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Kitchen Exhaust Systems

Rev1
IssuedJun 18, 2026

Revision history

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1 Scope

NOTE This specification covers the design and specification of commercial kitchen exhaust ventilation systems serving food service operations, from the cooking-equipment capture zone through the rooftop or wall termination, together with the makeup air system that replaces the exhausted air. (1.1)
NOTE Equipment covered includes Type I grease-laden exhaust hoods (wall-canopy, single- and double-island, low-profile/proximity, back-shelf, and pass-over), Type II heat-and-steam hoods for non-greasy appliances, grease ducts and their access and clearance provisions, grease-rated exhaust fans and grease collection devices, makeup air units, and demand-controlled kitchen ventilation. (1.2)
NOTE The work under this standard includes the hood body and capture geometry, the grease duct from hood collar to fan, the exhaust fan and its rooftop termination, the grease collection devices, the makeup air unit and its delivery to the kitchen, and the energy-management controls integral to the exhaust and makeup air system. (1.3)
1.4 Equipment and installation shall comply with NFPA 96 for fire and life safety, the International Mechanical Code Chapter 5 for mechanical design, the applicable UL listings for hoods, ducts, and fans, and the adopted energy code for demand-controlled ventilation.
NOTE A commercial kitchen exhaust system is a fire-protection assembly first and an air-moving assembly second: grease-laden vapor condenses on every interior surface of the hood and duct, so capture geometry, duct material and slope, access for cleaning, and clearance to combustibles are governed by fire codes, not comfort criteria. (1.5)
NOTE The exhaust and makeup air sides are a single pressure-balanced system — exhaust without coordinated makeup air starves the hood of capture air, depressurizes the kitchen, and can backdraft flue-gas appliances in adjacent spaces, so the two are specified together. (1.6)

1.7 Scope Boundary

NOTE The boundary of work under this standard runs from the cooking-equipment capture zone, through the hood, grease duct, exhaust fan, and termination, and includes the makeup air unit and its supply path back into the kitchen. (1.7.1)
NOTE The wet-chemical fire suppression system, its nozzles, and its interlocks to the exhaust fan and fuel/electrical shutoff are covered by Kitchen Hood Fire Suppression and are excluded here. (1.7.2)
1.7.3 The hood geometry shall be coordinated with Kitchen Hood Fire Suppression to ensure nozzle placement is compatible with the hood configuration specified under this standard.
NOTE General HVAC supply and return ductwork outside the kitchen exhaust and makeup-air assembly is covered by Hvac Ductwork. (1.7.4)
NOTE General exhaust fans and fan selection for non-grease service are covered by Hvac Fans; only grease-rated exhaust fans are within this standard. (1.7.5)
NOTE Volume, fire, and combination fire/smoke dampers are covered by Louvers And Dampers; Type I grease ducts are exempt from dampers and shall contain none, but dampers in connected makeup air and general systems remain under that standard. (1.7.6)
NOTE Air balancing, capture-and-containment field verification, and commissioning of the completed system are covered by Testing Adjusting And Balancing. (1.7.7)
NOTE Residential range hoods, industrial process exhaust, and chemical fume exhaust are outside this standard entirely. (1.7.8)

2 Referenced Standards

2.1 Equipment, materials, and installation shall comply with the latest adopted edition of each of the following unless a specific edition is cited.
2.2 Where referenced standards, the adopted mechanical and energy codes, the manufacturer's listing, or the contract documents conflict, the more stringent requirement shall govern unless the Engineer of Record directs otherwise in writing.

