where the cooking equipment includesmedium-temperature appliances such as rotisseries,grills, and ranges:



3 or less Q = 75A


508.4.1.5 Medium to Low Temperature Appli-ances. 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 additionto all 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 0.46 Lm3/s/m) ofcooking equipment. Listed noncanopy exhaust hoods andfilters shall be sized and installed in accordance with theterms of their listing and the manufacturer’s installationinstructions.

Exception: Listed hood assemblies designed and installedspecifically for the intended use.

508.5 Exhaust Hood Assemblies with IntegratedSupply-Air Plenums. 508.5.1 Construction and Size.The construction and size of exhaust hood assemblies withintegrated supply air plenums shall be in accordance with therequirements of Section 508.1 and Section 508.4. [NFPA96:5.3.1]

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508.5.21 Outer Shell. The construction of the outer

shell or the inner exhaust shell shall be in accordance

with Section 508.1. [NFPA 96:5.3.2]

508.5.32 Inner Shell. Where the outer shell is welded,

the inner shell shall be of grease-tight construction.

[NFPA 96:5.3.3]

508.5.43 Fire Dampers. 508.5.4.1 Location. A fire-

actuated damper shall be installed in the supply air

plenum at each point where a supply air duct inlet or a

supply air outlet penetrates the continuously welded shell

of the assembly. [NFPA 96:5.3.4.1]

508.5.43.21 Listing. The fire damper shall be

listed for such use or be part of a listed exhaust hood

with or without exhaust damper. [NFPA 96:5.3.4.2]

508.5.43.32 Actuating Temperature. The actu-

ation device shall have a maximum temperature

rating of not to exceed 141°C (286°F) 286°F

(141°C). [NFPA 96:5.3.4.3]

508.5.54 Exemption. Supply air plenums that

discharge air from the face rather than from the bottom

or into the exhaust hood and that are isolated from the

exhaust hood by the continuously welded shell extending

to the lower outermost perimeter of the entire hood

assembly shall not require a fire-actuated damper. [NFPA

96:5.3.4.4]

508.6 Listed Hood Assemblies. Listed hood assemblies

shall be installed in accordance with the terms of their listing

and the manufacturer’s installation instructions. [NFPA

96:5.4.1] Listed hood assemblies shall be tested in accordance

with UL 710. [NFPA 96:5.4.2 5.4.1 - 5.4.2]

508.7 Solid-Fuel Hood Assemblies. Where solid-fuel

cooking equipment is to be used, the solid-fuel hood assembly

shall be in accordance with Section 517.0.

508.8 Listed Ultra-Violet Hoods. Listed ultra-violet

hoods shall be installed and maintained in accordance with

the terms of their listing and the manufacturer’s instructions.

[NFPA 96:5.5]

508.9 Exhaust Outlets. An exhaust outlet within an

unlisted hood shall be located so as to optimize the capture of

particulate matter. Each outlet shall serve not more than a 12

foot (3658 mm) section of an unlisted hood.

509.0 Grease Removal Devices in Hoods.

509.1 Grease Removal Devices. Listed grease filters,

baffles, or other approved grease removal devices for use with

commercial cooking equipment shall be provided. Listed

grease filters shall be tested in accordance with UL 1046.

Mesh filters shall not be used. [NFPA 96:6.1.1-6.1.3]

509.2 Installation. 509.2.1 Distance. The distance between

the grease removal device and the cooking surface shall be as

great as possible but not less than 18 inches (457 mm). [NFPA

96:6.2.1.1]

509.2.21 Vertical Distance. Where grease removal

devices are used in conjunction with charcoal or char-

coal-type broilers, including gas or electrically heated

charbroilers, a vertical distance of not less than 4 feet

(1219 mm) shall be maintained between the lower edge

of the grease removal device and the cooking surface.

[NFPA 96:6.2.1.2]

Exceptions:

(1) Grease removal devices supplied as part of listed

hood assemblies shall be installed in accordance

with the terms of the listing and the manufacturer’s

installation instructions. [NFPA 96:6.2.1.5]

(2) For cooking equipment without exposed flame and

where flue gases bypass grease removal devices, the

minimum vertical distance shall be permitted to be

reduced to not less than 6 inches (152 mm). [NFPA

96:6.2.1.3]

(3) Where a grease removal device is listed for separa-

tion distances less than those required in Section

509.2.1 and Section 509.2.21, the listing require-

ments shall be permitted. [NFPA 96:6.2.1.4]

509.2.32 Grease Removal Device Protection.Grease removal devices shall be protected from combus-

tion gas outlets and from direct flame impingement occur-

ring during normal operation of cooking appliances

producing high flue gas temperatures, where the distance

between the grease removal device and the appliance flue

outlet (heat source) is less than 18 inches (457 mm). [NFPA

96:6.2.2.1]

509.2.32.1 Installation. This protection shall be

permitted to be accomplished by the installation of a

steel or stainless steel baffle plate between the heat

source and the grease removal device. [NFPA

96:6.2.2.2]

509.2.32.2 Size and Location. The baffle plate

shall be sized and located so that flames or combustion

gases shall travel a distance not less than 18 inches

(457 mm) from the heat source to the grease removal

device. [NFPA 96:6.2.2.3]

509.2.32.3 Clearance. The baffle shall be located

not less than 6 inches (152 mm) from the grease

removal devices. [NFPA 96:6.2.2.4]

509.2.43 Grease Filters. Grease filters shall be listed

and constructed of steel or listed equivalent material and

shall be of rigid construction that will not distort or crush

under normal operation, handling, and cleaning conditions.

[NFPA 96:6.2.3.1 and - 6.2.3.2]

509.2.43.1 Arrangement. Filters shall be tight

fitting and firmly held in place and grease filters shall

be arranged so that all exhaust air passes through the

grease filters. [NFPA 96-04:6.2.3.3]

509.2.43.2 Accessibility. Filters shall be easily

accessible and removable for cleaning. [NFPA

96:6.2.3.4]

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509.2.43.3 Angled Installation. Filters shall beinstalled at an angle not less than 45 degrees (0.79rad) from the horizontal. [NFPA 96:6.2.3.5]

509.2.54 Grease Drip Trays. Filters shall be equippedwith a drip tray beneath their lower edges. [NFPA96:6.2.4.1]

509.2.54.1 Size and Pitch. The tray shall be keptto the minimum size needed to collect grease andshall be pitched to drain into an enclosed metalcontainer having a capacity not exceeding 1 gallon(3.785 L) [NFPA 96:6.2.4.2, and 6.2.4.3].

509.2.65 Grease Filter Orientation. Grease filtersthat require 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. Wheresolid-fuel cooking equipment is provided with grease removaldevices, these devices shall be in accordance with Section517.0.

510.0 Exhaust Duct Systems.

510.1 General. 510.1.1 Fire Walls/Partitions. Ductsshall not pass through fire walls or fire partitions. [NFPA96:7.1.1]

510.1.21 Fire Hazards. Ducts shall lead as directly asis practicable to the exterior of the building, so as not tounduly increase any a fire hazard. [NFPA 96:7.1.2]

510.1.32 Interconnection. Duct systems shall not beinterconnected with any other a building ventilation orexhaust system. [NFPA 96:7.1.3]

510.1.43 Duct Installation. Ducts shall be installedwithout forming dips or traps that might collect residues.[NFPA 96:7.1.2] In manifold (common duct) systems, thelowest end of the main duct shall be connected flush onthe bottom with the branch duct. [NFPA 96:7.1.34.1] Ductsystems serving a Type I hood shall be so constructed andinstalled that grease cannot become pocketed in any aportion thereof, and the system shall slope not less than 1⁄4inch per lineal foot (21 20.8 mm/m) toward the hood ortoward an approved grease reservoir. Where horizontalducts exceed 75 feet (22 860 mm) in length, the slopeshall be not less than 1 inch per lineal foot (83 mm/m).

510.1.54 Accessibility. Openings required for acces-sibility shall be in accordance with Section 510.3. [NFPA96:7.1.5]

510.1.65 Sign. A sign shall be placed on all accesspanels stating the following [NFPA 96:7.1.6]:

ACCESS PANEL––DO NOT OBSTRUCT

510.1.76 Bracing and Supports. Duct bracing andsupports shall be of noncombustible material, securelyattached to the structure and designed to carry gravity andlateral loads within the stress limitations of the buildingcode. Bolts, screws, rivets, and other mechanical fastenersshall not penetrate duct walls.

510.1.87 Ducts, Non-Grease. Ducts and plenums

serving Type II hoods shall be constructed of rigid

metallic materials as set forth in accordance with Chapter

6. Duct bracing and supports shall comply with Chapter

6. Ducts subject to positive pressure shall be adequately

sealed.

510.2 Clearance. 510.2.1 Required. Clearance betweenducts and combustible materials shall be provided in accor-dance with the requirements of Section 507.2. [NFPA 96:7.2]

510.2.21 Installation. Listed grease ducts shall beinstalled in accordance with the terms of their listingsand manufacturer’s installation instructions.

510.3 Openings. 510.3.1 Location. Openings shall beprovided at the sides or at the top of the duct, whichever ismore accessible, and at changes of direction. Openings shallbe protected by approved access panels that are in accordancewith Section 510.3.43.4.

Exception: Openings shall not be required in portions of theduct that are accessible from the duct entry or discharge. [NFPA96:7.3.3]

510.3.21 Access Panel. For hoods with dampers inthe exhaust or supply collar, an access panel for cleaningand inspection shall be provided in the duct or the hoodcollar. This access panel shall be as close to the hood aspossible but shall not exceed 18 inches (457 mm).

