Capital Hood Cleaning


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NFPA 96 - Selected

Chapter 4 General Requirements

4.1 General.

4.1.1 Cooking equipment used in processes producing smoke or grease-laden vapors shall be equipped with an exhaust system that complies with all the equipment and performance requirements of this standard.

4.1.2 All such equipment and its performance shall be maintained in accordance with the requirements of this standard during all periods of operation of the cooking equipment.

4.1.3 The following equipment shall be kept in good working condition:
(1) Cooking equipment
(2) Hoods
(3) Ducts (if applicable)
(4) Fans
(5) Fire-extinguishing systems
(6) Special effluent or energy control equipment

4.1.4 All airflows shall be maintained.

4.1.5 Maintenance and repairs shall be performed on all components at intervals necessary to maintain these conditions.

4.1.6* All solid fuel cooking equipment shall comply with the requirements of Chapter 14.

4.1.7 Multiple tenancy applications shall require the concerted cooperation of design, installation, operation, and maintenance responsibilities by tenants and by the building owner.

4.1.8 All interior surfaces of the exhaust system shall be accessible for cleaning and inspection purposes.

4.1.9* Cooking equipment used in fixed, mobile, or temporary concessions, such as trucks, buses, trailers, pavilions, tents, or any form of roofed enclosure, shall comply with this standard unless all or part of the installation is exempted by the authority having jurisdiction.

4.2* Clearance.

4.2.1 Where enclosures are not required, hoods, grease removal devices, exhaust fans, and ducts shall have a clearance of at least 457 mm (18 in.) to combustible material, 76 mm (3 in.) to limited-combustible material, and 0 mm (0 in.) to noncombustible material.

4.2.2 Where a hood, duct, or grease removal device is listed for clearances less than those required in 4.2.1 the listing requirements shall be permitted.

4.2.3 Clearance Reduction.

4.2.3.1 Where a clearance reduction system consisting of 0.33 mm (0.013 in.) (28-gauge) sheet metal spaced out 25 mm (1 in.) on noncombustible spacers is provided, there shall be a minimum of 229 mm (9 in.) clearance to combustible material.

4.2.3.2 Where a clearance reduction system consisting of 0.69 mm (0.027 in.) (22-gauge) sheet metal on 25 mm (1 in.) mineral wool bats or ceramic fiber blanket reinforced with wire mesh or equivalent spaced out 25 mm (1 in.) on noncombustible spacers is provided, there shall be a minimum of 76 mm (3 in.) clearance to combustible material.

4.2.3.3 Zero clearance to limited-combustible materials shall be permitted where protected by metal lath and plaster, ceramic tile, quarry tile, other noncombustible materials or assembly of noncombustible materials, or materials and products that are listed for the purpose of reducing clearance.

4.2.4 Clearance Integrity.

4.2.4.1 In the event of damage, the material or product shall be repaired and restored to meet its intended listing or clearance requirements and shall be acceptable to the authority having jurisdiction.

4.2.4.2* In the event of a fire within a kitchen exhaust system, the duct and its enclosure (rated shaft, factory-built grease duct enclosure, or field-applied grease duct enclosure) shall be inspected by qualified personnel to determine whether the duct and protection method are structurally sound, capable of maintaining their fire protection function, and in compliance with this standard for continued operation.

4.2.4.3 Protection shall be provided on the wall from the bottom of the hood to the floor, or to the top of the noncombustible material extending to the floor, to the same level as required in 4.2.1.

4.2.4.4 The protection methods for ducts to reduce clearance shall be applied to the combustible or limited-combustible construction, not to the duct itself.

4.3 Field-Applied and Factory-Built Grease Duct Enclosures.

4.3.1 Field-applied grease duct enclosures and factory-built grease duct enclosures shall be installed in accordance with the manufacturers' instructions and the listing requirements.

4.3.2 Field-applied grease duct enclosures and factory-built grease duct enclosures shall demonstrate that they provide mechanical and structural integrity, resiliency, and stability when subjected to expected building environmental conditions, duct movement under general operating conditions, and duct movement due to fire conditions.

4.3.3 The specifications of material, gauge, and construction of the duct used in the testing and listing of field-applied grease duct enclosures and factory-built grease duct enclosures shall be included as minimum requirements in their listing and installation documentation.