2.3 Standards Table

Standard Title
NFPA 96 (2024) Standard for Ventilation Control and Fire Protection of Commercial Cooking Operations
IMC Chapter 5 (2021) International Mechanical Code — Exhaust Systems, Sections 505 through 509
ANSI/ASHRAE 154-2016 Ventilation for Commercial Cooking Operations
ANSI/ASHRAE/IES 90.1-2019 Energy Standard for Buildings Except Low-Rise Residential Buildings (Section 6.5.7.1, kitchen DCKV)
UL 710 Exhaust Hoods for Commercial Cooking Equipment
UL 705 Supplement SC Power Ventilators — Restaurant Exhaust (incorporates former UL 762)
UL 1978 Grease Ducts
ASTM E2336 Standard Test Methods for Fire Resistive Grease Duct Enclosure Systems
NSF/ANSI 2 Food Equipment
IBC Section 717.5.3 (2021) International Building Code — Grease Duct Damper Exemption
NOTE The exhaust fan listing standard is UL 705 Supplement SC; UL 762 was withdrawn and merged into Supplement SC, so submittals citing UL 762 alone shall be corrected to the current designation. (2.4)
NOTE NFPA publishes on a three-year cycle and the 2024 edition of NFPA 96 is the current cycle; verify the edition adopted by the authority having jurisdiction, as adoption typically lags publication. (2.5)

3 Submittals

3.1 Action Submittals

3.1.1 The Contractor shall submit the following action submittals for review before fabrication or ordering:
  • Product data for each hood, including model, listing (UL 710), dimensions, exhaust and supply collar sizes, and rated exhaust CFM
  • Cooking-equipment schedule cross-referenced to each hood, demonstrating that the equipment lineup matches the configuration under which the hood was listed
  • Shop drawings showing hood plan and elevation, capture overhang on all open sides, duct collar locations, and integral supply plenum arrangement
  • Grease duct shop drawings showing material and gauge, routing, slope, access-panel locations and sizes, and clearance or enclosure strategy to combustibles
  • Exhaust fan product data with UL 705 Supplement SC listing, fan curve at the scheduled operating point, motor data, and grease-tight hinged-housing detail
  • Makeup air unit product data, including heating source and capacity, supply temperature, delivery configuration, and airflow
  • DCKV product data showing sensor type, sensor-zone-to-equipment-zone mapping, control sequence, and variable-frequency-drive data where provided
  • Structural and vibration-isolation details for the exhaust fan at the roof curb
Action Submittalscheckbox
Hood product data and UL 710 listing
Cooking-equipment schedule cross-referenced to hood listing
Hood shop drawings (plan, elevation, overhang, collars)
Grease duct shop drawings (material, slope, access, clearance)
Exhaust fan product data and fan curve
Makeup air unit product data and capacity
DCKV sensor mapping and control sequence
Fan structural and vibration-isolation details

3.2 Informational Submittals

3.2.1 The Contractor shall submit the following informational submittals:
  • UL 710 listing test report or listing mark confirming the rated exhaust CFM for the installed equipment lineup
  • Welder qualifications and weld procedure for field-welded grease duct, or UL 1978 listing data for factory-built grease duct
  • Manufacturer's installation instructions for hoods, fans, makeup air units, and DCKV
  • Energy-code compliance documentation demonstrating the DCKV trigger evaluation under ASHRAE 90.1 Section 6.5.7.1 or the locally adopted energy code
Informational Submittalscheckbox
UL 710 listing report for installed equipment lineup
Welder qualifications / weld procedure or UL 1978 duct listing
Manufacturer installation instructions
Energy-code DCKV compliance documentation

3.3 Closeout Submittals

3.3.1 The Contractor shall submit the following closeout submittals:
  • Operation and maintenance manuals for hoods, fans, makeup air units, and DCKV controls
  • Cleaning-access record drawing marking every access panel location for the kitchen-cleaning contractor and the fire marshal
  • Air-balance report for exhaust and makeup air, coordinated with Testing Adjusting And Balancing
  • Warranty documents for hoods, fans, makeup air units, and controls
Closeout Submittalscheckbox
O&M manuals (hoods, fans, MAU, DCKV)
Cleaning-access record drawing
Exhaust and makeup air balance report
Warranty documents

