Design of Kitchen Ventilation

Systems

T H A N K YO U F O R AT T E N D I N G

2013New Ideas & Technologies

Design Considerations• Performance • Heat • Humidity• Comfort• Energy• Cost• Fire safety and prevention

Too often, the Kitchen is...

As suggested by John A. Clark, P.E., Minneapolis

•Too Hot•Too Noisy•Too Smelly•Too Greasy•Too Slippery•Too Expensive•Too Energy Consuming

Commercial Building Energy Consumption

Food Service

Food Sales

Health Care

Other

Lodging

Office

Education

0 50 100 150 200 250 300

Thousand BTUs

SustainableFoodservice.com

Energy Use in Restaurants

16.4%

15.7%

24.4%

6.8%

16.6%

5.6%

4.7%

9.8%

RefrigerationSanitationFood PrepCoolingHeatingVentilationOthersLighting

Refrigeration

15.7%Sanitation

24.4%Food Prep

16.6%Heating

6.8%Cooling

999999999 8%%%%%%Lighting

5.6%Ventilation

44444 777777%%%%%Other

SustainableFoodservice.com

HVAC 29%

Integrated Design Approach & Future

INTEGRATED DESIGN

1. Designed as systems instead of pieces and parts, from hood to fan

2. Understanding type, load and volume of cooking

3. Robust performance at lowest exhaust (CFM)

4. Improved kitchen/ building comfort and IAQ

5. Fire prevention and safety including grease duct design

6. Demand control ventilation becoming standard for many applications

IMC• Section 507 - Commercial Kitchen Hoods

• 507.2.1 Type I Hoods: Type I hoods shall be installed where cooking appliances produce grease or smoke, such as occurs with griddles, fryers, broilers, ovens ranges and wok ranges.

• Require fire suppression, listed filters and grease duct.

• 507.2.2 Type II Hoods: Type II hoods shall be installed where cooking or dishwashing appliances produce heat, steam, or products of combustion and do not produce smoke, such as dishwashing machines.

Schlieren Technology

What the Eye Sees

Courtesy of FSTC CKV Lab

Effluent Drawn from the Hood by Exhaust Fan

How Hoods Work

Effluent Circulation

Courtesy FSTC

End Panel Performance

Courtesy FSTC

End Panel Design Options

Minimum 6” Overhang

Courtesy FSTC

18” Front Overhang

Courtesy FSTC

Recommended Overhang

OVERHHANGEQUIPMENT FRONT SIDECharbroiler 18” - 24” 12”

Fryer or Griddle 12” 6” - 12”Conveyor Oven 12” 12” past conveyor

Convection Oven* 24” 6”Upright Broilers 18” - 24” 12”

Solid Fuel 24” 24”Woks 24” 24”

Dishwasher 12” 24” inlet & discharge

** General overhang recommendations for wall canopy hoods for improved capture and containment performance **

Size of Hood Reservoir•Hood should contain surges of effluent:

- Door Openings- Lid Openings

- Turning Food- Lowering Baskets

of Food Hood should be

Centered over Applianceand Larger

Hoods• Appliance Positioning

- Heavy Duty Appliances in the middle of the line (charbroiler)

- Light Duty Appliances on the end of the line (ovens)

- Push Back Appliances

- Group Like Duty Appliances together

SUSTAINABILITY

Equipment Classification

Light Duty Equipment

(400-450° F)

Medium Duty Equipment

(400-450° F)

Heavy Duty Equipment

(600° F)

Extra-Heavy Duty

Equipment (700° F)

Ovens

Cheesemelters

Rethermalizers

Steam-Jacketed Kettles

Compartment Steamers

GriddlesFryers

Pasta CookersTilting SkilletsBraising PansRotisseries

Conveyor (Pizza) Ovens

Open-Burner Ranges

Electric/Gas Underfired

Broilers

Salamander (Upright) Broilers

Chain Broilers

Wok Ranges

Appliances using Solid Fuel

(Wood, Charcoal, Briquettes and Mesquite) to provide all or

part of the heat source

*Equipment Classifications from IMC

IMC• Section 507.1 General:

