CKV Education Center

Commercial Kitchen Ventilation (CKV) Education Center
The importance of Commercial Kitchen Ventilation (CKV) Systems in Commercial Cooking Facilities cannot be overstated. Today’s CKV Systems have become extremely customized heavily engineered systems, consisting of a multiple components. Components such as CKV hood(s), exhaust and make up air system(s), grease extractors and secondary pollution control units, CKV fire suppression system(s), Illumination, Electrical and Life Safety control package(s) some of which may include Demand Ventilation Controls (DVC) and/or Energy Management System(s) (EMS).

The following CKV Education Center is provided in a frequently asked question format and is designed with the intent that it be an unbiased source of information related to CKV hood design, code compliance, performance and operation. The reader is encouraged to review all of the material in the CKV Education Center upon their first visit.

Please do not hesitate to contact Streivor Air Systems with any of your CKV questions that you do not find answers for in our Commercial Kitchen Ventilation System Education Center.

The CKV Hood is where the design of the CKV system starts.

CKV 101 — Learn All about Commercial Kitchen Ventilation by selecting from the questions below.

UL 300 is a fire testing standard administered by Underwriters Laboratories (UL). In order for appliance companies to receive UL labels on their products, each individual model must be submitted to Underwriters Laboratories for testing. The appliances must meet specific requirements in order to be approved and certified as UL 300.

Before 1994, most commercial cooking involved animal fat. The deep fryers that were used were poorly insulated which made cooking temperatures inconsistent and in-efficient. The extinguishing unit that protected those kitchens was a dry-chemical system which would smother the fire. Today, vegetable oils are used in commercial cooking and they heat to cooking temperatures quickly. Today’s deep fryers have excellent heat retention and are well insulated.

Dry chemical systems are no longer capable of extinguishing and sustaining an extinguished fire. UL 300 systems use wet chemicals which serve two purposes: 1.) To smoother the fire, similar to the way dry chemicals did; and 2.) To cool the liquids so they don’t re-ignite, something dry chemical systems couldn’t do. Although a system might be labeled as wet chemical, it may not necessarily be rated to the UL-300 standard. If you have any questions about your system, contact your suppression service company.

Ashrae 90.1 standardNational Standard ANSI/ASHRAE/IES 90.1 and the State of California’s Title 24 Energy Code are standards that mandate Demand Control Kitchen Ventilation (DCKV) or other energy saving strategies are incorporated into the commercial kitchen ventilation design, whenever a total kitchen has exhaust airflow rate greater than 5,000 CFM. Streivor’s DemandAire™ Control Systems meet these standards.

A CKV Hood is a device that is designed to capture and contain, heat, steam, and other effluents that are generated from commercial cooking.

Commercial Kitchen Ventilation

CKV hoods are separated in to two Type of Hoods: Type I and Type II.

A Type I hood is hood that can be used to exhaust heat, steam, grease and other effluents generated from commercial cooking. The code and standards detail construction requirements for Type I hoods that depict a hood that is much more substantial than a type II hood. A Type I hood must be designed withstand the demands of continuous high temperatures grease laden cooking. (see example to the right)

Type I Grease Extraction Hood

A Type II hood is a hood that can be used to exhaust heat and steam only. A Type II hood cannot be used to when grease other effluents other than heat and steam are generated during the cooking process. (see example to the right)

Type II Vapor Hood

The primary function of a CKV hood is to serve as a fire control and safety device. The CKV Hood Must be manufactured and installed in compliance with all local, state and national prevailing codes. Do not even start down the design path with a hood manufacture until you are convinced that their hood will meet all of the requirements of the prevailing codes and standards that apply to your specific installation.

Commercial Kitchen Cooking Safety Considerations

You should contact the Authority Having Jurisdiction (AHJ) such as the building and/or fire department that will be issuing you your building permits. The AHJ will notify you which codes and standards your project will have to adhere to and comply with.

The CKV restaurant hood most often is required to adhere to and comply with National Mechanical Codes, such as the International Mechanical Code (IMC), Uniform Mechanical Code (UMC), state Mechanical Codes such as California Mechanical Code (CMC) and the National Fire Codes such as The National Fire Protection Agencies Standard 96 (NFPA 96).

