FAN ENGINEERING Information and Recommendations for the Engineer FE-3400 NFPA - 96 Standard for Ventilation Control and Fire Protection of Commercial Cooking Operations Introduction This Engineering Data letter is a summary of the major This standard is intended to be applied as a whole. points covered by the NFPA 96 standard and is not to be This standard cannot provide safe design and operation construed as a reprint of the standard. All the information if parts of it are not enforced or are arbitrarily deleted contained in the standard and exceptions to the standard in any applications. The authority having jurisdiction may not be fully covered in this summary. It will give (AHJ) shall determine compliance with this standard and you an overall view on what is required by this standard. authorize any deviations from it in all applications. Cooking equipment that produces smoke or grease- laden vapors shall be equipped with an exhaust system Origin and Development that complies with all the equipment and performance The NFPA Committee on Blower and Exhaust Systems requirements of this standard. All such equipment first considered the subject of the ventilation of restaurant and performance also needs to be maintained per cooking equipment. The committee developed material the requirements of this standard during all periods of on the ventilation of restaurant cooking equipment and operation. Specifically, the cooking equipment, hoods, included it in NFPA 91, Standard for the Installation of ducts, fans, fire suppression systems and special grease Blower and Exhaust Systems for Dust, Stock and Vapor collection or energy control equipment are to be kept in Removal or Conveying. In 1946 the Association adopted good working condition. this and revisions were adopted in 1947 and 1949. Airflows throughout all components of the system When the NFPA Committee on Chimneys and Heating must be maintained at intervals necessary to keep the Equipment was organized in 1955, the material on operating conditions of the equipment at the proper ventilation of restaurant cooking equipment in NFPA 91 levels. All interior surfaces of the exhaust system shall was assigned to this new committee with the suggestion be reasonably accessible for cleaning and inspection that it be revised and published as a separate standard. purposes. Over the years this new Committee made several Except where enclosures are required, hoods, grease revisions that were adopted by the Association through removal devices, exhaust fans, and ducts shall have a 1984 and in recent years the standard was published as clearance of at least 18 inches to combustible material, NFPA 96. 3 inches to limited combustible material and 0 inches to The Correlating Committee on Chimneys and Other non-combustible material. (See Fig. 1a - 1e.) This is only Heat and Vapor Removal Equipment was discharged by a guideline and there are several exceptions to these. the Standards Council in 1986. The Technical Committee Ultimately, the authority having jurisdiction (AHJ) has the that prepared the 1987 edition became known as the final say in the acceptance or rejection of the installation. Technical Committee on Venting Systems for Cooking In the event of a fire within the exhaust system, the Appliances. In the 1994 edition, the Committee changed system must be inspected by qualified personnel and the name of the standard from Standard for the Installation approved by the AHJ to determine whether the system of Equipment for the Removal of Smoke and Grease- is structurally sound, capable of maintaining their fire Laden Vapors from Commercial Cooking Equipment to the protection function, and suitable for continued operation. standard as it is known today. Clearances can be reduced by the installation of field applied or factory built grease duct enclosures. These must demonstrate that they provide sufficient mechanical General and structural integrity, resiliency and stability when subjected to expected building environmental conditions, NFPA 96 provides the minimum fire safety requirements duct movement under general operating, and fire related to the design, installation, operation, inspection, conditions. and maintenance of all public and private cooking A drawing of the exhaust system installation along operations except for single family residential usage. The with a copy of operating instructions for subassemblies requirements include, but are not limited to, all manner and components used in the exhaust system, including of cooking equipment, exhaust hoods, grease removal electrical schematics, shall be available on the premises. devices, exhaust ductwork, exhaust fans, dampers, fire extinguishing equipment and all other components or systems that are involved in the capture, containment and control of grease-laden cooking residue. The provisions of this standard are considered necessary to provide a reasonable level of protection from loss of life and property from fire and explosion. Figure 1a. Typical section view for building with two stories Figure 1d. Typical section view for one-story