4 Quality Assurance

4.1 Hoods shall be listed and labeled to UL 710 for the cooking-equipment duty served.
4.2 Exhaust fans in grease service shall be listed and labeled to UL 705 Supplement SC.
4.3 Factory-built grease duct, where used in lieu of field-welded duct, shall be listed and labeled to UL 1978.
NOTE Zero-clearance grease duct enclosure systems, where used in lieu of the prescriptive 18 in. clearance or a rated shaft, shall be tested and listed to ASTM E2336. (4.4)
NOTE Field welders for carbon-steel and stainless-steel grease duct shall be qualified to a recognized welding procedure, and welds shall be liquid-tight and externally visible for inspection. (4.5)
NOTE The UL 710 hood listing is specific to the cooking-equipment lineup tested; any change to the equipment schedule after listing voids the listed exhaust rate, and the hood shall be re-evaluated against the revised lineup before construction documents are issued. (4.6)
NOTE Where the hood is listed under UL 710, the listed exhaust rate established by the listing test report shall govern over the IMC prescriptive table per IMC Section 507.3.5. (4.7)

5 Environmental and Service Conditions

NOTE Hoods shall be classified by the cooking duty they serve, and the exhaust rate, capture velocity, and duct sizing shall follow from that classification. (5.1)
NOTE Cooking duty is classified as light, medium, heavy, or extra-heavy: light duty covers ovens, steam equipment, and pasta cookers; medium duty covers ranges, griddles, and fryers; heavy duty covers gas under-fired broilers; and extra-heavy duty covers solid-fuel cooking such as charcoal, wood, and mesquite. (5.2)
NOTE Type I hoods shall be provided over all cooking equipment that produces grease-laden vapors, and Type II hoods shall be provided over equipment that produces only heat, moisture, or products of combustion without grease. (5.3)
NOTE Makeup air shall maintain the kitchen at a slight negative pressure, on the order of −0.05 in. w.g. relative to adjacent occupied spaces, so that cooking odors and heat do not migrate into the dining room while the kitchen does not depressurize enough to backdraft fuel-fired appliances. (5.4)
NOTE In cold climates, makeup air shall be tempered so that untempered outdoor air does not chill staff at the cooking line or collapse the thermal plume the hood relies on for capture; energy-code limits on winter supply temperature shall be observed, with indirectly tempered makeup air permitted to be delivered as low as 60 °F under ASHRAE 90.1. (5.5)
Hood Cooking Duty Classificationselect
Light duty (ovens, steamers, pasta cookers)
Medium duty (ranges, griddles, fryers)
Heavy duty (gas under-fired broilers)
[object Object]
Hood Typeradio
Type I (grease-laden vapor)
Type II (heat and steam, non-greasy)
Climate Zone Makeup Air Temperingradio
Untempered (mild climate, light duty only)
Indirect-fired tempered
Direct-fired tempered
Heat-pump / DX tempered

6 Hood Construction and Geometry

6.1 Hood Body and Materials

6.1.1 The hood body shall be constructed of stainless steel or galvanized steel, with all exposed-to-view and grease-contact interior surfaces of stainless steel finished to NSF/ANSI 2 for cleanability.
6.1.2 Type I hood interior surfaces shall be liquid-tight and continuously welded so that condensed grease drains to the integral grease trough and gutter rather than seeping into seams.
NOTE Each Type I hood shall be furnished with listed grease filters or baffle extractors, removable for cleaning, that drain captured grease to the hood's grease cup. (6.1.3)
NOTE Each Type I hood shall be furnished with a continuous grease gutter and a removable grease cup at the low point of the hood. (6.1.4)
Hood Body Materialradio
Stainless steel, type 304
Stainless steel, type 430
Galvanized steel body with stainless front and ends
Hood Configurationselect
Wall-mounted canopy
Single-island canopy
Double-island canopy
Low-profile / proximity
Back-shelf
Pass-over

6.2 Capture Geometry

6.2.1 Wall-canopy hoods shall overhang the cooking surface by at least 6 in. on each open side per IMC Section 507.3.1.
6.2.2 Wall-canopy hoods shall be specified with a 12 in. overhang as the default for typical wall-canopy installations.
6.2.3 Island canopy hoods shall overhang the cooking surface on all open sides and shall be designed with the larger overhang and exhaust rate appropriate to their cross-draft exposure.
NOTE Island canopy hoods are exposed to cross-drafts on all sides, which increases the required capture area and exhaust rate compared with wall-canopy hoods. (6.2.4)
6.2.5 The hood shall be mounted so that the lower edge is no higher above the cooking surface than the listing and the duty permit, because raising the hood enlarges the capture area and increases the required exhaust rate.
NOTE The hood face shall maintain a capture velocity of at least 50 FPM for light-duty cooking and at least 75 FPM for heavy-duty and wok cooking per ASHRAE 154-2016. (6.2.6)
Hood Overhang Beyond Cooking Surface (Open Sides)range
in
624
Default: 12 in
Design Capture Velocity at Hood Facerange
FPM
50100
Default: 75 FPM
6.2.7 The mounting height of the hood lower edge above the finished floor is set by the cooking-equipment layout and ceiling height shown on the drawings. kitchen equipment elevation