To learn more about how to insure that you choose a code compliant CKV Hood read, “Specifying and Inspecting Commercial Kitchen hoods

The major factor in determining if you will need to install a Type I or Type II restaurant hood will be the cooking equipment that you install under the hood regardless of what type of products and/or cooking technique you plan on using. An example of this is, if you are installing an enclosed convection oven and you only plan on using that oven for baking, the code implies that you can install a Type II hood because the products being cooked and the cooking technique will only create effluents of heat and steam. However, the AHJ may demand that a Type I hood be installed do to the fact that enclosed convection ovens can also be used to cook other food products such as proteins, in which case the effluents would contain grease laden particles.

The ultimate determination of the Type of CKV hood that you will need to install will be made after your cooking equipment plan and menu are reviewed with the AHJ.

If you are performing holding, reheating, baking, or using an enclosed deck type pizza oven that produces only heat and steam you may be able to use a Type II Restaurant hood.

Note:  that you will have to consult with the Authority Having Jurisdiction for final determination.

A Commercial Kitchen Hood, like other products such as electrical appliances, can obtain a listing through a third party testing and certification laboratory (laboratory). A hood manufacturer can contract with a laboratory and have their product tested to the prevailing standard. If the manufacture proves that they can meet all of the requirements of the prevailing standard they then can contract with the laboratory to place the laboratories mark on their product. The manufacturer will be subject to quarterly unannounced inspections to insure the listed product is manufactured in accordance with its listing. The manufacturer can continue to display the laboratories mark as long as the manufacturer is in good standing and can prove they are in compliance with their listing to the laboratory.

The two certification and testing laboratories that are currently listing CKV hoods in the United States of America are Intertek (ETL) and Underwriters Laboratories Inc (UL). The hood may be referred to a UL listed and/or ETL listed hood based on the Laboratory that the hood is currently listed with.

UL Listed Logo
ETL Intertek Logo
title24-lThe California Energy Code, or Title 24, Part 6 of the California Code of Regulations, also titled The Energy Efficiency Standards for Residential and Nonresidential Buildings, were established in 1978 in response to a legislative mandate to reduce California’s energy consumption. The standards are updated periodically to allow consideration and possible incorporation of new energy efficiency technologies and methods.

The Energy Commission adopted the 2008 Standards on April 23, 2008, and the Building Standards Commission approved them for publication on September 11, 2008. The 2008 Residential Compliance Manual was adopted by the Commission on December 17, 2008, and the 2008 Non-residential Compliance Manual was adopted January 14, 2009.

The requirement for when the 2008 standards must be followed is dependent on when the application for the building permit is submitted. If the application for the building permit is submitted on or after 1/1/10, the 2008 standards must be met.

  1. The Energy Commission adopted the 2008 changes to the Building Energy Efficiency Standards for a number of compelling reasons:
  2. To provide California with an adequate, reasonably-priced, and environmentally-sound supply of energy.
  3. To respond to Assembly Bill 32, the Global Warming Solutions Act of 2006, which mandates that California must reduce its greenhouse gas emissions to 1990 levels by 2020.
  4. To pursue California energy policy that energy efficiency is the resource of first choice for meeting California’s energy needs.
  5. To act on the findings of California’s Integrated Energy Policy Report (IEPR) that Standards are the most cost effective means to achieve energy efficiency, expects the Building Energy Efficiency Standards to continue to be upgraded over time to reduce electricity and peak demand, and recognizes the role of the Standards in reducing energy related to meeting California’s water needs and in reducing greenhouse gas emissions.
  6. To meet the West Coast Governors’ Global Warming Initiative commitment to include aggressive energy efficiency measures into updates of state building codes.
  7. To meet the Executive Order in the Green Building Initiative to improve the energy efficiency of nonresidential buildings through aggressive standards.

UL 710 refers to Underwriters Laboratories Inc Standard #710. UL 710 is the current standard that CKV hoods are tested to and must comply with in addition to all prevailing codes to obtain a listing for their hood.

