Grease, smoke, heat, odor, pollutants and water vapor from cooking and warewashing-all of these airborne emanations must be removed from a commercial kitchen for the health, safety and comfort of employees and customers, and the efficient operation of the kitchen and equipment. Along with removing unwanted and undesirable effluents from the kitchen, ventilation also exhausts substantial amounts of air. Air that is removed from the kitchen through ventilation must be replaced with an equal amount of outside air, a process known as makeup air. Without adequate makeup air to compensate for air lost during ventilation, the exhaust fan may not pull out all the undesirable products of combustion and cooking and will create a “suction” effect that makes it difficult to open doors.
The amount of ventilation needed in a commercial kitchen is determined by:
• Type of products being cooked
• Structure in which the kitchen is located
• Type of equipment used
• Local regulations
• Building heat source, depending on its location
In response to tightening codes, environmental standards and increasing operating costs, manufacturers are working to find innovative means to provide lower cost installation, start-up and improved operating efficiencies that meet the new safety and environmental standards.
• Two basic types of venting:
>> Atmospheric (or gravity)
>> >> Uses a flue and the tendency of hot gases to rise to exhaust combustion products outdoors.
>> >> Works well for many home appliances.
>> Power venting
>> >> For the strenuous venting demands of most commercial food service kitchens.
>> >> Uses a fan or blower to capture and exhaust the unwanted byproducts of cooking.
>> >> Accomplished with one or more exhaust hoods.
• Two basic types of exhaust hoods:
>> Type I
>> >> For cooking processes that produce smoke and grease
>> >> require liquid-tight construction and a built-in fire suppression system.
>> Type II — Used in situations where only heat and moisture are produced
Two basic styles of ventilation hoods are canopy and backshelf.
• Ventilation hoods exhaust air from the commercial kitchen taking undesirable products of cooking and combustion outside the kitchen and the building. Makeup air equipment replaces exhausted air with clean, fresh and, if desired, heated air.
• Canopy hoods
>> Better suited for tall appliances such as steamers and ovens
>> Used more in facilities that produce large volumes of effluent steam.
>> Flexible as to where they can be placed.
• Backshelf hoods
>> Best suited to low cooking surface appliance such as griddles, grills and fryers
>> Widely used in quick-service and short-order operations.
• Ventilation Systems
>> High-velocity, low exhaust
>> Exhaust only
>> Automatic washdown
>> Removable modular grease extractors
>> Water mist extinquishing system
>> Pre-piped fire suppression system
>> Filter hoods, NFPA-96 hoods
>> Pre-engineered, pre-installed package
>> Rooftop package
>> Wall, single island, backshelf, V-back, double island and proximity styles
>> ETL listed 400°F to 700°F
>> Various custom-designed makeup air plenums
• Makeup Air Systems
>> Packaged HVAC/makeup air systems
>> Natural and power vented furnaces
>> Combustion makeup air/ventilation system
>> Clean air or contaminated air exhaust fans
>> Direct ignition or indirect fired systems
>> Integrated system and safety controls
>> Multiple standard control packages
>> Galvanized metal construction
>> DX, chilled water and evaporative cooling
>> Industrial direct fired horizontal, vertical and compact direct fired heaters
>> Airflows up to 14,000 cfm
>> Inputs from 100 to 1200 MBH
• Improve indoor air quality and reduce cooking and other odors
• Improve occupant comfort and health
• Increase employee productivity and reduce absenteeism
• Improve overall building systems and kitchen efficiency and operation
• Reduce cold air infiltration by heating outside air as it enters the building
• Reduce the infiltration of dust and dirt
*Listed features offered by some, but not necessarily all vendors.