6.3 Integral Supply Plenum

6.3.1 Where a short-circuit or front-face supply plenum is integral to the hood, it shall deliver makeup air at the hood face without disrupting the capture of grease-laden vapor into the exhaust collar.
6.3.2 Short-circuit makeup air introduced through an integral plenum shall be limited to the fraction the hood is listed to handle.
NOTE Short-circuit makeup air reduces the heating and cooling load on the makeup air unit by introducing a portion of replacement air directly at the hood; excessive short-circuit air beyond the listed fraction spills cooking effluent past the filters. (6.3.3)
Integral Supply Plenumradio
None (all makeup air from space or ceiling diffusers)
Front-face (short-circuit) supply plenum
Rear-discharge supply plenum

7 Exhaust Airflow

NOTE Type I wall-canopy hood exhaust rate shall be determined by the IMC Table 507.3.4 prescriptive rate per linear foot of hood for the applicable cooking duty, by the UL 710 listed rate, or by an ASHRAE 154 engineered calculation, whichever the design basis adopts. (7.1)
NOTE The IMC prescriptive rates for Type I wall-canopy hoods are 150 CFM per linear foot for light duty, 200 CFM per linear foot for medium duty, 300 CFM per linear foot for heavy duty, and 400 to 550 CFM per linear foot for extra-heavy duty; a typical restaurant griddle and range line falls in the 200 to 300 CFM per linear foot range. (7.2)
NOTE Type II hood exhaust rate shall be calculated at 0.70 CFM per square foot of hood face area per IMC Section 507.3.3, or sized at approximately 100 CFM per linear foot for typical heat-and-steam hoods. (7.3)
7.4 Where the hood is UL 710 listed, the listed exhaust rate shall be used and shall be confirmed against the installed cooking-equipment lineup before the exhaust rate is finalized.
Exhaust Rate Determination Methodradio
IMC Table 507.3.4 prescriptive (CFM per linear foot)
UL 710 listed rate
ASHRAE 154 engineered calculation
Type I Wall-Canopy Prescriptive Exhaust Raterange
CFM/lin ft
150550
Default: 250 CFM/lin ft
Type II Hood Exhaust Raterange
CFM/lin ft
75200
Default: 100 CFM/lin ft
7.4.1 The scheduled exhaust CFM for each hood is established on the mechanical schedule. kitchen hood schedule

8 Grease Duct

8.1 Duct Material and Construction

8.1.1 Grease duct shall be constructed of carbon steel not less than 16 gauge (0.055 in.) or stainless steel not less than 18 gauge (0.044 in.) per NFPA 96 §4.1, and the default for field-welded duct shall be 16-gauge carbon steel.
8.1.2 Galvanized steel shall not be used for grease duct.
8.1.3 Field-welded grease duct shall be continuously welded liquid-tight on all seams and joints, with no internal obstruction, ledge, or trap that could collect grease.
8.1.4 Factory-built grease duct, where used, shall be a UL 1978 listed assembly installed per its listing.
Grease Duct Constructionradio
Field-welded carbon steel, 16 gauge
Field-welded stainless steel, 18 gauge
UL 1978 listed factory-built assembly
NOTE Galvanized steel is explicitly prohibited for grease duct because the zinc coating fails at grease-fire temperatures and emits hazardous fume; this is a frequent specification error and an automatic AHJ rejection. (8.1.5)