Exception: Dampers that are accessible from under thehood.

510.3.32 Access for Cleaning and Inspection.Exhaust fans with ductwork connected to both sides shallhave access for cleaning and inspection within 3 feet (914mm) of each side of the fan. [NFPA 96:7.3.7]

510.3.43 Openings in Ducts. Openings shall beprovided in accordance with the requirements of Section510.3.43.1 through Section 510.3.43.5. [NFPA 96:7.4]

510.3.43.1 Horizontal Ducts. On horizontal ducts,not less than one 20 inch by 20 inch (508 mm by 508mm) opening shall be provided for personnel entry.[NFPA 96:7.4.1.1]

510.3.43.1.1(A) Cleaning. Where an openingof this size is not possible, openings large enoughto permit thorough cleaning shall be provided at12 feet (3658 mm) intervals. [NFPA 96:7.4.1.2]

510.3.43.1.2(B) Safe Access and WorkPlatform. Openings on horizontal grease ductsystems shall be provided with safe access and awork platform where not easily accessible from a10 feet (3048 mm) stepladder. [NFPA 96:7.4.1.3]

510.3.43.1.3(C) Support. Support systemsfor horizontal grease duct systems 24 inches(6109 mm) and larger in a cross-sectionaldimension shall be designed for the weight ofthe ductwork plus 800 pounds (363 kg) at any apoint in the duct systems. [NFPA 96:7.4.1.4]

510.3.43.2 Nonlisted Ductwork. On nonlistedductwork, the edge of the opening shall be not lessthan 11⁄2 inches (38 mm) from all outside edges ofthe duct or welded seams. [NFPA 96:7.4.1.5]

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510.3.43.3 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]

510.3.43.3.1(A) Access. Where personnelentry is not possible, an access for cleaningshall be provided on each floor. [NFPA96:7.4.2.2]

510.3.43.4 Access Panels. Access panels shallbe of the same material and thickness as the duct(Section 510.5.1). Access panels shall have a gasketor sealant that is rated for 1500°F (815.6°C) andshall be grease-tight. Fasteners, such as bolts, weldstuds, latches, or wing nuts, used to secure the accesspanels shall be carbon steel or stainless steel andshall not penetrate duct walls. [NFPA 96:7.4.3.1 -7.4.3.3]

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 installation instructions. [NFPA 96:7.4.3.4]

510.3.43.5 Fire Protection System Devices.Openings for installation, servicing, and inspectionof listed fire protection system devices and for ductcleaning shall be provided in ducts and enclosuresand shall be in accordance with the requirements ofSection 510.3 and Section 510.7.4. Enclosure open-ings required to reach access panels in the ductworkshall be large enough for the removal of the accesspanel. [NFPA 96: 7.4.4.1, 7.4.4.2]

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

510.5 Other Grease Ducts. Other grease ducts shall be inaccordance comply with the requirements of this section.[NFPA 96:7.5]

510.5.1 Materials. Ducts shall be constructed of andsupported by carbon steel not less than 0.054 of an inch(1.37 mm) (No. 16 MSG) in thickness or stainless steelnot less than 0.043 of an inch (1.09 mm) (No. 18 MSG)in thickness. [NFPA 96:7.5.1.1]

510.5.2 Installation. 510.5.2.1 Liquid Tight.Seams, joints, penetrations, and duct-to-hood collarconnections shall have a liquid-tight continuous externalweld. [NFPA 96:7.5.2.1]

Exceptions:

(1) Duct-to-hood collar connections as shown in Figure510.5.2.1 shall not require a liquid-tight continuousexternal weld. [NFPA 96:7.5.2.2].

(2) Penetrations shall be permitted to be sealed by otherlisted devices that are tested to be grease-tight and areevaluated under the same conditions of fire severity asthe hood or enclosure of listed grease extractors andwhose presence does not detract from the hood's orduct's structural integrity. [NFPA 96:7.5.2.3]

(3) Internal welding shall be permitted, provided the jointis formed or ground smooth and is readily accessiblefor inspection. [NFPA 96:7.5.2.4]

510.5.2.21 Welded Duct Connection. Duct-to-duct connection shall be as follows: [NFPA96:7.5.5.1]

(1) Telescoping joint, as shown in Figure510.5.2.21(a1).

(2) Bell type joint, as shown in Figure510.5.2.21(b2).

(3) Flange with edge weld, as shown in Figure510.5.2.21(c3).

(4) Flange with filled weld, as shown in Figure510.5.2.21(d4).

510.5.2.32 Butt Welded Connections. Buttwelded connections shall not be permitted. [NFPA96:7.5.5.2]

510.5.2.43 Inside Duct Section. For telescopingand bell-type connections, the inside duct sectionshall be uphill of the outside duct section. [NFPA96:7.5.5.3]

510.6 Exterior Installations. 510.6.1 Supports. Theexterior portion of the ductwork shall be vertical whereverpossible and shall be installed and adequately supported onthe exterior of a building. Bolts, screws, rivets, and othermechanical fasteners shall not penetrate duct walls. Clearanceof any a ducts shall be in accordance with Section 507.2.[NFPA 96:7.6.1 - 7.6.3]

EXHAUST SYSTEMS

FIGURE 510.5.2.1PERMITTED DUCT-TO HOOD COLLAR CONNECTION

[NFPA 96:7.5.2.2]

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510.6.21 Weather Protection. Ducts shall be protectedon the exterior by paint or other suitable weather-protec-tive coating or shall be constructed of noncorrosive stain-less steel. Ductwork subject to corrosion shall haveminimal contact with the building surface.

510.7 Interior Installations. 510.7.1 Enclosure. In all

buildings more than one story in height, and in one-story build-

ings where the roof-ceiling assembly is required to have a fire

resistance rating, the ducts shall be enclosed in a continuous

enclosure extending from the lowest fire-rated ceiling or floor

above the hood, through any concealed spaces, to or through

the roof so as to maintain the integrity of the fire separations

required by the applicable Bbuilding Ccode provisions. The

enclosure shall be sealed around the duct at the point of pene-

tration of the lowest fire-rated ceiling or floor above the hood in

order to maintain the fire resistance rating of the enclosure and

shall be vented to the exterior of the building through weather-

protected openings. [NFPA 96:7.7.1.2 - 7.7.1.4]

Exception: The continuous enclosure provisions shall not be

required where a field-applied grease duct enclosure or a

factory-built grease duct enclosure (See Section 507.2.32) is

protected with a listed duct-through-penetration protection

system equivalent to the fire resistance rating of the assembly

being penetrated, and the materials are installed in accordance

with the conditions of their listings and the manufacturer’s’

installation instructions and are acceptable to the Authority

Having Jurisdiction. [NFPA 96:7.7.1.5]

EXHAUST SYSTEMS

FIGURE 510.5.2.21(d4)

FLANGE WITH FILLED WELD DUCT CONNECTION

[NFPA 96: FIGURE 7.5.5.1(d)]


Notes:

1. Duct size decreases (going upward) with each telescope.

2. Smaller (inside) duct is always above or uphill (on sloped duct), to be

self draining into larger (outside) duct.

FIGURE 510.5.2.21(a1)TELESCOPING -TYPE DUCT CONNECTION

[NFPA 96:7.5.5.1(a)]

FIGURE 510.5.2.21(b2)BELL-TYPE DUCT CONNECTION

[NFPA 96:7.5.5(b)]


Notes:

1. Duct size stays the same throughout the duct system.

2. Smaller (inside) male duct end is always above or uphill (on sloped

duct), to be self-draining into larger (outside) female duct end.

FIGURE 510.5.2.21(c3)

FLANGE WITH EDGE WELD DUCT CONNECTION

[NFPA 96: FIGURE 7.5.5.1(c)]

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510.7.21 Minimum Requirements. The enclosure

required in Section 510.7.1 shall be provided in accor-

dance with Section 510.7.21.1 through Section 510.7.21.3.

510.7.21.1 Less than Four Stories. Where the

building is less than four stories in height, the enclo-

sure wall shall have a fire resistance rating of not

less than 1 hour. [NFPA 96: 7.7.2.1.1]

510.7.21.2 Four Stories or More. Where the

building is four stories or more in height, the enclo-

sure wall shall have a fire resistance rating of not

less than 2 hours. [NFPA 96: 7.7.2.1.2]

510.7.21.3 Clearance. Clearance from the duct or

the exhaust fan to the interior surface of enclosures

of combustible construction shall be not less than 18

inches (457 mm), and clearance from the duct to the

interior surface of enclosures of noncombustible or

limited-combustible construction shall be not less

than 6 inches (152 mm). Provisions for reducing

clearances as described in Section 507.2 are not appli-

cable to enclosures. [NFPA 96: 7.7.2.2.1 - 7.7.2.2.3]

Exception: Clearance from the outer surfaces of

field-applied grease duct enclosures and factory-

built grease duct enclosures to the interior surfaces

of construction installed around them shall be

permitted to be reduced where the field-applied

grease duct enclosure materials and the factory-built

grease duct enclosures are installed in accordance

with the conditions of their listings and the manu-

facturer’s’ installation instructions and are accept-

able to the Authority Having Jurisdiction. [NFPA 96:

7.7.2.2.4]

510.7.32 Materials. For field-applied grease duct enclo-

sures and factory-built grease duct enclosures, the mate-

rials and products shall be provided in accordance with to

Section 510.7.32.1 through Section 510.7.32.3.