Currently there is only a standard to test Type I hoods, the UL 710. Type II hoods have no UL Listing.

Not necessarily. Listed hoods provide insurance that the product should have met the current codes and standards when it was manufactured, however the listing does not guarantee that the hood currently meets all of the current prevailing codes and standards. This is one very good reason that purchasing a used a hood is not a good idea unless the purchaser is an expert on hoods and up to date on all of the prevailing codes and standards. The codes are in continuous change and there is no guarantee that a hood that was listed in the past is still compliant with the prevailing codes and standards.

Listed CKV hoods have the advantage of arriving to your installation with the mark of a third party testing and certification listing. Thus you have the guarantee of the manufacture that they are manufacturing their product per their listing and also that the laboratory is certifying that product is being inspected to insure the product is being manufacture in accordance with its listing and the current standard.

Listed CKV hoods also have the advantage that the hood is only required to exhaust the minimum amount of exhaust air that its listing dictates and not the minimum amount the prevailing code dictates.

The prevailing codes provide detailed information on the design and construction requirements that a CKV hood must adhere too. A qualified sheet metal mechanic can design and manufacture a hood to the prevailing codes and thus the hood can meet the codes requirements. CKV hoods do not have to be listed to be installed in a commercial kitchen.

Non-Listed hoods will most likely undergo a more detailed inspection process by the Authority Having Jurisdiction as a result of the lack of third party testing and certification laboratory.

A non-listed hood has the advantage of not having to be manufactured to a specific set of length, height and/or depth dimension as well any specific geometric shape depicted in the manufacturer’s hood listing. Therefore a non-listed hood can be made in any combination of size and/or shape as long as it meets the requirements of the code. This flexibility can be an advantage when things such as columns, beams or other building conditions dictate such things notches, irregular shapes or the position of the exhaust plenum in the CKV hood.

Streivor Non-Listed hood

There are an infinite amount of different CKV hood designs. CKV Hoods for design purposes are broken down into Listed or Non-Listed hoods. Listed hoods will need to be manufactured in accordance with their size and shape listing requirements. Non-listed hoods can be mode any size or shape as long as they meet the requirements of the prevailing code.

 

There are several steps that you will need to take in determining the restaurant hood design that is best for you and your installation.

Step 1: determine the type and amount of cooking equipment that you will be installing in your kitchen. Obtain specification and installation sheets for that cooking equipment. Produce a drawings that shows the positioning of the cooking equipment in the building.

Step 2: obtain and/or detail a set of building condition drawings depicting the area where the hood is going to be installed. It is essential that the hood designer know of any obstructions in the hood area, pipes , ducts, beams, ceilings, walls and the availability of a path way that can facilitate the installation of a duct system that will be the sized to meet the exhaust air requirements of the hood.

Step 3: consult with a person that is a n expert in the field of restaurant hood design and installation. You can contact any of Streivor sales offices or representatives for assistance in choosing the best restaurant hood design for your installation.

Wall Canopy Design CKV HoodThe most common CKV hood design is an exhaust only wall mounted canopy box design Hood (WCBD). The WCBD is designed for the back of the hood to be mounted against a wall, over the top of the cooking equipment and the cooks and is manufacturing in the shape of a rectangle (box). The WCBD design is the most commonly installed hood because of its flexibility, performa
nce and costs.

Flexibility. The WCBD type CKV hoods will accommodate almost all types commercial cooking equipment, including various combinations of that equipment. Equipment such, broilers fryers, griddles and ovens can usually be installed under a WCBD hood.

Performance. WCBD type hoods are very efficient at capture and containing effluents and exhausting them will lower amounts of exhaust air than some other CKV hood designs. The WCBD takes full advantage of an enclosed back wall and large canopy overheard to enhance capture and containment capabilities.

Value. WCBD type CKV Hoods make up the a large share of the market place thus they are produced in larger quantities, the larger production rates of the WCBD design reduces the market price the WCBD type CKV hoods.

The minimum amount of exhaust air that is required in a CKV hood is determined by the type of cooking equipment that will be installed under the hood, the temperature at which that cooking equipment will be cooking at, the design of the hood and the amount of open sides that the hood has, i.e. how many sides of the hood are up against a wall or is the hood installed in an island application.