8.2 Slope and Drainage

8.2.1 Horizontal grease duct runs shall slope not less than 1/4 in. per foot (2%) toward the hood or toward an approved grease reservoir per IMC Section 506.3.2 and NFPA 96 §4.3.
NOTE A flat or reverse-sloped duct section pools condensed grease and creates a fire hazard, so the slope shall be verified in the structural and BIM coordination of every horizontal run. (8.2.2)
Horizontal Duct Slope Toward Hood / Reservoirrange
in/ft
0.251
Default: 0.25 in/ft

8.3 Velocity

8.3.1 Grease duct shall be sized for an air velocity of not less than 500 FPM per IMC Section 506.3.3.
8.3.2 Grease duct shall be designed for a velocity in the range of 1,500 to 2,500 FPM to keep grease entrained and moving rather than settling.
8.3.3 The default design velocity shall be approximately 1,800 FPM, which keeps grease in transport without imposing excessive static pressure on the exhaust fan.
Grease Duct Design Velocityrange
FPM
5002500
Default: 1800 FPM

8.4 Clearance and Enclosure

8.4.1 Grease duct shall maintain a clearance to combustible construction of not less than 18 in. per IMC Section 506.3.1 and NFPA 96 §4.2.1, reducible to 3 in. to noncombustible construction.
8.4.2 Where the 18 in. clearance cannot be maintained, the duct shall be enclosed in a fire-rated shaft or wrapped in an ASTM E2336 listed zero-clearance enclosure system installed per its listing.
NOTE Grease duct routed through occupied spaces without a rated shaft or a listed zero-clearance enclosure is a common permit-review rejection, so the enclosure strategy shall be resolved and shown on the drawings before submission. (8.4.3)
Duct Clearance / Enclosure Strategyradio
Open with 18 in. clearance to combustibles
3 in. clearance to noncombustible construction
Fire-rated shaft enclosure
ASTM E2336 listed zero-clearance enclosure wrap
NOTE Type I grease ducts shall not contain fire dampers or smoke dampers; they are exempt under IBC Section 717.5.3 and NFPA 96 §4.5, and a damper installed in a grease duct traps grease and creates a fire hazard. (8.4.4)

8.5 Access Panels

8.5.1 Cleaning access panels shall be provided at each change of direction and along straight runs at not more than 12 ft on center on horizontal runs and not more than 20 ft on center on vertical runs per NFPA 96 §12.2.
8.5.2 Access panels shall be not less than 20 in. × 20 in. where the duct dimension permits, sized so the full internal duct surface can be reached and cleaned.
NOTE Undersized or too-widely-spaced access panels prevent the duct from being cleaned to NFPA 96 §11 and are routinely rejected by fire marshals and health inspectors, so panel size and spacing shall be shown on the grease duct shop drawings. (8.5.3)
Access Panel Sizeselect
20 in. × 20 in.
12 in. × 12 in. (small duct, where 20 in. will not fit)
15 in. × 15 in.
Horizontal Access Panel Spacingrange
ft
612
Default: 12 ft
8.5.4 The routing of the grease duct from each hood collar to the exhaust fan is shown on the drawings. grease duct routing plan

9 Exhaust Fan and Termination

9.1 Fan Selection

9.1.1 The exhaust fan shall be listed and labeled to UL 705 Supplement SC for grease-laden exhaust service.
NOTE Specifying UL 762 alone for the exhaust fan generates an RFI, because UL 762 was withdrawn and merged into UL 705 Supplement SC; the current designation shall be used. (9.1.2)
NOTE Upblast roof-mounted fans, inline grease-tight fans, and grease-rated utility sets are each acceptable for grease service when listed to UL 705 Supplement SC; the upblast roof fan is the default for typical restaurant applications. (9.1.3)
NOTE Inline fans, where used, shall be a grease-tight housing listed for the service and shall be provided with a residue collection and drainage provision at the housing low point. (9.1.4)
Exhaust Fan Typeradio
Upblast roof-mounted (hinged for cleaning access)
Inline grease-tight (UL 705 Supp. SC)
Grease-rated utility set