510.7.32.1 Mechanical and StructuralIntegrity. Field-applied grease duct enclosures and

factory-built grease duct enclosures shall provide

mechanical and structural integrity, resiliency, and

stability where subjected to expected building envi-

ronmental conditions, duct movement under general

operating conditions, and duct movement as a result

of interior and exterior fire conditions. [NFPA

96:7.7.2.2.5]

510.7.32.2 Protection from Physical Damage.Measures shall be taken to prevent physical damage

to any a covering or enclosure material. A damage to

the covering or enclosure shall be repaired and the

covering or enclosure shall be restored to meet its

intended listing and fire-resistive rating and to be

acceptable to the Authority Having Jurisdiction.

[NFPA 96:7.7.3.1, 7.7.3.2]

510.7.32.3 Inspection. In the event of a fire

within a kitchen exhaust system, the duct, the enclo-

sure, or the covering directly applied to the duct

shall be inspected by qualified personnel to deter-

mine whether the duct, the enclosure, and the

covering directly applied to the duct are structurally

sound, capable of maintaining their fire protection

functions, suitable for continued operation, and

acceptable to the Authority Having Jurisdiction.

[NFPA 96:7.7.3.3]

510.7.43 Listed. For listed grease ducts, see Section510.4.

510.7.54 Fire Doors. Where enclosure walls areprovided, they shall be protected by listed fire doors ofproper rating. Fire doors shall be installed in accordancewith NFPA 80. 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.[NFPA 96:7.7.4.1 - 7.7.4.3]

510.7.65 Fire Zone. Each duct system shall constitutean individual system serving only exhaust hoods in onefire zone on one floor. Multiple ducts shall not bepermitted in a single enclosure unless acceptable to theAuthority Having Jurisdiction. [NFPA 96:7.7.5.1, 7.7.5.2]

510.8 Termination of Exhaust System. 510.8.1 Termi-nation. The exhaust system shall terminate as follows: [NFPA96:7.8.1]:

(1) Outside the building with a fan or duct. [NFPA 96:7.8.1(1)]

(2) Through the roof, or to the roof from outside, as in Section510.8.21, or through a wall, as in Section 510.8.32. [NFPA96:7.8.1(2)]

510.8.21 Rooftop Terminations. 510.8.2.1Minimum. Rooftop terminations shall be arranged withor provided with the following: [NFPA 96:7.8.2.1]:

(1) Not less than 10 feet (3048 mm) of clearance fromthe outlet to adjacent buildings, property lines, andair intakes. Where space limitations absolutelyprevent a 10 foot (3048 mm) horizontal separationfrom an air intake, a vertical separation shall bepermitted, with the exhaust outlet being not less than3 feet (914 mm) above any an air intake locatedwithin 10 feet (3048 mm) horizontally.

(2) The exhaust flow directed up and away from thesurface of the roof and not less than 40 inches (1016mm) above the roof surface.

(3) The ability to drain grease out of traps or low pointsformed in the fan or duct near the termination of thesystem into a collection container that is noncom-bustible, closed, rainproof, structurally sound for theservice to which it is applied, and will not sustaincombustion. A grease collection device that is appliedto exhaust systems shall not inhibit the performanceof any a fan.

Exception: Grease containers that are evaluated forequivalency with the preceding requirements andlisted as such. [NFPA 96:7.8.2.1(4), 7.8.2.1(5)]


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(4) A listed grease duct listed in accordance with Section510.4, or with ductwork constructed in accordancewith Section 510.5. [NFPA 96:7.8.2.1(7)

(5) A hinged upblast fan supplied with flexible weather-proof electrical cable and service hold-open retainerto permit proper inspection and cleaning that is listedfor commercial cooking equipment, provided the duct-work extends not less than 18 inches (457 mm) abovethe roof surface and the fan discharges not less than40 inches (1016 mm) above the roof surface. (SeeSection 511.1.1.)

(6) Other approved fan, provided:

(a) It meets the requirements of Section 510.8.2.1(3)and Section 511.1.3.

(b) Its discharge or its extended duct discharge meetsthe requirements of Section 510.8.2.1(2).

510.8.2.21.1 Listed Flexible Connetors. Listedflexible connectors shall be permitted to be used onexterior roof locations where required for properequipment vibration isolation.

510.8.2.31.2 Inspection and Cleaning. Fansshall be provided with safe access and a work surfacefor inspection and cleaning. [NFPA 96:7.8.2.2]

510.8.32 Wall Terminations. 510.8.3.1 Minimum.Wall terminations shall be arranged with or provided withthe following properties [NFPA 96:7.8.3]:

(1) Through a noncombustible wall with not less than 10feet (3048 mm) of clearance from the outlet to adja-cent buildings, property lines, grade level, combustibleconstruction, electrical equipment or lines, and theclosest point of any an air intake or operable door orwindow at or below the plane of the exhaust termina-tion. The closest point of any an air intake or operabledoor or window above the plane of the exhaust termi-nation shall be not less than 10 feet (3048 mm) indistance, plus 3 inches (76 mm) for each 1 degree(0.017 rad) from horizontal, the angle of degree beingmeasured from the center of the exhaust termination tothe center of the air intake, operable door or window.(See Figure 510.8.3.12) [NFPA 96:7.8.3(1), 7.8.3(2)]

Exception: A wall termination in a secured area shallbe permitted to be at a lower height above grade whereacceptable to the Authority Having Jurisdiction.[NFPA 96:7.8.3(3)]

(2) The exhaust flow directed perpendicularly outwardfrom the wall face or upward. [NFPA 96:7.8.3(4)]

(3) Ductwork pitched to drain the grease back into thehood(s), or with a drain provided to bring the greaseback into a container within the building or into aremote grease trap. [NFPA 96:7.8.3(5)]

(4) A grease duct listed in accordance with Section510.4, or other ducts constructed in accordance withSection 510.5. [NFPA 96:7.8.3(6)]

(5) An approved fan, provided it meets the requirementsof Section 510.8.3.12(3) and Section 511.1.1 orSection 511.1.3. [NFPA 96:7.8.3(7)]

510.9 Solid-Fuel Duct Systems. Where solid-fuelcooking equipment is to be vented, the duct system shall be inaccordance with Section 517.0.

511.0 Air Movement.

511.1 Exhaust Fans for Commercial Cooking Equip-ment. Where solid-fuel cooking equipment is to be vented,the duct system shall be in accordance with Section 517.0.

511.1.1 Upblast Fans. Approved upblast fans withmotors surrounded by the airstream shall be hinged,supplied with flexible weatherproof electrical cable andservice hold-open retainers, and listed for this use. (SeeFigure 511.1.1) Installation shall conform to the require-ments of comply with 510.8. [NFPA 96:8.1.1.1, 8.1.1.2]

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

Notes:

1. Fresh air intake (FAI) applies to any an air intake, including an operable

door or window.

2. Example:

FAI is same plane as exhaust or lower: 10 feet (min.) between closet

edges.

FAI above plane of exhaust: 10 feet + 0.25 feet

FIGURE 510.8.3.12EXHAUST TERMINATION DISTANCE FROM FRESH AIR INTAkE

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

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511.1.2 In-Line Exhaust Fans. 511.1.2.1 Installa-tion. In-line fans shall be of the type with the motor

located outside the airstream and with belts and pulleys

protected from the airstream by a grease-tight housing.

They shall be connected to the exhaust duct by flanges

securely bolted as shown in Figure 511.1.2.1(a1) through

Figure 511.1.2.1(d4), or by a system specifically listed

for such use. Flexible connectors shall not be used.

[NFPA 96:8.1.2.1 – 8.1.2.3]

FIGURE 511.1.1UPBLAST FAN CLEARANCES.

[NFPA 96:7.8.2.1]

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

FIGURE 511.1.2.1(a1)TYPICAL SECTION OF DUCT-TO-FAN CONNECTION–BUTT JOINT METHOD.

[NFPA 96:8.1.2.2(a)]

For SI units: 1 inch = 25.4 mm, t/°C=(t/°F-32)/1.8

EXHAUST SYSTEMS

FIGURE 511.1.2.1(c3)

TYPICAL SECTION OF DUCT-TO-FAN CONNECTION–

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

FIGURE 511.1.2.1(d4)

TYPICAL SECTION OF DUCT-TO-FAN CONNECTION–DIRECT

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



FIGURE 511.1.2.1(b2)

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

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


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511.1.2.21 Accessibility. Where the design orpositioning of the fan allows grease to be trapped, adrain directed to a readily accessible and visiblegrease receptacle, not exceeding 1 gallon (3.8 L),shall be provided. In-line exhaust fans shall belocated in an easily accessible area of adequateapproved size to allow for service or removal.Where the duct system connected to the fan is in anenclosure, the space or room in which the exhaustfan is located shall have the same fire resistancerating as the enclosure. [NFPA 96:8.1.2.4 - 8.1.2.6]

511.1.3 Utility Set Exhaust Fans. Utility set exhaustfans shall be installed in accordance with Section511.1.3.1 through Section 511.1.3.3.

511.1.3.1 At the Rooftop. Fans installed at therooftop termination point shall be in accordancewith the following:

(1) Section 510.8.2.1(1) and Section 510.8.2.31.2.

(2) Flexible connectors shall be permitted.

(3) A drain shall be directed to a readily accessibleand visible grease receptacle not to exceed 1gallon (3.8 L).

511.1.3.2 Within the Building. Fans installedwithin the building shall be in accordance with thefollowing:

(1) Located in an easily accessible area of adequatesize to allow for service or removal.