Commercial kitchen exhaust...• Exceptions:

Factor-built commercial exhaust hoods which are tested in accordance with UL710, Listed, Labeled, and installed in accordance shall not be required to comply with sections:

• 507.4 Type I Materials• 507.7 Hood joints, seams, penetrations• 507.11 Grease filters• 507.12 Size and location• 507.13 Capacity (Exhaust Air Rate Calculations)• 507.14 Non-canopy size and location• 507.15 Exhaust outlets

Exhaust Rates (Listed vs. IMC)Type of Hood

UNLISTEDIMC MINIMUM REQUIRED CCFM per Linear FFoot of Hood

UNLISTED Light Duty Equip Medium Duty Equip Heavy Duty Equip Extra-Heavy Duty Equip

Unlisted Wall-Mounted Canopy

200 300 400 550

Unlisted Backshelf 250 300 400 Not allowed

Type of HoodLISTED

TYPICALL LISTED CFM pper Linear Foot of HoodLISTED

ETL / UL 710Light Duty Equip Medium Duty Equip Heavy Duty Equip Extra-Heavy Duty

Equip

ListedWall-Mounted Canopy

150-200 200-300 200-400 350+

ListedBackshelf 100-200 200-300 300-400 Not

recommended

Effluent• Includes gaseous, liquid and solid contaminants

• Products of combustion - Carbon Monoxide, Carbon Dioxide and Nitrogen Oxide

• Grease Characteristics:- Both Vapor, Small and Large

Particles

- Grease Vapor is ~ 30-90%

- Hotter Cooking Process = more grease vapor

Grease Emissions

Grease Emissions

Grease Problems•Greasy Exhaust Fans

• Environmental Impact

•Rooftop Damage

•Grease Accumulation behind the filters

• Significant Buildup on Fusible Links

• Fire Hazard with Grease Accumulation in the duct and plenum

INTEGRATED DESIGN

Filter Efficiency TestASTM F2519: “Grease Particle Capture Efficiency of Commercial Kitchen Filters and Extractors”

- Pressure Drop as a function of airflow through the filter

- Particulate Capture Efficiency by particle size

Incorporation of filter selection and affect on design of entire system, including IAQ.

INTEGRATED DESIGN

Visual Performance Test

System design incorporates make-upair tempering and delivery strategy

Makeup Air Problem?

INTEGRATED DESIGN

IMC• Commercial Kitchen Makeup Air

• 508.1 Makeup Air. Makeup air shall be supplied during the operation of commercial kitchen exhaust systems that are provided for commercial cooking appliances. The amount of makeup air supplied shall be approximately equal to the amount of exhaust air. The makeup air shall not reduce the effectiveness of the exhaust system. Makeup air shall be provided by gravity or mechanical means, or both. For mechanical makeup air systems, the exhaust and makeup air systems shall be electrically interlocked to insure that makeup air is provided when the exhaust system is in operation.

IMC• Commercial Kitchen Makeup Air

• 508.1.1 Makeup Air temperature. The temperature differential between makeup air and the air in the conditioned space shall not exceed 10°F.

• Exceptions:1. Makeup air that is part of the air-conditioning

system2. Makeup air that does not decrease the comfort

conditions of the occupied space

Makeup Air: How & Why

• Air removed from the kitchen through the hood must be replaced.This can be achieved by the following pathways:

• Transfer Air• Displacement Diffusers, floor or wall mounted• Ceiling Diffusers (4-way, slot diffusers)• Perforated Ceiling Diffusers• Exhaust Hood with Integrated Makeup Air

What’s wrong with this picture?

4-Way Diffuser - Causing Spillage

Courtesy FSTC

Engineered Makeup System?