9.2 Cleaning Access and Grease Collection

9.2.1 Upblast roof fans shall be furnished with a hinged grease-tight housing or a hinged curb so the fan can be lifted clear for duct and fan cleaning per NFPA 96 §7.1.
9.2.2 A grease collection device shall be provided at the base of each duct riser or at the fan to receive drained grease, and the collector shall not exceed 1 gal capacity before an automatic shutoff or alarm per NFPA 96 §7.2.
NOTE The fan housing and curb shall be sealed grease-tight so that condensed grease drains back into the duct and collector rather than onto the roof membrane. (9.2.3)
Rooftop Fan Cleaning Accessradio
Hinged fan housing
Hinged grease curb
Both hinged housing and hinged curb

9.3 Vibration Isolation

9.3.1 Roof-mounted exhaust fans shall be isolated from the roof structure with spring isolators or an inertia base, and a flexible connector shall be provided at the fan inlet, coordinated with Hvac Fans.
NOTE Upblast fans transmit running vibration directly into the roof deck and into the dining space below if hard-mounted, so isolation shall be specified rather than left to the installer. (9.3.2)

9.4 Termination

9.4.1 The rooftop exhaust termination shall discharge not less than 10 ft above the adjoining roof surface per NFPA 96 §7.8, subject to variation by the authority having jurisdiction.
9.4.2 The exhaust discharge shall be directed away from, and separated from, building air intakes and operable openings per IMC Section 501.3 so that grease-laden exhaust is not re-entrained into the building.
9.4.3 The exact location, height, and separation of the rooftop termination relative to intakes and adjacent construction are fixed on the roof plan. roof termination and intake separation plan
Rooftop Termination Height Above Roofrange
ft
1030
Default: 10 ft

10 Makeup Air

10.1 Quantity

10.1.1 Makeup air shall be provided whenever the exhaust rate exceeds 400 CFM per IMC Section 508.1.
10.1.2 Makeup air quantity shall be specified at 80% to 90% of the exhaust volume so that the kitchen is held at a slight negative pressure relative to adjacent spaces, with a default of 85%.
NOTE Mechanical makeup air shall not draw flue gases from water heaters, furnaces, or other fuel-fired appliances in adjacent spaces; the makeup air quantity shall be coordinated with the building pressurization so the kitchen does not backdraft those appliances. (10.1.3)
Makeup Air Quantity (Percent of Exhaust)range
%
80100
Default: 85 %

10.2 Delivery and Tempering

NOTE Makeup air shall be delivered by an integral hood supply plenum, by ceiling diffusers near the cooking line, or by a transfer-air path from conditioned adjacent space, sized so that delivery velocity does not disturb hood capture. (10.2.1)
NOTE The makeup air heating source shall be selected as direct-fired gas, indirect-fired gas, or heat-pump/DX, coordinated with the available fuel supply and the energy code, and the gas heating section shall be sized for the design winter heating load rather than for cooling capacity alone. (10.2.2)
NOTE Makeup air unit gas heating capacity shall be confirmed against the available gas service, because a large makeup air unit serving a large exhaust in a cold climate can demand more gas than the building service was sized to deliver; coordinate the gas load with the plumbing scope. (10.2.3)
Makeup Air Delivery Methodselect
Integral hood supply plenum
Ceiling diffusers near cooking line
Transfer air from conditioned adjacent space
Dedicated makeup air diffuser bank
Makeup Air Heating Sourceradio
Direct-fired gas
Indirect-fired gas
Heat-pump / DX
Untempered (mild climate, light duty)
Makeup Air Winter Supply Temperaturerange
°F
5575
Default: 65 °F

11 Demand-Controlled Kitchen Ventilation

NOTE DCKV shall be evaluated for every Type I hood under the adopted energy code; ASHRAE 90.1-2019 Section 6.5.7.1 requires DCKV for any single Type I hood with an exhaust rate of 5,000 CFM or greater, or where total kitchen exhaust is 15,000 CFM or greater. (11.1)
NOTE Where DCKV is required or elected, the system shall vary exhaust fan and makeup air fan speed through variable-frequency drives in response to optical and temperature sensors that detect cooking activity. (11.2)
NOTE DCKV sensors shall be zoned to the cooking-equipment layout so that the fan reduces speed only when the equipment under a given sensor zone is idle; sensors placed over a cold zone that does not track the active fryers or broilers will not modulate correctly. (11.3)
11.4 The DCKV submittal shall show the sensor zones overlaid on the cooking-equipment layout so that sensor-to-equipment correspondence can be verified before installation.
NOTE At reduced cooking load the exhaust and makeup air fans shall turn down together so that the design pressure relationship between the kitchen and adjacent spaces is maintained across the operating range. (11.5)
Kitchen Ventilation Controlradio
Fixed-speed (on/off)
DCKV with VFD and optical + temperature sensors
DCKV Turndown Floor (Minimum Fan Speed)range
%
3060
Default: 40 %