(2) Flexible connectors shall be prohibited.

(3) A drain shall be directed to a readily accessibleand visible grease receptacle not to exceed 1gallon (3.8 L). [NFPA 96:8.1.3.1 - 8.1.3.6]

511.1.3.3 Duct Systems. Duct systems, connectedto fans, in an enclosure shall be in accordance withthe following:

(1) The space or room in which the exhaust fan islocated shall have the same fire resistance ratingas the enclosure.

(2) The fan shall be connected to the exhaust ductby flanges securely bolted as shown in Figure511.1.2.1(a1) through Figure 511.1.2.1(d4) orby a system specifically listed for such use.

511.1.4 Construction. Exhaust fan housings shall beconstructed of carbon steel not less than 0.054 of an inch(1.37 mm) (No. 16 MSG) in thickness or stainless steelnot less than 0.043 of an inch (1.09 mm) (No. 18 MSG) inthickness or, where listed, constructed in accordance withthe terms of the listing. [NFPA 96:8.1.4]

511.1.5 Miscellaneous. Openings for cleaning, serv-icing, and inspection shall be in accordance with therequirements of Section 510.3.32. Clearances shall be inaccordance with the requirements of Section 507.2, orSection 510.7.21.3 if where installed within an enclosure.[NFPA 96:8.1.5.1, 8.1.5.2]

511.1.6 Standard. Wiring and electrical equipmentshall be in accordance comply with NFPA 70.

511.2 Airflow. 511.2.1 Velocity. The air velocity throughany a duct shall be not less than 500 feet per minute (ft/min)(152.4 meters per minute 2.54 m/s) and not exceed 2500feet per minute (ft/min) (12.7 m/s).

511.2.21 Exceptions. Transition duct sections that donot exceed 3 feet (914 mm) in length and do not containgrease traps shall be permitted to be connected to hoodsand exhaust fans that do not meet this velocity. [NFPA96:8.2.1.2]

511.2.32 Exhaust-Air Volumes. Exhaust-air volumesfor hoods shall be of sufficient level to provide for captureand removal of grease-laden cooking vapors. Test data,performance acceptable to tests approved by theAuthority Having Jurisdiction, or both, shall be provided,displayed, or both, upon request. [NFPA 96:8.2.2.1,8.2.2.2]

Exception: Lower exhaust-air volumes shall be permittedduring no-load cooking conditions, provided they aresufficient to capture and remove flue gases and residualvapors from cooking equipment. [NFPA 96:8.2.2.3]

511.2.43 Operation. A hood exhaust fan(s) shallcontinue to operate after the extinguishing system hasbeen activated, unless fan shutdown is required by a listedcomponent of the ventilation system or by the design ofthe extinguishing system. The hood exhaust fan shall notbe required to start upon activation of the extinguishingsystem where the exhaust fan and all cooking equipmentserved by the fan have previously been shut down. [NFPA96:8.2.3.1 - 8.2.3.2]

511.3 Replacement Air. Replacement air quantity shall beadequate sufficient to prevent negative pressures in thecommercial cooking area(s) from exceeding 0.02 inch watercolumn (4.98 kPa). Where its fire-extinguishing systemdischarges activates, makeup air supplied internally to a hoodshall be shut off. [NFPA 96:8.3.1 - 8.3.2]

Exception: Compensating hoods shall meet the airflowrequirements specified in Section 508.4.1.3 through Section508.4.1.5. Compensating hoods shall extract not less than 20percent of their required exhaust airflow from the kitchen area.

511.4 Common Duct (Manifold) Systems. 511.4.1Multiple Tenants. Master kitchen exhaust ducts that servemultiple tenants shall include provision to bleed air fromoutdoors or 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]

511.4.21 Connections. The bleed-air ducts shallconnect to the top or side of the master exhaust duct. [NFPA96:8.4.2]

511.4.32 Fire Damper. The bleed-air duct shall have a

fire damper not less than 12 inches (305 mm) from the

exhaust duct connection. [NFPA 96:8.4.3]

511.4.43 Construction and Clearance. The bleed-air

duct shall have the same construction and clearance

requirements as the main exhaust duct from the connection

to the exhaust duct to not less than 12 inches (305 mm) on

both sides of the fire damper. [NFPA 96:8.4.4]

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511.4.54 Adjustment. Each bleed air duct shall have a

means of adjusting (e.g., using volume dampers) the bleed-

air quantity. [NFPA 96:8.4.5]

511.4.65 Adjustment Location. Means to adjust the

bleed air quality shall be installed in between the fire

damper and the source of bleed air. [NFPA 96:8.4.6]

511.4.76 Bleed Air Duct. A bleed air duct shall not be

used for the exhaust of grease-laden vapors and shall be so

labeled. [NFPA 96:8.4.7]

511.4.87 Disconnect. Unused tenant exhaust connec-

tions to the master exhaust duct that are not used as bleed

air connections shall be disconnected and sealed at the main

duct. [NFPA 96:8.4.8]

511.5 Solid-Fuel Air Movement Requirements. Where

solid-fuel cooking equipment is used, exhaust and replacement

air also shall be in accordance with Section 517.0.

512.0 Auxiliary Equipment.

512.1 Dampers. Dampers shall not be installed in exhaust

ducts or exhaust duct systems. [NFPA 96:9.1.1]

512.1.1 Use. Where specifically listed for such use or

where required as part of a listed device or system, dampers

in exhaust ducts or exhaust duct systems shall be permitted.

[NFPA 96:9.1.2]

512.2 Electrical Equipment. 512.2.1 Wiring Systems.Wiring systems of any type shall not be installed in ducts.

[NFPA 96:9.2.1]

512.2.21 Device Installation in Ducts. Only wWhere

specifically listed for such use shall motors, lights, and

other electrical devices shall be permitted to be installed in

ducts or hoods or located in the path of travel of exhaust

products. [NFPA 96:9.2.2]

512.2.32 Location. Lighting units on hoods shall not be

located in concealed spaces except as permitted by Section

512.2.43 and Section 512.2.54. [NFPA 96:2.3.2].

512.2.43 Concealed Spaces. Lighting units shall be

permitted in concealed spaces where such units are part of

a listed exhaust hood. [NFPA 96:9.2.3.3]

512.2.54 Listed Lighting Units. Listed lighting units

specifically listed for such use and installed in accordance

with the terms of the listing shall be permitted to be

installed in concealed spaces. [NFPA 96:9.2.3.4]

512.2.65 Standard. Electrical equipment shall be

installed in accordance with NFPA 70, with due regard to

the effects of heat, vapor, and grease on the equipment.

512.3 Other Equipment. 512.3.1 Shared Ducts/Hoods.Fume incinerators, thermal recovery units, air pollution control

devices, or other devices shall be permitted to be installed in

ducts, hoods or to be located in the path of travel of exhaust

products where specifically approved for such use. Down-

grading other parts of the exhaust system due to the installation

of these approved devices, whether listed or not, shall not be

allowed. [NFPA 96:9.3.1 - 9.3.2]

512.3.21 Fire-Extinguishing System. An equipment,listed or otherwise, that provides secondary filtration or airpollution control and that is installed in the path of travel ofexhaust products shall be provided with an approved auto-matic fire-extinguishing system, installed in accordancewith fire-extinguishing system manufacturer’s installationinstructions, for the protection of the component sections ofthe equipment and shall include protection of the ductworkdownstream of the equipment, whether or not the equip-ment is provided with a damper. Filter media used insecondary filtration or air pollution control units and not inaccordance with Section 509.2.43 shall have fire protec-tion that is adequate for the filter media being used in accor-dance with the fire-extinguishing system manufacturer’sinstallation instructions. Where the equipment provides asource of ignition, it shall be provided with a detection tooperate the fire-extinguishing system protecting the equip-ment. [NFPA 96:9.3.3, 9.3.3.1, 9.3.4]

512.3.32 Air Recirculation. Where a cooking exhaustsystem employs an air pollution control device that recir-culates air into the building, the requirements of Section516.0 shall apply. [NFPA 96:9.3.5]

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

513.0 Fire-Extinguishing Equipment.

513.1 General. Fire-extinguishing equipment for the protec-tion of grease removal devices, hood exhaust plenums, andexhaust duct systems shall be provided. [NFPA 96:10.1.1]

513.1.1 Protection. Cooking equipment that producesgrease-laden vapors (such as, but not limited to, deep-fatfryers, ranges, griddles, broilers, woks, tilting skillets, andbraising pans) and can be a source of ignition of grease inthe hood, grease removal device, or duct shall be protectedby fire-extinguishing equipment. [NFPA 96:10.1.2]

513.2 Types of Equipment. 513.2.1 Fire Protection.Fire-extinguishing equipment shall include both automaticfire-extinguishing systems as primary protection and portablefire extinguishers as secondary backup. [NFPA 96:10.2.1]

513.2.1.1 Identification. A placard identifying the useof the extinguisher as secondary backup to the automaticfire-extinguishing system shall be conspicuously placednear each portable the fire extinguisher in the cookingarea that states that the fire protection system shall be acti-vated prior to using the fire-extinguisher. [NFPA96:10.2.2]

513.2.2 Standard. Automatic fire-extinguishingsystems shall be installed in accordance with standardUL 300 or other equivalent standards and shall beinstalled in accordance with the requirements of thelisting. [NFPA 96:10.2.3]

Exception: Automatic fire-extinguishing equipmentprovided as part of listed recirculating systems in accor-dance with UL 710B. [NFPA 96:10.2.6]