4.3.4 Clearance Options for Field-Applied and Factory-Built Grease Duct Enclosures. The following clearance options for which field-applied grease duct enclosures and factory-built grease duct enclosures have been successfully evaluated shall be clearly identified in their listing and installation documentation and on their label:
(1) Open combustible clearance at manufacturer's requested dimensions
(2) Closed combustible clearance at manufacturer's requested dimensions, with or without specified ventilation
(3) Rated shaft clearance at manufacturer's requested dimensions, with or without specified ventilation

4.4 Building and Structural Duct Contact.

4.4.1 A duct shall be permitted to contact noncombustible floors, interior walls, and other noncombustible structures or supports, but it shall not be in contact for more than 50 percent of its surface area per each lineal foot of contact length.

4.4.2 Where duct contact must exceed the requirements of

4.4.1, the duct shall be protected from corrosion.

4.4.3 Where the duct is protected with a material or product listed for the purpose of reducing clearance to zero, the duct shall be permitted to exceed the contact limits of 4.4.1 without additional corrosion protection.

4.5 Duct Clearances to Enclosures. Clearances between the duct and interior surfaces of enclosures shall meet the requirements of Section 4.2.

4.6 Drawings. A drawing(s) of the exhaust system installation along with a copy of operating instructions for subassemblies and components used in the exhaust system, including electrical schematics, shall be kept on the premises.

4.7 Authority Having Jurisdiction Notification. If required by the authority having jurisdiction, notification in writing shall be given of any alteration, replacement, or relocation of any exhaust or extinguishing system or part thereof or cooking equipment.

 

Chapter 7 Exhaust Duct Systems

7.1 General.

7.1.1 Ducts shall not pass through fire walls.

7.1.2* All ducts shall lead directly to the exterior of the building, so as not to unduly increase any fire hazard.

7.1.3 Duct systems shall not be interconnected with any other building ventilation or exhaust system.

7.1.4 All ducts shall be installed without forming dips or traps that might collect residues. In manifold (common duct) systems, the lowest end of the main duct shall be connected flush on the bottom with the branch duct.

7.1.5 Openings required for accessibility shall comply with Section 7.3.

7.1.6 A sign shall be placed on all access panels stating the following: ACCESS PANEL - DO NOT OBSTRUCT

7.1.7 Listed grease ducts shall be installed in accordance with the terms of the listing and the manufacturers' instructions.

7.2 Clearance. Clearance between ducts and combustible materials shall be provided in accordance with the requirements of Section 4.2.

7.3 Openings.

7.3.1 Openings shall be provided at the sides or at the top of the duct, whichever is more accessible, and at changes of direction.

7.3.2 Openings shall be protected by approved access constructed and installed in accordance with the requirements of

7.4.4.

7.3.3 Openings shall not be required in portions of the duct that are accessible from the duct entry or discharge.

7.3.4 For hoods with dampers in the exhaust or supply collar, an access panel for cleaning and inspection shall be provided in the duct or the hood within 457 mm (18 in.) of the damper.

7.3.5 For common exhaust duct systems, access panel openings shall be provided for installation and servicing of the fire- extinguishing system.

7.3.6 Access panel opening shall not be required in portions of the common exhaust duct or branch duct that are accessible from the branch duct connection to the exhaust hood.

7.3.7 Exhaust fans with ductwork connected to both sides shall have access for cleaning and inspection within 0.92 m

(3 ft) of each side of the fan.

7.4 Openings in Ducts. All openings shall comply with the requirements of Section 7.4.

7.4.1 Horizontal Ducts.

7.4.1.1 Horizontal ducting support systems for nonlisted grease duct systems 24 in. and larger than 609 mm in any cross-sectional dimension shall be designed for the weight of the ductwork plus 363 kg (800 lbs) at any point in the duct systems.

7.4.1.2 On nonlisted ductwork, the edge of the opening shall be not less than 38.1 mm (1 1 ? 2 in.) from all outside edges of the duct or welded seams.

7.4.2 Vertical Ducts.

7.4.2.1 On vertical ductwork where personnel entry is possible, access shall be provided at the top of the vertical riser to accommodate descent.

7.4.2.2 Where personnel entry is not possible, adequate access for cleaning shall be provided on each floor.

7.4.2.3 On nonlisted ductwork, the edge of the opening shall be not less than 38.1 mm (1 1 ? 2 in.) from all outside edges of the duct or welded seams.