Listed hood designs are individually tested for capture and containment over temperature controlled cooking equipment by a third party testing and certification lab. The results of capture and containment test are documented and included as part of the hoods listing. The manufacture can then engineer the minimum exhaust air flows of that hood design per the details of that hoods listing.

Non-listed CKV hood designs must meet the requirements of the prevailing codes. The prevailing codes generally provide formulas that are dependent on the type of cooking equipment and the temperature that the cooking equipment is intended to operate at, as well as the amount of open sides of the hood. Some code formula also take into consideration the distance that the CKV hood will be form the cooking equipment.

The minimum amount of air that a listed CKV hood is required to exhaust is determined by capture and containment tests that were observed by the third party testing and certification laboratory on each specific design. Each listed hood design has its own listing requirements and must be installed in accordance to them.

Yes, there are definitely some kitchen hoods that are manufactured with more efficient designs that allow the hood to operate at lower exhaust air flows. Streivor’s patented SmartAire™ hoods can give up to a 40% savings in energy efficiency.

The position of the cooking equipment and the inclusion of adjacent back and side walls or the lack thereof can have a significant effect on the amount of exhaust air that is required to obtain full capture and containment. Positioning the cooking equipment with the hottest cooking temperature closest to the center of the hood can reduce exhaust airflow requirements and vice a versa, positioning the cooking equipment with the hottest cooking temperatures closet to the sides of the hood will increase exhaust air flow requirements.

Walls adjacent to CKV can significantly reduce the minimum amount of exhaust airflow that is required to achieve capture and containment. Hoods that are installed against a back wall will generally require 50% less exhaust airflow than hood that are installed in a Island application with no walls.

Yes!
Active Front Edge Air Curtain
The capture and containment efficiency of a CKV hood can be greatly increased by mechanically introducing streams of air to the lower front edge of the hood. The air streams create an active edge increase the hoods ability to capture and contain effluents at lower exhaust air flow. The streams of air must be made up of an extremely low volume of air while at the same time maintaining a very high velocity of travel. Hoods with an active front air edge can be as much as 40% more efficient than hoods with similar designs without an active front air edge.

Containment Panels
Containment panels are usually made of the same material as the CKV hood and are either fastened or welded to the open side of the hood. The containment panels enclose the hood and reduce amount of hood open area. The containment panels also significantly reduce the negative effects of makeup air or other air currents round the hood. Containment panels generally come in two sizes heavy duty and light duty. Hoods with heavy duty or light duty containment panels can be as much as 20% and 10% respectively more efficient than similar hoods without containment panels.

SmartAire Canopy Hood and Energy Efficiency

You should consult the prevailing codes and AHJ before installing a CKV hood to verify the required clearances to a type I Hood. Generally a Type hood will require 18” of clearance to a combustible material, 3” to a limited combustible material and 0” to a non-combustible material. Most CKV manufacturers offer accessories called stand offs or air spaces that can be added to the CKV hood to insure proper clearances are maintained and enclosed.

(See Page 7)

The minimum amount of exhaust air that is required in a type II CKV hood is determined by the type of cooking equipment that will be installed under the hood, the temperature at which that cooking equipment will be cooking at, the design of the hood and the amount of open sides that the hood has, i.e. how many sides of the hood are up against a wall or is the hood installed in an island application.

There is no current standard for listing Type II CKV hoods in the United States of America, thus the prevailing codes and standards should be consulted for determined minimum exhaust air flows.

Make up air refers the air that must be introduced into the kitchen to make up air that is being removed by the CKV exhaust system. The codes generally mandate that the exhaust system create no more than a .02 inch water column negative pressure in the kitchen.

The most common ways of introducing make up air into the kitchen are:

  1. through the CKV hood,
  2. through perforated supply plenums either mounted to the CKV hood or in the ceiling around the CKV hood
  3. through ceiling diffusors located in the general are of the CKV hood
  4. through the buildings HVAC system
  5. through a combination of 1, 2, 3 & 4

Many CKV hood manufactures have designed hoods that include a make up air plenum as part of the hood. The make up air is introduced into the hood form the make up air system and exits through the hood into the room.