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513.2.2.1 Installation. Automatic fire-extin-guishing systems shall be installed in accordancewith the terms of their listing, the manufacturer’sinstallation instructions, and the following standardswhere applicable. [NFPA 96:10.2.6]:

(1) NFPA 12

(2) NFPA 13

(3) NFPA 17

(4) NFPA 17A

513.2.3 Existing Systems. In existing systems,where changes in the cooking media, positioning, orreplacement of cooking equipment occur, the fire-extin-guishing system shall be made in accordance withSection 513.2.2. [NFPA 96:10.2.3.1]

513.2.4 Modification of Existing Hood Systems.513.2.4.1 Previous Installation. An abandoned pipeor conduit from a previous installation shall be removedfrom within the hood, plenum, and exhaust duct. [NFPA96:10.2.7.1]

513.2.4.21 Sealing. Penetrations and holes resultingfrom the removal of conduit or piping shall be sealedwith listed or equivalent liquid tight sealing devices.[NFPA 96:10.2.7.2]

513.2.4.32 Obstructions. The addition of obstruc-tions to spray patterns from the cooking appliancenozzle(s) such as baffle plates, shelves, or any a modi-fication shall not be permitted. [NFPA 96:10.2.7.3]

513.2.4.43 System Re-evaluation. Changes or

modifications to the hazard after installation of the

fire-extinguishing systems shall result in re-evalua-

tion of the system design by a properly trained, qual-

ified, and certified person(s). [NFPA 96:10.2.7.4]

513.2.5 Fixed Baffle Hoods with Water Wash.Grease removal devices, hood exhaust plenums, and

exhaust ducts requiring protection in accordance with

Section 513.1.1 shall be permitted to be protected by a

listed fixed baffle hood containing a constant or fire-actu-

ated water wash system that is listed and in accordance

with UL 300 or other equivalent standards and shall be

installed in accordance with the requirements of their

listing. [NFPA 96:10.2.8.1]

513.2.5.1 Domestic Water Supply. The water

for listed, fixed baffle hood assemblies shall be

permitted to be supplied from the domestic water

supply where the minimum water pressure and flow

are provided in accordance with the terms of the

listing. [NFPA 96:10.2.8.3]

513.2.5.2 Control Valve. The water supply shallbe controlled by a supervised water supply controlvalve. [NFPA 96:10.2.8.4]

513.2.5.3 Activation. The water wash in the fixedbaffle hood specifically listed to extinguish a fireshall be activated by the cooking equipment extin-guishing system. [NFPA 96:10.2.8.5]

513.2.5.4 Water-Wash System. A water-wash

system approved to be used for protection of the

grease removal device(s), hood exhaust plenum(s),

exhaust duct(s), or combination thereof shall include

instruction and appropriate electrical interface for

simultaneous activation of the water-wash system

from an automatic fire-extinguishing system, where

the automatic fire-extinguishing system is used for

cooking equipment protection only. [NFPA

96:10.2.8.6]

513.2.5.5 Activation, Exception. Where the fire-

extinguishing system provides protection for the

cooking equipment, hood, and duct, activation of the

water-wash shall not be required. [NFPA 96:10.2.8.7]

513.2.5.6 Water Supply. The water required for

listed automatic fire-extinguishing systems shall be

permitted to be supplied from the domestic water

supply where the minimum water pressure and flow

are provided in accordance with the terms of the

listing. The water supply shall be controlled by a

supervised water supply control valve. [NFPA

96:10.2.9]

513.2.6 Water Valve Supervision. Valves controlling

the water supply to listed fixed baffle hood assemblies,

automatic fire-extinguishing systems, or both shall be

listed indicating type of valve and shall be supervised open

by one of the following methods: [NFPA 96:10.2.10]:

(1) Central station, proprietary, or remote station alarm

service. [NFPA 96:10.2.10(1)]

(2) Local alarm service that will cause the sounding of

an audible signal at a constantly attended point.

[NFPA 96:10.2.10(2)]

(3) Locking valves open. [NFPA 96:10.2.10(3)]

(4) Sealing of valves and approved weekly recorded

inspection. [NFPA 96:10.2.10(4)]

513.3 Simultaneous Operation. Fixed-pipe extinguishing

systems in a single hazard area shall be arranged for simulta-

neous automatic operation upon actuation of any one of the

systems. [NFPA 96:10.3.1]

513.3.1 Automatic Sprinkler System. Simultaneous

operation shall not be required where the fixed pipe

extinguishing system is an automatic sprinkler system.

[NFPA 96:10.3.2]

513.3.2 Dry or Wet Chemical Systems. Simulta-

neous operation shall not be required where a dry or wet

chemical system shall be permitted to be is used to protect

common exhaust ductwork by one of the methods specified

in NFPA 17 or NFPA 17A. [NFPA 96:10.3.3]

513.4 Fuel Shutoff. 513.4.1 Automatic Shut Off. Upon

activation of any a fire-extinguishing system for a cooking oper-

ation, all sources of fuel and electric power that produce heat to

all equipment requiring protection by that system shall auto-

matically shut off. [NFPA 96:10.4.1]

Exception: Solid-fuel cooking operations.

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513.4.21 Steam. Steam supplied from an external sourceshall not be required to automatically shut off. [NFPA96:10.4.2]

513.4.32 Protection Not Required. A gas appliancenot requiring protection, but located under the same venti-lating equipment, shall also automatically shut off uponactivation of an extinguishing system. [NFPA 96:10.4.3]

513.4.43 Manual Reset. Shutoff devices shall requiremanual reset. [NFPA 96:10.4.4]

513.5 Manual Activation. A readily accessible means formanual activation shall be located between 42 inches and 48inches (1067 mm and 1219 mm) above the floor, be accessiblein the event of a fire, be located in a path of egress, and clearlyidentify the hazard protected. A manual actuation device shall belocated not less than 10 feet (3048 mm) where possible and lessthan 20 feet (6096 mm) from the protected kitchen appliance(s)within the path of egress. Manual actuation using a cable-oper-ated pull station shall t require not more than 40 pounds (178 N)of force, with a pull movement not to exceed 14 inches (356mm) to actuate activate the automatic fire suppression extin-guishing system. The automatic and manual means of systemactivation external to the control head or releasing device shallbe separate and independent of each other so that failure of onewill not impair the operation of the other. [NFPA 96:10.5.1 –10.5.2]

513.5.1 Location of Manual Activation Device. Themanual means of system activation shall be permitted to becommon with the automatic means where the manual acti-vation device is located between the control head orreleasing device and the first fusible link. [NFPA 96:10.5.3]

513.5.2 Automatic Sprinkler System. An automaticsprinkler system shall not require a manual means ofsystem activation. [NFPA 96:10.5.4]

513.5.3 Manual Actuator(s). The means for manualactuator shall be mechanical or rely on electrical power foractivation in accordance with Section 513.5.4. [NFPA96:10.5.5]

513.5.4 Standby Power Supply. Electrical power shallbe permitted to be used for manual activation where astandby power supply is provided or if where supervisionis provided in accordance with Section 513.7. [NFPA96:10.5.6]

513.6 System Annunciation. 513.6.1 AudibleAlarm/Visual Indicator. Upon activation of an automatic fireextinguishing system, an audible alarm or visual indicator shallbe provided to show that the system has activated. [NFPA96:10.6.1]

513.6.21 Signaling. Where a fire alarm signaling systemis serving the occupancy where the extinguishing system islocated, the activation of the automatic fire-extinguishingsystem shall activate the fire alarm signaling system.[NFPA 96:10.6.2]

513.7 System Supervision. 513.7.1 Power Supply.Where electrical power is required to operate the automatic fire-extinguishing system, the system shall be monitored by a super-visory alarm, with a standby power supply provided inaccordance with Section 513.7.1. [NFPA 96:10.7.1]

513.7.21 Backup Detection System AutomaticFire-Extinguishing System. System supervision shallnot be required where an automatic fire-extinguishingsystem(s) includes automatic mechanical detection andactuation as a backup detection system Where a fixed auto-matic fire-extinguishing system includes automaticmechanical detection and actuation as a backup detectionsystem, electrical power monitoring and reserve powersupply shall not be required. [NFPA 96:10.7.2]

513.7.32 Supervision. System supervision shall not berequired where a fire-extinguishing system(s) is intercon-nected or interlocked with the cooking equipment powersource(s) so that if the fire extinguishing system becomesinoperable due to power failure, all sources of fuel or elec-tric power that produce heat to all cooking equipment serv-iced by that hood shall automatically shut off. [NFPA96:10.7.3]

513.7.43 Listed Water Wash System. System super-vision shall not be required where an automatic fire-extin-guishing system, including automatic mechanical detectionand actuation, is electrically connected to a listed fire-actu-ated water-wash system for simultaneous operation of bothsystems. [NFPA 96:10.7.4]

513.8 Special Design and Application. 513.8.1Protected Areas. Hoods containing automatic fire extin-guishing systems are protected areas; therefore, these hoods arenot considered obstructions to overhead sprinkler systems andshall not require floor coverage underneath. [NFPA 96:10.8.1]

513.8.21 Single Device.A single listed detection device,listed with the extinguishing system, shall be permitted formore than one appliance where installed in accordance withthe terms of the listing. [NFPA 96:10.8.2]

513.9 Review and Certification. 513.9.1 CompleteDrawings. Where required, complete drawings of the systeminstallation, including the hood(s), exhaust duct(s), and appli-ances, along with the interface of the fire-extinguishing systemdetectors, piping, nozzles, fuel shutoff devices, agent storagecontainer(s), and manual actuation device(s), shall be submittedto the Authority Having Jurisdiction. [NFPA 96:10.9.1]

513.10 Installation Requirements. 513.10.1 qualifiedPersons. Installation of systems shall be performed only bypersons properly trained and qualified to install the specificsystem being provided. The installer shall provide certificationto the Authority Having Jurisdiction that the installation is inagreement with the terms of the listing and the manufacturer’sinstallation instructions, approved design, or both. [NFPA96:10.9.2]

513.11 Portable Fire Extinguishers. 513.11.1 Installa-tion and Recommendation. Portable fire extinguishersshall be installed in kitchen cooking areas in accordance withNFPA 10 and shall be specifically listed for such use. Suchextinguishers shall use agents that saponify upon contact withhot grease, such as sodium bicarbonate and potassium bicar-bonate dry chemical and potassium carbonate solutions. ClassB gas-type portables shall not be permitted in kitchen cookingareas. Manufacturer’s recommendations shall be followedand shall be maintained in accordance with NFPA 10. [NFPA96:10.10.1-10.10.2, 10.10.4]

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513.11.1.1 Permitted Use. Portable fire extinguisherslisted specifically for use in the kitchen cooking areasshall also be permitted.