7.4.3 Access Panels.

7.4.3.1 Access panels shall be of the same material and thick- ness as the duct.

7.4.3.2 Access panels shall have a gasket or sealant that is rated for 815.6 º C (1500 º F) and shall be greasetight.

7.4.3.3 Fasteners, such as bolts, weld studs, latches, or wing nuts, used to secure the access panels shall be carbon steel or stainless steel and shall not penetrate duct walls.

7.4.3.4 Listed grease duct access door assemblies (access panels) shall be installed in accordance with the terms of the listing and the manufacturers' instructions.

7.4.4 Protection of Openings.

7.4.4.1 Openings for installation, servicing, and inspection of listed fire protection system devices and for duct cleaning shall be provided in ducts and enclosures and shall conform to the requirements of Section 7.3 and 7.7.4. 96 - 10 VENTILATION CONTROL AND FIRE PROTECTION OF COMMERCIAL COOKING OPERATIONS 2001 Edition

7.4.4.2 Enclosure openings required to reach access panels in the ductwork shall be large enough for the removal of the access panel.

7.5 Other Grease Ducts. Other grease ducts shall comply with the requirements of this section.

7.5.1* Materials. Ducts shall be constructed of and supported by carbon steel not less than 1.37 mm (0.054 in.) (No. 16 MSG) in thickness or stainless steel not less than 1.09 mm (0.043 in.) (No. 18 MSG) in thickness.

7.5.2 Installation.

7.5.2.1 All seams, joints, penetrations, and duct-to-hood collar connections shall have a liquidtight continuous external weld.

7.5.2.2 Duct-to-hood collar connections as shown in Figure 7.5.2.2 shall not require a liquidtight continuous external weld.

7.5.2.3 Penetrations shall be permitted to be sealed by other listed devices that are tested to be greasetight and are evaluated under the same conditions of fire severity as the hood or enclosure of listed grease extractors and whose presence does not detract from the hood's or duct's structural integrity.

7.5.2.4 Internal welding shall be permitted, provided the joint is formed or ground smooth and is readily accessible for inspection.

7.5.3 Penetrations shall be sealed with listed devices in accordance with the requirements of 4.2.3.3.

7.5.4 Devices that require penetration of the ductwork, such as pipe and conduit penetration fittings and fasteners, shall be listed in accordance with UL 1978, Standard for Safety for Grease Ducts.

7.5.5 Duct Connections.

7.5.5.1 Acceptable duct-to-duct connection shall be as follows:

(1) Telescoping joint as shown in Figure 7.5.5.1(a)

(2) Bell type joint as shown in Figure 7.5.5.1(b)

(3) Flange edge weld as shown in Figure 7.5.5.1(c)

(4) Flange filled weld as shown in Figure 7.5.5.1(d)

7.5.5.2 Butt welded connections shall not be permitted.

7.5.5.3 For telescoping and bell type connections, the inside duct section shall always be uphill of the outside duct section. Square, rectangular, or round in shape Continuous perimeter weld Joint with (815.6 ° C) 1500 ° F rated gasket or sealant Detail of sealed hood - duct joint Weld studs or bolts 6.4-mm ( ¹?? -in.) steel (min) O.D. of duct 3.2 mm ( ¹?? in.) less than I.D. of hood collar 25.4-mm × 25.4-mm

(1-in. × 1-in.) angle

(min), same gauge as duct

(min) o o o o o o o o o oo o o Perspective Hood top 6.4-mm ( ¹?? -in.) weld studs or bolts at each corner and 102-mm 4-in. (max) C L FIGURE 7.5.2.2 Permitted duct-to-hood collar connection. Inside section Outside section I.D. (mm) I.D. (mm) + 6.4 mm Weld around 16-gauge [1.6 mm ( ¹??? -in.)] black iron Telescoping duct joint 50.8 mm (max) [2 in. (max)] Exhaust duct Notes: 1. Duct size decreases (going upward) with each telescope. 2. Smaller (inside) duct section is always above or uphill (on sloped duct), to be self-draining into larger (outside) duct.

(max) FIGURE 7.5.5.1(a) Telescoping-type duct connection. Bell duct joint Weld around Female end Male end I.D. mm I.D. mm + 6.4 mm

(max) I.D. mm Exhaust duct 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. 16-gauge [1.6 mm ( ¹??? -in.)] black iron 50.8 mm (max) [2 in. (max)] FIGURE 7.5.5.1(b) Bell-type duct connection. 96 - 11 EXHAUST DUCT SYSTEMS 2001 Edition

7.5.5.4 For telescoping and bell type connections, the difference between inside dimensions of overlapping sections shall not exceed 6.4 mm ( 1 ? 4 in.).