Dedicated MUA

http://www.energy.ca.gov/reports/2003-04-10_500-03-007F.PDF

Designing for Dedicated MUA

Dedicated ‘Local’ Makeup Air:

• Typical 70-80% of exhaust

• Proper air velocity is critical

• Correct design, placement

• Enhanced performance

• Minimal diffusion

• Less heating and cooling

• Temperature 55° to 85°F

• Improved comfort

Temperature is important!

• Hood performance• Comfort conditions• HVAC heating / cooling

performance + comfort + efficiency

INTEGRATED DESIGN

Poor capture performance in field

Robust capture performance in field

ELECTRICAL controls

Electrical Codes• Light control• Fire system integration• On/Off control or demand ventilation• Interlock of exhaust fan and make-up air unit• Auto-on integration

IMC 2006, Section 507.2.1.1Type I hood systems shall be ... installed to automatically activate the exhaust fan whenever cooking operations shall occur through an interlock with the cooking appliances, by means of heat sensors or ... other approved methods.

INTEGRATED DESIGN

Variable Speed Exhaust?

Fan Energy - Savings & Penalties

Cooking Exhaust Temperature

�������

100.389

75.973

129.976

77.593

129.09

77.307

70

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90

100

110

120

130

140

6:00:2

0 6:3

0:20

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Tem

pera

ture

(F°)

Time

Grillhouse Pagoda

Pizza Hacienda

Large Buffet Chain RestaurantRaleigh, NC

Demand Ventilation Systems

• Automatically adjusts exhaust and makeup air fans

• Temperature sensor and variable frequency drives modulate fans speed

• Satisfies IMC 507.2.1.1, automatic activation requirement

• Rebates and incentives from many utility companies

Grease Duct Issues• Size and velocity• Static pressure drop• Integrity of the welds and joints• Number of tees and elbows• Radius not mitered elbows• Access for cleaning• Clearance requirements

Leaking Grease Duct

Duct ConstructionIMC 2009, 506.3.2Joints, seams and penetrations: continuous liquid-tight weld or braze made on external surface

- Exceptions:1. Penetrations shall not be required... where sealed by devices listed for

application2. Internal welding shall not be prohibited provided that the joint is formed

or ground smooth and provided with ready access3. Factory-built commercial kitchen grease ducts listed and labeled

Clearance to Combustibles

NFPA 96-2008 Appendix

Hinged upblast exhaust fan

Roof

Ceiling

Exhaust Hood

10 ft

40inches

18 inches

Grease DuctText

IMC 2009506.3.6 Grease duct... serving a Type I hood shall have a clearance to combustible construction of not less than 18 inches (457 mm), and shall have a clearance to noncombustible construction and gypsum wallboard attached to noncombustible structures of not less than 3 inches (76 mm).

Factory Built Grease Duct• Listed to UL 1978 (Single)• Listed to UL 2221 (Double)• Exceptions:

- Grease duct materials

- Joints, seams and penetrations

- Duct-to-Hood joints

• Improved fire safety• Requires no welding• Zero clearance to combustible

INTEGRATED DESIGN

Ductwork Design• Correct size and velocity• Static pressure drop estimated accurately• Minimize number of tees and elbows• Radius not mitered elbows• Access for cleaning• Use of listed ductwork - integrity of welds

verified with dye testing• Double Wall ductwork where applicable

UL1978 Testing

Temp & Abnormal Temp Test

Access Door Test

UL2221 Testing

External Engulfment Test

UL2221 Testing

Internal Fire Test

Recent Fire

UL300 Testing for Hood Fire Suppression System

Factory Built Grease Duct

Summary• System design for kitchen ventilation

systems- critical• Equipment under hood is #1 thing to

understand• Make-up air strategy • Controls- how will system work with

building• Ductwork for fire safety and decreased

energy

INTEGRATED DESIGN

Questions?

INTEGRATED DESIGN