building with- or more with fire-rated floor-ceiling assembly out fire-rated roof-ceiling assembly Hinged, upblast Hinged, upblast exhaust fan 10 ft. exhaust fan 10 ft. Not less than 1-hr. Weather-protected 40 in. fire resistance for opening building less than Roof 18 in. 40 in. 4 stories in height - Not less than 18 in. clearance to combustibles Roof 18 in. - Not less than 6 in. to Not less than 2-hr. Access panel Opening in limited-combustibles or fire resistance for enclosure noncombustibles building 4 stories Second Grease duct or more in height story Continuous Ceiling Fire-rated floor-ceiling assembly enclosure Grease duct - 0 in. clearance to noncombustibles - 0 in. clearance to noncombustibles - 0 in. clearance to - 3 in. to clearance to limited-combustibles - 3 in. to clearance to limited-combustibles noncombustibles - 0 in. clearance to noncombustibles - 18 in. clearance to combustibles, - 18 in. clearance to combustibles, unless - 3 in. to clearance unless protected in accordance - 3 in. to clearance to limited-combustibles protected in accordance with to limited-combustibles with Exception No. 2 or 3 - 18 in. clearance to combustibles, unless Exception No. 2 or 3 - 18 in. clearance to Exhaust hood protected in accordance with combustibles, unless Exception No. 2 or 3 Exhaust hood protected in accordance with Exception No. 2 or 3 Sealed around the duct at this point, because of fire- rated floor-ceiling assembly Figure 1e. Detail drawings showing hoods penetrating ceilings Figure 1b. Typical section view for one-story building with fire-rated roof-ceiling assembly Second story Discharge Fire-rated Continuous enclosure Grease duct 10 ft. Exhaust fan floor-ceiling assembly Access panel Access panel 40 in. Weather-protected Sealed around hood with opening noncombustible material Sealed around the duct Roof at this point, because of fire-rated floor-ceiling assembly - 0 in. clearance to noncombustibles Fire-rated floor-ceiling assembly 1-hr. rated continuous enclosure - 3 in. to clearance to limited-combustibles Grease duct Exhaust - 18 in. clearance to combustibles, hood Sealed around the duct at unless protected in accordance this point, because of fire- with Exception No. 2 or 3 rated roof-ceiling assembly Typical Section View For building with two stories or more with fire-rated floor-ceiling assembly Exhaust hood Continuous enclosure Grease duct - 0 in. clearance to Second story Note: Clearance notes in Figure 1A also apply to this drawing. noncombustibles Fire-rated floor - 3 in. to clearance to limited-combustibles - 18 in. clearance to combustibles, unless protected in accordance with Exception No. 2 or 3 Sealed at this point, Figure 1c. Typical section view for building with two stories because of fire-rated floor or more with non-fire-rated ceiling and fire-rated floor Non fire-rated ceiling Discharge Exhaust fan Sealed around hood 10 ft. with noncombustible Exhaust Access panel material hood Access panel 40 in. Weather-protected opening Typical Section View Roof For building with two stories or more with non-fire-rated ceiling and fire-rated floor Not less than 1-hr. fire resistance for building less than 4 stories in height Opening in enclosure Not less than 2-hr. fire resistance for building 4 stories or more in height The hood size must of sufficient size and configured Fire-rated floor to capture and remove the grease-laden vapors. All Second story Non fire-rated ceiling seams, joints and penetrations of the hood must have Sealed around the duct Grease duct a liquidtight continuous external weld on the lower at this point, because of fire-rated floor outermost perimeter. Exhaust hood assemblies with integrated supply air plenums shall follow the same Exhaust hood construction requirements. A fire-actuated damper shall be installed in the supply air plenum at each point where a supply air duct inlet or Note: Clearance notes in Figure 1A also apply to this drawing. supply air outlet penetrates the continuously welded shell. The actuation device shall have a maximum temperature rating of 286o F. Supply air plenums that discharge air Hoods from the face rather than from the bottom or into the The hood or primary collection means designed for exhaust hood and are isolated from the hood do not collecting the cooking vapors and residues must be require a fire actuated damper. constructed of and be supported by steel or stainless All insulation materials, other than electrical insulation, steel of a certain minimum thickness. Other approved must have a flame-spread rating of 25 or less in materials of equivalent strength and fire and corrosion accordance with UL 723, Standard for Test for Surface resistance may also be used. Burning Characteristics of Building Materials. 2 FAN ENGINEERING – FE-3400 Listed hood assemblies shall be installed in accordance Figure 2. Telescoping and Bell-Type with the terms of their listing and manufacturer’s Duct Connections instructions. Telescoping Duct Joint Grease Removal Devices in Hoods Exhaust duct Listed grease filters, baffles, and other approved grease Inside Section I.D.