7.5.5.5 For telescoping and bell type connections, the over- lap shall not exceed 50.8 mm (2 in.).

7.6 Exterior Installations.

7.6.1 The exterior portion of the ductwork shall be vertical wherever possible and shall be installed and supported on the exterior of a building.

7.6.2 Bolts, screws, rivets, and other mechanical fasteners shall not penetrate duct walls.

7.6.3 Clearance of any ducts shall comply with Section 4.2.

7.6.4 All ducts shall be protected on the exterior by paint or other suitable weather-protective coating.

7.6.5 Ducts constructed of stainless steel shall not be required to have additional paint or weather protective coatings.

7.6.6 Ductwork subject to corrosion shall have minimal con- tact with the building surface.

7.7 Interior Installations.

7.7.1 Duct Enclosures.

7.7.1.1 In all buildings where vertical fire barriers are penetrated, the ducts shall be enclosed in a continuous enclosure extending from the first penetrated fire barrier and any subsequent fire barriers or concealed spaces, to or through the exterior, so as to maintain the fire resistance rating of the highest fire barrier penetrated.

7.7.1.2 In all buildings more than one story in height, and in one-story buildings where the roof - ceiling assembly is required to have a fire resistance rating, the ducts shall be en- closed 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 building code provisions.

7.7.1.3 The enclosure shall be sealed around the duct at the point of penetration of the first fire-rated barrier after the hood in order to maintain the fire resistance rating of the enclosure.

7.7.1.4 The enclosure shall be vented to the exterior of the building through weather-protected openings.

7.7.1.5 The continuous enclosure provisions shall not be required where a field-applied grease duct enclosure or a factory-built grease duct enclosure

(see Section 4.3) is protected with a listed duct-through-penetration protection system equivalent to the fire resistance rating of the assembly being penetrated, and where the materials are installed in accordance with the conditions of the listing and the manufacturers ' instructions and are acceptable to the authority having jurisdiction.

7.7.2 Enclosure Fire Resistance Rating and Enclosure Clearance.

7.7.2.1 Fire Resistance Rating.

7.7.2.1.1 Buildings less than four stories in height shall have an enclosure with a fire resistance rating of not less than 1 hour.

7.7.2.1.2 Buildings four stories or more in height shall have enclosure with a fire resistance rating of not less than 2 hours.

7.7.2.2* Enclosure Clearance.

7.7.2.2.1 Clearance from the duct or the exhaust fan to the interior surface of enclosures of combustible construction shall be not less than 457.2 mm (18 in.).

7.7.2.2.2 Clearance from the duct to the interior surface of enclosures of noncombustible or limited-combustible construction shall be not less than 152.4 mm (6 in.).

7.7.2.2.3 Provisions for reducing clearances as described in Section 4.2 shall not be applicable to enclosures.

7.7.2.2.4 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 factory-built grease duct enclosures are installed in accordance with the conditions of the listing and manufacturers ' instructions and are acceptable to the authority having jurisdiction.

7.7.2.2.5 Field-applied grease duct enclosures and factory- built grease duct enclosures shall provide mechanical and structural integrity, resiliency, and stability when subjected to expected building environmental conditions, duct movement under general operating conditions, and duct movement as a result of interior and exterior fire conditions. FIGURE 7.5.5.1(c) Flanged with edge weld. FIGURE 7.5.5.1(d) Flanged with filled weld. 96 - 12 VENTILATION CONTROL AND FIRE PROTECTION OF COMMERCIAL COOKING OPERATIONS 2001 Edition

7.7.3 Protection of Coverings and Enclosure Materials.

7.7.3.1 Measures shall be taken to prevent physical damage to any covering or enclosure material.

7.7.3.2 Any 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.

7.7.3.3 In the event of a fire within a kitchen exhaust system, the duct, the enclosure, or the covering directly applied to the duct shall be inspected by qualified personnel to determine whether the duct, the enclosure, and the covering directly applied to the duct are structurally sound, capable of maintaining their fire protection functions, suitable for continued operation, and acceptable to the authority having jurisdiction.

7.7.3.4 Listed grease ducts shall be installed in accordance with the terms of the listing and the manufacturers ' instructions.

7.7.4 Enclosure Openings.

7.7.4.1 Where openings in the enclosure walls are provided, they shall be protected by listed fire doors of proper rating.