Hood with Make Up Plenum

The advantages of introducing make up air through the CKV Hood are,

  1. CKV hoods have the potential to provide a large diffused area for the return of the make up air, thus facilitating a potentially lower air speed of the make up air returning into the kitchen.
  2. Reduces the amounf of space the make up air system my occupy in the attic and ceiling.
  3. Potentially Simplifies the Design and Installation processes by eliminating the need to engineer a makeup air diffusor system with multiple diffusors thought put the kitchen.
  4. Potentially lowers the cost of the make up air system and the installation of it by eliminating multiple duct runs and diffusors.
  5. space by eliminating the need for additional plenums or diffusors located outside of the CKV hood.
WCFS Wall Canopy Front Supply Hood

A: 

  1. Perforated Supply Plenums have the potential to provide a large diffused area for the return of the make up air, thus facilitating a potentially lower air speed of the make up air returning into the kitchen.
  2. Potentially Simplifies the Design and Installation processes by eliminating the need to engineer a makeup air diffusor system with multiple diffusors thought put the kitchen.
  3. Potentially lowers the cost of the make up air system and the installation of it by eliminating multiple duct runs and diffusors.
Supply Plenum on Restaurant Hood

Most national mechanical and fire codes and standards require that the CKV hood’s exhaust fan be running anytime that the cooking equipment under is in use. If CKV exhaust’s fan is not on when the cooking equipment is in use most codes and standards require that there be a system in place that can automatically turn the exhaust fan on.

CKV hoods can be fitted with temperature monitors that have an adjustable temperature setting. The temperature monitors are set to a point slightly above the standard ambient operating kitchen temperature. When the temperature monitors detect temperatures above the standard ambient kitchen temperature, the monitor closes a switch that can be used to energize the CKV hood exhaust fan.

Most National Mechanical and Fire Codes and Standards require that the CKV hood’s exhaust fan be running anytime that the cooking equipment under it is on. If CKV Exhaust’s fan is not on when the cooking equipment is turned on the codes and standards require that there be a system in place that can automatically turn the exhaust fan one.

Auto Fan Start and Enclosures

Auto Fan Start in Streivor Enclosure.

CKV hoods can be fitted with temperature monitors that have an adjustable temperature setting. The temperature monitors are set to a point slightly above the standard ambient operating kitchen temperature. When the temperature monitors detect temperatures above the standard ambient kitchen temperature, the monitor closes a switch that can be used to energize the CKV hood exhaust fan.

Auto Fan Start
Smartaire technology

SmartAire™ Technology

The CKV hood that is considered the most energy efficient is the hood that can be installed over cooking equipment and exhaust the lowest amount of exhaust air.

An example of an energy efficient hood is a hood that uses advanced aerodynamic technology that incorporates airstreams into the front lower edge of a hood that create an active front edge that reduces the amount of exhaust air that is required to facilitate capture an containment in similar hoods by as much as 40%.

 

 

Unfortunately no. The only part of a CKV hood system that can qualify for LEED point credits for Demand Control Kitchen Ventilation (DKCV) Systems. Streivor’s DemandAire™ qualifies for LEED points and has met the technical requirements to receive the EPA’s ENERGY STAR® Emerging Technology Award.

Demand Ventilation Controls can be added to the CKV Systems to vary the exhaust and make up air fan during different levels of operations, such as peak or off peak cooking times.

Demand Control Kitchen Ventilation

Demand Control Kitchen Ventilation (DCKV) is a system that incorporates sensors that monitor the state of the CKV hood, CKV hood duct, and/or cooking equipment. The monitors provide information on the state of the CKV components and send information to a control panel that varies the amount of power that is supplied to the exhaust and make up air fans. A DCKV system will reduce the amount of energy the CKV System is using by turning down the fan power during off peak cycles.

DemandAire Demand Control Ventilation System

Yes, Demand Control Kitchen Ventilation (DCKV) can qualify for LEED point credits.

Yes, currently several energy companies offer rebates for approved Demand Controlled Kitchen Ventilation (DCKV) Systems.