513.11.2 Other Fire Extinguishers. Other fire extin-guishers in the kitchen area shall be installed in accor-dance with NFPA 10. [NFPA 96:10.10.53]

513.12 Solid-Fuel Fire-Extinguishing Equipment.Where solid-fuel cooking equipment is served by fire extin-guishing equipment, the provisions of Section 517.0 shall apply.

514.0 Procedures for the Use, Inspection, Testing,and Maintenance of Equipment.

514.1 Operating Procedures. 514.1.1 Operation.Exhaust systems shall be operated where cooking equipmentis turned on. [NFPA 96:11.1.1]

514.1.21 Filters. Filter-equipped exhaust systems shallnot be operated with filters removed. [NFPA 96:11.1.2]

514.1.32 Openings. Openings provided for replacingair exhausted through ventilating equipment shall not berestricted by covers, dampers, or other means that wouldreduce the operating efficiency of the exhaust system.[NFPA 96:11.1.3]

514.1.43 Posting of Instructions. Instructions formanually operating the fire-extinguishing system shallbe posted conspicuously in the kitchen and shall bereviewed periodically with employees by the manage-ment. [NFPA 96:11.1.4]

514.1.54 Listing and Manufacturer’s Instruc-tions. Listed exhaust hoods shall be operated in accor-dance with the terms of their listings and themanufacturer's instructions. [NFPA 96:11.1.5]

514.1.65 Non Operation. Cooking equipment shallnot be operated while its fire-extinguishing system orexhaust system is nonoperational or otherwise impaired.[NFPA 96:11.1.6]

514.1.76 Secondary Control Equipment.Secondary filtration and pollution control equipmentshall be operated in accordance with the terms of itslisting and the manufacturer's recommendations instruc-tions. [NFPA 96:11.1.7]

514.1.87 Inspection Frequency. Inspection andmaintenance of equipment allowed in Section 512.3.1shall be conducted by properly trained and qualifiedpersons at a frequency determined by the manufacturer'sinstructions or equipment listing. [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 certifiedperson(s) or company acceptable to the Authority Having Juris-diction not less than every 6 months. [NFPA 96:11.2.1]

514.2.1 Requirements. Actuation components,

including remote manual pull stations, mechanical or elec-

trical devices, detectors and actuators shall be checked for

proper operation during the inspection in accordance with

the manufacturer’s listed procedures instructions. In addi-

tion to these requirements, the specific inspection and

maintenance requirements of the extinguishing system

standards as well as the applicable listed installation and

maintenance manuals and service bulletins shall be

followed. [NFPA 96:11.2.2 - 11.2.3]

514.2.2 Fusible Links and Sprinkler Heads.Fusible links of metal alloy and automatic sprinklerheads of metal alloy shall be replaced not less thansemiannually, or more frequently if necessary whererequired by the manufacturer except as permitted bySection 514.2.3 and Section 514.2.4. [NFPA 96:11.2.4]

514.2.3 Inspection Tag. The year of manufacture andthe date of installation of the fusible links shall bemarked on the system inspection tag. The tag shall besigned or initialed by the installer. [NFPA 96:11.2.5 -11.2.5.1]

Detection devices other than fusible links and auto-matic sprinklers shall be serviced or replaced in accor-dance with the manufacturer’s recommendationsinstructions. [NFPA 96:11.2.6]

514.2.4 Annual Replacement Temperature-Sensing Elements. Where automatic bulb-type sprin-klers or spray nozzles are used and annual examinationshows no buildup of grease or other material on the sprin-kler or spray nozzles, annual replacement shall not berequired Fixed temperature-sensing elements other thanthe fusible metal alloy type shall be permitted to remaincontinuously in service, provided they are inspected,cleaned, and replaced in accordance with the manufac-turer’s instructions every 12 months to ensure operationof the system as designed. [NFPA 96:11.2.7]

514.2.5 Certification. Where required, certificates ofinspection and maintenance shall be forwarded to theAuthority Having Jurisdiction. [NFPA 96:11.2.8]

514.3 Inspection for Grease Buildup. 514.3.1Acceptable Inspectors. The entire exhaust system shallbe inspected for grease buildup by a trained, qualified, andcertified company or person(s) acceptable to the AuthorityHaving Jurisdiction and in accordance with Table 514.3.1.[NFPA 96:11.4]

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 cooking

operations.

Semi-annually

Systems serving low-volume cooking opera-

tions, such as churches, day camps, seasonal

businesses, or senior centers.

Annually

TABLE 514.3.1

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[NFPA 96: TABLE 11.4]

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514.4 Cleaning of Exhaust Systems. 514.4.1 Prop-erly Cleaned. Upon inspection, where the exhaust systemis found to be contaminated with deposits from grease-ladenvapors, the contaminated portions of the exhaust system shallbe cleaned by a trained, qualified, and certified company orperson(s) acceptable to the Authority Having Jurisdiction.[NFPA 96:11.6.1]

514.4.21 Removal of Contaminants. Hoods, greaseremoval devices, fans, ducts, and other appurtenancesshall be cleaned to remove combustible contaminant'sprior to surfaces becoming heavily contaminated withgrease or oily sludge. [NFPA 96:11.6.2]

514.4.32 Electrical Switches. At the start of thecleaning process, electrical switches that could be acti-vated accidentally shall be locked out. [NFPA 96:11.6.3]

514.4.43 Fire Suppression System. Componentsof the fire suppression system shall not be rendered inop-erable during the cleaning process. [NFPA 96:11.6.4]

514.4.54 Inoperable. Fire-extinguishing systems shallbe permitted to be rendered inoperable during thecleaning process where serviced by trained and qualifiedpersons. [NFPA 96:11.6.5]

514.4.65 Solvents/Cleaning Aids. Flammablesolvents or other flammable cleaning aids shall not beused. [NFPA 96:11.6.6]

514.4.76 Cleaning Chemicals. Cleaning chemicalsshall not be applied on fusible links or other detectiondevices of the automatic extinguishing system. [NFPA96:11.6.7]

514.4.87 Coating. After the exhaust system is cleaned,it shall not be coated with powder or other substance.[NFPA 96:11.6.8]

514.4.98 Access Panels and Cover Plates. Wherecleaning procedures are completed, all access panels(doors) and cover plates shall be restored to their normaloperational condition. [NFPA 96:11.6.9]

514.4.109 Date of Inspection. Where an access panelis removed, a service company label or tag pre-printedwith the name of the company and giving the date ofinspection or cleaning shall be affixed near the affectedaccess panels. [NFPA 96:11.6.10]

514.4.110 Airflow. Dampers and diffusers shall bepositioned for proper airflow. [NFPA 96:11.6.11]

514.4.121 Operable State. Where cleaning proce-dures are completed, all electrical switches and systemcomponents shall be returned to an operable state. [NFPA96:11.6.12]

514.4.132 Certification of Service. Where anexhaust cleaning service is used, a certificate showingthe name of the servicing company, the name of theperson performing the work, and the date of inspection orcleaning shall be maintained on the premises. [NFPA96:11.6.13]

514.4.143 Report Provided. After cleaning or inspec-tion is completed, the exhaust cleaning company and the

person performing the work at the location shall providethe owner of the system with a written report that alsospecifies areas that were inaccessible, or not cleaned, orboth. [NFPA 96:11.6.14]

514.4.154 Unclean Area. Where required, certificatesof inspection and cleaning and reports of areas notcleaned shall be submitted to the Authority Having Juris-diction. [NFPA 96:11.6.15]

515.0 Minimum Safety Requirements for CookingEquipment.

515.1 Cooking Equipment. 515.1.1 Approval. Cookingequipment shall be approved based on one of the followingcriteria: [NFPA 96:12.1.1]:

(1) Listings by a testing laboratory. [NFPA 96:12.1.1(1)]

(2) Test data acceptable to the Authority Having Jurisdiction.[NFPA 96:12.1.1(2)]

515.1.21 Installation. 515.1.2.1 Listings andManufacturer’s Instructions. Listed appliances shallbe installed in accordance with the terms of their listingsand the manufacturer's installation instructions. [NFPA96:12.1.2.1]

515.1.21.21 Reevaluation. Cooking appliancesrequiring protection shall not be moved, modified,or rearranged without prior reevaluation of the fire-extinguishing system by the system installer or serv-icing agent, unless otherwise allowed by the designof the fire-extinguishing system. [NFPA 96:12.1.2.2]