7.7.4.2 Fire doors shall be installed in accordance with NFPA 80, Standard for Fire Doors and Fire Windows .

7.7.4.3 Openings on other listed materials or products shall be clearly identified and labeled according to the terms of the listing and the manufacturers ' instructions and shall be acceptable to the authority having jurisdiction.

7.7.4.4 The fire door shall be readily accessible, aligned, and of sufficient size to allow access to the rated access panels on the ductwork.

7.7.5 Ducts with Enclosure(s).

7.7.5.1 Each duct system shall constitute an individual system serving only exhaust hoods in one fire zone on one floor.

7.7.5.2 Multiple ducts shall not be permitted in a single en- closure unless acceptable to the authority having jurisdiction.

7.8* Termination of Exhaust System.

7.8.1 The exhaust system shall terminate as follows:

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

(2) Through the roof, or to the roof from outside, as in 7.8.2, or through a wall, as in 7.8.3

7.8.2 Rooftop Terminations.

7.8.2.1 Rooftop terminations shall be arranged with or pro- vided with the following:

(1) A minimum of 3.05 m (10 ft) of horizontal clearance from the outlet to adjacent buildings, property lines and air intakes.

(2) A minimum of 1.5 m (5 ft) of horizontal clearance from the outlet (fan housing) to any combustible structure.

(3) A vertical separation of 0.92 m (3 ft) below any exhaust outlets for air intakes within 3.05 m (10 ft) of the exhaust outlet.

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

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

(6) Listed grease collection systems that meet the requirements of 7.8.2.1(4) and 7.8.2.1(5).

(7) A listed grease duct complying with Section 4.4, or with ductwork complying with Section 4.5.

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

(a) Where the fan attaches to the ductwork, the ductwork shall be a minimum of 0.46 m (18 in.) away from any roof surface as shown in Figure 7.8.2.1.

(b) The fan shall discharge a minimum of 1.02 m (40 in.) away from any roof surface as shown in Figure 7.8.2.1.

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

(a) The requirements of 7.8.2.1(3) and 8.1.3

(b) Its discharge or its extended duct discharge meets the requirements of 7.8.2.1(2). (See 8.1.3.)

7.8.2.2* Fans shall be provided with safe access and a work surface for inspection and cleaning.

7.8.3 Wall Terminations. Wall terminations shall be arranged with or provided with the following properties:

(1) Through a noncombustible wall with a minimum of 3.05 m

(10 ft) of clearance from the outlet to adjacent buildings, property lines, grade level, combustible construction, electrical equipment or lines, and the closest point of any air intake or operable door or window at or below the plane of the exhaust termination.

(2) The closest point of any air intake or operable door or window above the plane of the exhaust termination shall be a minimum of 3 m (10 ft) in distance, plus 0.076 m

(0.25 ft) for each 1 degree from horizontal, the angle of degree being measured from the center of the exhaust termination to the center of the air intake or operable door or window as indicated in Figure 7.8.3. Fresh air in Possible roof line 0.92 m (min) [3 ft (min)] Roof curb Exhaust blower Exhaust air Wind direction Outside air intake 1.02 m (min) [40 in. (min)] 0.46 m (min) [18 in. (min)] FIGURE 7.8.2.1 Upblast fan clearances. 96 - 13 EXHAUST DUCT SYSTEMS 2001 Edition

(3) A wall termination in a secured area shall be permitted to be at a lower height above grade if acceptable to the authority having jurisdiction.

(4) The exhaust flow directed perpendicularly outward from the wall face or upward.

(5) All the ductwork pitched to drain the grease back into the hood(s), or with a drain provided to bring the grease back into a container within the building or into a remote grease trap.

(6) A listed grease duct complying with Section 7.4, or other ducts complying with Section 7.5.

(7) An approved fan, provided it meets the requirements of 7.8.3(5) and 8.1.1 or 8.1.3.

7.8.4* Roof Top Terminations Through Combustible or Limited-Combustible Walls.

7.8.4.1 Ductwork that exits a building through a combustible or limited-combustible wall to terminate above the roof line shall have wall protection provided in accordance with Section 4.2.

7.8.4.2 Where the ductwork exits the building the opening shall be sealed and shall include a weather-protected vented opening.

7.8.4.3 Where the ductwork exits through a rated wall the penetration shall be protected in accordance with 4.4.1.

 

 

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