(WCLC) Wall Canopy Low Clearance Hood

Grease Extractors in Type 1 Hood

 

Grease filters or grease extractors are required in all type I CKV hoods? Even though the name implies that the most important function that the grease filter or extractor serve is to extract grease form the exhaust air stream that is actually a secondary function. The most important function the grease filter or extractor provides is as a fire barrier preventing a fire from traveling from below the filter up into the duct system.

No, the percentage of grease extraction efficiency is dependent on the design of the grease filter.

Grease Extraction Efficiency

The national codes and standards require that all grease filters for Type I CKV hoods be listed to the Underwriters Laboratories Standard #1046.

UL 1046 is the standard by which Grease Extractors are tested to.

CKV Type II hoods do not require grease filters.

Some grease filters have adjustable features incorporated in their designs that allow the static pressure created by the filter to be increased or decreased. The ability to increase or decrease the static pressure can be beneficial in controlling airflows with in the CKV hood.

No, the amount of grease extraction is dependent on the design of the grease filter.

There are no current national codes or standards that include a minimum grease extraction efficiency that a filter for a CKV Hood must achieve; currently there are several air quality management districts that are considering minimum grease extraction efficiency requirements for filters for CKV hoods.

Multi Stage Filter Cartridge

Multi Stage Filter Cartridge with Filtration Mesh

A multi-stage grease filter is a filter that has a primary filter and additional stages of filter downstream of the primary filter.

Multi-stage Cartridge Air Flow

Multi-stage filters generally have significantly higher grease extraction efficiencies when compared to single stage filters.

Mutli-Stage Cartridge for CKV Hoods

Aluminized Stainless Steel

Aluminized Stainless Steel

Stainless Steel 430

Stainless Steel 430

The most commonly used metals that CKV hoods are manufactured from are Stainless Steel, and Aluminized Steel.

CKV hoods are manufactured form several type of stainless steel, The most commonly used material are 304 and 430 stainless steel.

Type 304 stainless steel is a high grade of stainless steel that includes a minimum of 8% nickel.

Type 430 stainless steel is a lower grade of stainless steel that includes a minimum of 4% nickel.

Read More

The benefit of using type #304 verses #430 stainless steel is that the #304 is better suited for the harsh environment that a Type I CKV must withstand. The 304 material will better withstand the harsh degreasers and other chemical that are used during the hood and duct cleaning, the chemicals that make up the kitchen fire suppression as well as the effluents that pass through and/or collect on the CKV hood as a result of cooking and kitchen cleaning applications.

The CKV hood should be designed to hold under regular use for up to 40 years. The increased cost of using type 304 verses 430 is a small price to pay for a lot of adding protection depreciated over a 40 year period.

Aluminized steel is steel that is coated with aluminum during the milling process.

Aluminized metal can be used in the non-exposed portions of a CKV hood, such as the exhaust plenum. When it is imperative to reduce the costs of the CKV hood, substituting aluminized metal in the non-exposed portions of the hood can be a consideration.

Listed variable volume dampers may be installed in the hood or ducts to facilitate CKV hood balancing.

Balancing Dampers

National mechanical and fire codes generally allow balancing dampers to be installed in CKV hoods and ducts under the condition that the dampers are listed and installed in accordance with their listing. Streivor’s BalanceAire is a UL 710 Listed Restaurant Hood Balancing Damper.

The two most common types of balancing dampers for type I CKV hoods are opposed blade dampers and guillotine dampers. Streivor’s Balancing Dampers are UL 710 Listed for Type I Restaurant Hoods

BAL-EdgesAn opposed blade is a damper that has two or more blades that are fixed with the damper housing in an opposed position relative to each other. The blades are adjustable. By moving one or more of the blades the resistance created by the blades on the air passing through the damper can be increased or decreased. Streivor’s BalanceAire is a UL Listed Kitchen Hood Balancing Damper.

The advantage of using an opposed blade damper verses a guillotine damper, is that a guillotine damper is designed to create resistance to the air flowing through the duct by sliding a blade into the duct opening, usually from one side. This type of dampering will cause un even air flows through he duct system.

Opposing blade Damper