515.1.21.32 Prior Location. The fire-extinguishingsystem shall not require re-evaluation where thecooking appliances are moved to perform mainte-nance and cleaning provided the appliances arereturned to approved design location prior to cookingoperations, and any a disconnected fire-extinguishingsystem nozzles attached to the appliances are recon-nected in accordance with the manufacturer’s listeddesign manual instructions. [NFPA 96:12.1.2.3]

515.1.21.43 Minimum Space. All dDeep-fatfryers shall be installed with not less than a 16 inch(406 mm) space between the fryer and surface flamesfrom adjacent cooking equipment. [NFPA96:12.1.2.4]

515.1.21.54 Space Not Required. Where a steelor tempered glass baffle plate is installed not lessthan 8 inches (203 mm) in height between the fryerand surface flames of the adjacent appliance, therequirement for a 16 inch (406 mm) space shall notapply. [NFPA 96:12.1.2.5]

515.1.21.65 Minimum Height. Where the fryerand the surface flames are at different horizontalplanes, a height of not less than 8 inches (203 mm)shall be measured from the higher of the two.[NFPA 96:12.1.2.5.1]

515.2 Operating Controls. Deep-fat fryers shall beequipped with a separate high-limit control in addition to the

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adjustable operating control (thermostat) to shut off fuel orenergy where the fat temperature reaches 475°F (246°C) at 1inch (25.4 mm) below the surface. [NFPA 96:12.2]

515.3 Cooking Equipment Maintenance. 515.3.1Inspection and Servicing. An inspection and servicingof the cooking equipment shall be made not less than annu-ally by properly trained and qualified persons. [NFPA96:11.7.1]

515.3.21 Cleaning. Cooking equipment that collectsgrease below the surface, behind the equipment, or incooking equipment flue gas exhaust, such as griddles orcharbroilers, shall be inspected and, if found with greaseaccumulation, cleaned by a properly trained, qualified,and certified person acceptable to the aAuthorityhHaving jJurisdiction. [NFPA 96:11.7.2]

516.0 Recirculating Systems.

516.1 General Requirements. Recirculating systemscontaining or for use with appliances used in processesproducing smoke or grease-laden vapors shall be equippedwith components in accordance with the following:

(1) The clearance requirements of Section 507.2.

(2) A hood complying with the requirements of Section508.0.

(3) Grease removal devices complying with Section 509.0.

(4) The air movement requirements of Section 511.2.1 andSection 511.2.21.

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

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

Exception: References to ducts in Section 513.1.1 andSection 513.5.1.

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

(8) The minimum safety requirements of Section 515.0.

(9) The requirements of this chapter. [NFPA 96:13.1]

516.2 Design Restrictions. Recirculating systems shall bein accordance comply with Section 516.2. [NFPA 96:13.2]

516.2.1 Gas/Electrically Fueled Cooking Appli-ances. Only gGas 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 notless than a 18 inch (457 mm) clearance from the flueoutlet to the filter inlet in accordance with Section509.2.32 and shall be in accordance with the installationrequirements of NFPA 54, or NFPA 58. [NFPA 96:13.2.1- 13.2.3]

516.2.2 Recirculation. Recirculating systems shall belisted with a testing laboratory in accordance with UL710B or equivalent. [NFPA 96:13.2.4.1]

516.2.3 Protection. Cooking appliances that require

protection and that are under a recirculating hood shall be

protected by either the integral fire protection system for

the hood or a system in accordance with Section 513.0.

[NFPA 96:13.2.4.2]

516.2.4 Maximum Limits. A recirculating systemshall not use cooking equipment that exceeds that recir-culating system's labeled maximum limits for that type ofequipment, stated in maximum energy input, maximumcooking temperature, and maximum square area ofcooking surface or cubic volume of cooking cavity.[NFPA 96:13.2.6]

516.2.5 Label. The listing label shall show the type(s)of cooking equipment tested and the maximum limitsspecified in Section 516.2.4. [NFPA 96:13.2.7]

516.2.6 Fire Damper. A fire-actuated damper shall beinstalled at the exhaust outlet of the system. The actua-tion device shall have a maximum temperature rating of375°F (1901°C). [NFPA 96:13.2.8, 13.2.10]

516.2.7 Installation of Electrical Wiring. No elec-trical wiring shall be installed in the interior sections ofthe hood plenum that can become exposed to grease.

Exception: As permitted by NFPA 70.

516.2.8 Power Supply. The power supply of an elec-trostatic precipitator (ESP) shall be of the "cold spark,"ferro-resonant type in which the voltage falls off as thecurrent draw of a short increases. [NFPA 96:13.2.11]

516.2.9 Listing Evaluation. Listing evaluation shallinclude the following:

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

(2) Grease discharge at the exhaust outlet of the systemnot to exceed an average of 0.8x10-6 ounce pergallon (5 mg/m3) of exhausted air sampled from thatequipment at maximum amount of product that iscapable of being processed over a continuous 8 hourtest in accordance with EPA Test Method 202, withthe system operating at its minimum listed airflow.

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

(4) Electrical connection in the field in accordance withNFPA 70.

(5) Interlocks on all removable components that lie inthe path of airflow within the unit to ensure that theyare in place during operation of the cooking appli-ance. [NFPA 96:13.2.12]

516.3 Interlocks. The recirculating system shall beprovided with interlocks of all critical components and oper-ations as indicated in Section 516.3.1 through Section 516.3.4such that, if any of these where an interlocks are is inter-rupted, the cooking appliance shall not be able to operate.[NFPA 96:13.3.1]

516.3.1 Airflow Sections. Closure panels encom-passing airflow sections shall have interlocks to ensurethe panels are in place and fully sealed. [NFPA 96:13.3.2]

516.3.2 Filter Component. Each filter component(grease and odor) shall have an interlock to prove thecomponent is in place. [NFPA 96:13.3.3]

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516.3.3 ESP Interlocks. 516.3.3.1 ESP Design.Each ESP shall have a sensor to prove its performance isas designed, with no interruption of the power to exceed2 minutes. [NFPA 96:13.3.4.1]

516.3.3.21 Manual Reset. The sensor shall be amanual reset device or circuit. [NFPA 96:13.3.4.2]

516.3.4 Minimum Airflow. An airflow switch or trans-ducer shall be provided after the last filter component toensure that a minimum airflow is maintained. This deviceopens the interlock circuit where the airflow falls 25percent below the system's normal operating flow or 10percent below its listed minimum rating, whichever islower. This switch or transducer shall be a manual resetdevice or circuit. [NFPA 96:13.3.5.1 - 13.3.5.3]

516.4 Location and Application Restrictions. Thelocation of recirculating systems shall be approved by theAuthority Having Jurisdiction. Items to be reviewed in thefire risk assessment shall include, but not be limited to, lifesafety, combustibility of surroundings, proximity to air vents,and total fuel load. [NFPA 96:13.4.1, 13.4.2]

516.5 Additional Fire Safety Requirements. 516.5.1Listed. In addition to the appliance nozzle(s), a recirculatingsystem shall be listed with the fire protection for grease filters,grease filtration, odor filtration units, and ductwork whereapplicable. [NFPA 96:13.5.1]

516.5.21 Installation Downstream. In addition toother fire-extinguishing system actuation device, thereshall be a fire-extinguishing system actuation deviceinstalled downstream of an ESP. [NFPA 96:13.5.2]

516.5.32 Locations. The requirements of Section513.6 shall also apply to recirculating system locations.[NFPA 96:13.5.3]

516.6 Use and Maintenance. 516.6.1 Interference.Automatic or manual covers on cooking appliances, espe-cially fryers, shall not interfere with the application of the firesuppression system. [NFPA 96:13.6.1]

516.6.21 Manufacturer’s Instructions. Filters shallbe cleaned or replaced in accordance with the manufac-turer's instructions. [NFPA 96:13.6.2]

516.6.32 Cleaning Schedule. ESP’s shall be cleaneda minimum of once per week following in accordancewith the manufacturer's cleaning instructions. [NFPA96:13.6.3]

516.6.43 Hood Plenum and Blower SectionCleaning Schedule. The entire hood plenum and theblower section shall be cleaned, a minimum of not lessthan once every 3 months. [NFPA 96:13.6.4]

516.6.54 Inspection of Safety Interlocks. Inspec-tion and testing of the total operation and all safety inter-locks in accordance with the manufacturer's instructionsshall be performed by qualified service personnel aminimum of not less than once every 6 months, or morefrequently if required. [NFPA 96:13.6.5]

516.6.65 Inspection. Fire-extinguishing equipmentshall be inspected in accordance with Section 514.2.[NFPA 96:13.6.6]

516.6.76 Maintenance Log. A signed and dated logof maintenance as performed in accordance with Section516.6.43 and Section 516.6.54 shall be available on thepremises 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 accordancewith Section 517.1.1 through Section 517.1.6. [NFPA96:14.1]

517.1.1 Natural Draft. Where solid-fuel cookingequipment is required by the manufacturer’s instructionsto have a natural draft, the vent shall be in accordancewith Section 517.4. [NFPA 96:14.1.1]

517.1.2 System Compliance. Where the solid-fuelcooking equipment has a self-contained top, is the onlyappliance to be vented in an isolated space (except for asingle water heater with its own separate vent), has a sepa-rate makeup-air system, and is provided with supply andreturn air (not supplied or returned from other spaces),the system shall be in accordance with Section 517.4 andSection 517.6. [NFPA 96:14.1.2]