12 Testing

NOTE Field testing and balancing of the completed kitchen exhaust and makeup air system shall be performed under Testing Adjusting And Balancing, and this section establishes the acceptance criteria to be verified. (12.1)
12.2 Measured exhaust airflow at each hood shall be within ±10% of the scheduled value.
12.3 Measured makeup air shall be confirmed to hold the kitchen at the design pressure relationship, on the order of −0.05 in. w.g. relative to adjacent occupied spaces.
NOTE The hood shall be verified to capture and contain cooking effluent across the cooking line with no visible spillage at the design exhaust rate, per the ASHRAE 154 capture-and-containment criterion. (12.4)
12.5 Grease duct welds and access-panel frames shall be verified liquid-tight, and the duct slope shall be verified continuous to the hood or reservoir on all horizontal runs.
12.6 DCKV operation shall be verified by demonstrating that fan speed reduces under idle conditions and returns to full speed under active cooking in each sensor zone.

13 Installation

NOTE Hoods, ducts, fans, and makeup air units shall be installed in accordance with their listings and the manufacturers' instructions, and the grease exhaust system shall be installed independent of any other building exhaust or ventilation system per IMC Section 506.3. (13.1)
13.2 Each Type I grease exhaust system shall serve only the hoods of a single cooking operation and shall not be interconnected with general building exhaust.
13.3 Grease duct shall be installed with the full required clearance or listed enclosure maintained continuously through every penetration, framing pocket, and concealed space, with no point of reduced clearance.
NOTE The exhaust fan, makeup air unit, and DCKV controls shall be interlocked so that the makeup air and exhaust start and stop together and the makeup air fan cannot run without the exhaust fan. (13.4)
NOTE The exhaust fan and fuel/electrical shutoff interlocks required by the fire suppression system shall be coordinated with Kitchen Hood Fire Suppression so that actuation of the suppression system shuts down the exhaust fan and fuel as required by NFPA 96. (13.5)
13.6 Penetrations of fire-rated assemblies by grease duct shall be firestopped with a system listed for grease duct, maintaining the rating of the assembly and the required duct clearance or enclosure.

14 Delivery, Storage, and Handling

14.1 Hoods and makeup air units shall be delivered with protective film on stainless surfaces and shall be stored indoors and protected from weather, dust, and physical damage until installation.
14.2 Grease duct material and listed factory-built duct shall be stored off the ground and kept dry and free of debris and oil so that welds and listed joints can be made clean.
NOTE Stainless-steel surfaces shall be protected from contact with carbon steel during storage and handling to prevent ferrous contamination and subsequent rust staining of the finish. (14.3)

15 Warranty

15.1 The Contractor shall warrant the kitchen exhaust system against defects in materials and workmanship for not less than one year from the date of Substantial Completion.
15.2 Exhaust fan and makeup air unit manufacturers shall provide their standard equipment warranty, and the DCKV control system shall carry the manufacturer's controls warranty.
NOTE The warranty shall cover the grease-tight integrity of the hood, duct, and fan assembly, including weld and joint failures that permit grease leakage. (15.3)

16 Spare Parts

16.1 The Contractor shall furnish the following spare parts at closeout:
  • One complete set of grease filters or baffle extractors for each hood
  • One set of exhaust fan and makeup air unit drive belts where belt-driven, sized to the installed drive
  • One set of DCKV optical sensor lenses or replaceable sensor elements where the manufacturer provides field-replaceable units
Spare Parts to be Furnishedcheckbox
One set of grease filters / baffles per hood
One set of fan and MAU drive belts (belt-driven)
One set of DCKV sensor lenses / elements

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