517.1.3 Make-Up Air System. Where the solid-fuelcooking equipment is located in a space with other ventedequipment, all vented equipment shall have an exhaustsystem interlocked with a makeup-air system for thespace as per in accordance with Section 517.6. [NFPA96:14.1.3]

517.1.4 Natural Draft Ventilation Systems. Naturaldraft ventilation systems and power-exhausted ventilationsystems shall be in accordance comply with Section 517.3,Section 517.4, and Section 517.6. [NFPA 96:14.1.4]

517.1.5 Opening Requirements. Where a solid-fuelcooking appliance allows effluent to escape from the appli-ance opening, this opening shall be covered by a hood andan exhaust system that meets the requirements of Section517.3, Section 517.4, and Section 517.6. [NFPA 96:14.1.5]

517.1.6 Spark Arresters. Solid-fuel cooking opera-tions shall have spark arresters to minimize the passageof airborne sparks and embers into plenums and ducts.Where the solid-fuel cooking operation is not locatedunder a hood, a spark arrester shall be provided to mini-mize the passage of sparks and embers into flues andchimneys. [NFPA 96:14.1.6, 14.1.7]

517.2 Location of Appliances. 517.2.1 Access. EveryaAppliances shall be located with respect to building construc-tion and other equipment so as to permit access to the appli-ance. [NFPA 96:14.2.1]

517.2.21 Prohibited Location. Solid-fuel cookingappliances shall not be installed in confined spaces.[NFPA 96:14.2.2]

Exception: Solid-fuel cooking appliances listed for instal-lation in confined spaces such as alcoves shall be installedin accordance with the terms of the listing and the manu-facturer's installation instructions. [NFPA 96:14.2.3]

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517.2.32 Flammable Vapors. Solid-fuel cooking

appliances shall not be installed in any a location where

gasoline or any other flammable vapors or gases may be

are present. [NFPA 96:14.2.4]

517.3 Hoods for Solid-Fuel Cooking. 517.3.1 Sizeand Location. Hoods shall be sized and located in a manner

capable of capturing and containing all of the effluent

discharging from the appliances. The hood and its exhaust

system shall be in accordance with the provisions of the code.

[NFPA 96:14.3.1, 14.3.2]

517.3.21 Separation. Exhaust systems serving solid-

fuel cooking equipment, including gas or electrically

operated equipment, shall be separate from other exhaust

systems. [NFPA 96:14.3.3]

Exception: Cooking equipment not requiring automatic

fire-extinguishing equipment (in accordance with the

provisions of Section 5103.0) shall be permitted to be

installed under a common hood with solid-fuel cooking

equipment that is served by a duct system separate from

all other exhaust systems. [NFPA 96:14.3.5]

517.4 Exhaust Systems for Solid-Fuel Cooking.Where a hood is not required, in buildings where the duct

system is does not exceed three stories or less in height, a duct

complying with Section 510.0 shall be provided. [NFPA

96:14.4]

517.4.1 Hood. Where a hood is used in buildings where

the duct system is does not exceed three stories or less in

height, the duct system shall be in accordance with the

Section 510.0. [NFPA 96:14.4.1]

517.4.2 Four Stories Buildings. A listed or approved

grease duct system shall be provided for solid-fuel

cooking exhaust systems that are exceed four stories in

height or greater. [NFPA 96:14.4.2]

517.4.3 Prohibition. Wall terminations of solid-fuel

exhaust systems shall be prohibited. [NFPA 96:14.4.4]

517.5 Grease Removal Devices for Solid-FuelCooking. Grease removal devices shall be constructed of

steel or stainless steel or be approved for solid-fuel cooking.

[NFPA 96:14.5.1]

517.5.1 Spark Arrester Devices. Where airborne

sparks and embers can be generated by the solid-fuel

cooking operation, spark arrester devices shall be used

prior to the grease removal device to minimize the

entrance of these sparks and embers into the grease

removal device and into the hood and duct system.

[NFPA 96:14.5.2]

517.5.2 Filters. Filters shall be not less than 4 feet (1.2

1219 mm) above the appliance cooking surface. [NFPA

96:14.5.3]

517.6 Air Movement for Solid-Fuel Cooking. Exhaust

system requirements shall comply with the provisions of the

code for hooded operation or shall be installed in accordance

with the manufacturer's recommendation installation instruc-

tions for unhooded applications. [NFPA 96:14.6.1]

517.6.1 Replacement Air. A replacement or makeup-air system shall be provided to ensure a positive supplyof replacement air at all times during cooking operations.[NFPA 96:14.6.2]

517.6.2 Operation. Makeup-air systems serving solid-fuel cooking operations shall be interlocked with theexhaust-air system and powered, where necessary, toprevent the space from attaining a negative pressure whilethe solid-fuel appliance is in operation. [NFPA 96:14.6.3]

517.7 Fire-Extinguishing Equipment for Solid-FuelCooking. 517.7.1 Solid Fuel Burning Cooking Appli-ances. Approved fire-extinguishing equipment shall beprovided to protect all solid-fuel-burning cooking appliancesthat might be a source of ignition of grease in the hood, greaseremoval device, or duct.

Exception: Where acceptable to the Authority Having Juris-diction, solid-fuel-burning cooking appliances constructed ofsolid masonry or reinforced portland or refractory cementconcrete and vented in accordance with NFPA 211, Chapter3 and Chapter 4, shall not require fixed automatic fire-extin-guishing equipment. [NFPA 96:14.7.2]

517.7.21 Grease Removal Devices, Hoods, andDuct Systems. Approved fire-extinguishing equipmentshall be provided for the protection of grease removaldevices, hoods, and duct systems. [NFPA 96:14.7.3]

Exception: Where acceptable to the Authority HavingJurisdiction, solid-fuel-burning cooking appliancesconstructed of solid masonry or reinforced portland orrefractory cement concrete and vented in accordancewith NFPA 211, Chapter 3 and Chapter 4, shall notrequire automatic fire-extinguishing equipment for theprotection of grease removal devices, hoods, and ductsystems. [NFPA 96:14.7.4]

517.7.32 Standard. Approved fire-extinguishingequipment for solid-fuel-burning cooking appliances,where required, shall be in accordance with NFPA 211and shall be comprised of water-based agents. [NFPA96:14.7.5]

517.7.43 Rating and Design. Fire-extinguishingequipment shall be rated and designed to extinguish solid-fuel cooking fires, in accordance with the manufacturer'srecommendations instructions. The fire-extinguishingequipment shall be of sufficient size to totally extinguishfire in the entire hazard area and prevent reignition of thefuel. [NFPA 96:14.7.6, 14.7.7]

517.7.54 Listing/Class. Solid-fuel appliances(whether or not under a hood) with fireboxes of 5 cubicfeet (0.14 m3) volume or less shall at least have a listed2-A rated water-type fire extinguisher or a 1.6 gallon (6L) wet chemical fire extinguisher listed for Class K firesin accordance with NFPA 10, in the immediate vicinity ofand shall be located not more than 20 feet (6096 mm)from the appliance. [NFPA 96:14.7.8]

517.7.65 Fixed Water Pipe System. Solid-fuel appli-ances with fireboxes exceeding 5 cubic feet (0.14 m3) shallbe provided with a fixed-water-pipe system with a hose in

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the kitchen capable of reaching the firebox. The hose shallbe equipped with an adjustable nozzle capable of producinga fine to medium spray or mist. The nozzle shall be of thetype that cannot produce a straight stream. The system shallhave an operating pressure of not less than 40 psi (275.8276 kPa) and shall provide not less than 5 gallons perminute (gal/min) (0.32 L⁄S). [NFPA 96:14.7.9.1 - 14.7.9.2]

517.7.76 Fuel Storage. Fire suppression for fFuelstorage areas shall be in accordance with Section 517.8.[NFPA 96:14.7.10] be provided with a sprinkler systemthat is installed in accordance with NFPA 13.

517.7.87 Auxiliary Fuel. In addition to the require-ments of Section 517.7.54 or through Section 517.7.6,where a solid-fuel cooking appliance is also providedwith auxiliary electric, gas, oil, or other fuel for ignitionor supplemental heat and the appliance is also served bya portion of a fire-extinguishing system complying inaccordance with Section 513.0, such auxiliary fuel shallbe shut off upon actuation of the fire-extinguishingsystem. [NFPA 96:14.7.11]

517.8 Other Safety Requirements. 517.8.1 Listed.Metal-fabricated solid-fuel cooking appliances shall be listedfor the application where produced in practical quantities orshall be approved by the Authority Having Jurisdiction.Where listed, they shall be installed in accordance with theterms of their listings and with the applicable requirementsof this standard.

517.8.21 Site-Built Solid Fuel Cooling Appli-ances. Site-built solid-fuel cooking appliances shall besubmitted for approval to the Authority Having Jurisdic-tion before being considered for installation. Units shallbe installed, operated, and maintained in accordance withthe approved terms of the manufacturer's instructions andany additional requirements set forth by in accordancewith the Authority Having Jurisdiction.

517.8.32 Additional Devices. Except for the sparkarrester required in Section 517.1.6, there shall be noadditional devices of any type in a portion of the appli-ance, flue pipe, and chimney of a natural draft solid-fueloperation.

517.8.43 Prohibition. No solid-fuel cooking device ofany type shall be permitted for deep-fat frying involvingmore than 1 quart of liquid shortening, nor shall anysolid-fuel cooking device be permitted within 3 feet (0.92m 914 mm) of a deep-fat frying unit.

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