Commercial Kitchen Ventilation
The ventilation system is an integrated system that is designed to capture, contain and exhaust products of the cooking process. Please reference Indiana Mechanical Code.
Exhaust Air
Appliance exhaust air is the starting point in restaurant kitchen ventilation design. Exhaust air is the air that is contaminated by smoke and grease-laden vapor (aerosols) created by the cooking source. This air must be removed from the building in a manner that complies with state and local codes and ordinances.
Replacement Air
Make-up or, supply air, must be provided in approximately equal amounts to replace the kitchen air being exhausted. Typically, outside air is supplied through a designed make-up air system. Most health codes require that an amount of fresh outside air be included in any replacement air calculation to assist in indoor air quality requirements.
Capture and Containment Of Vapors & Heat
The kitchen ventilation system size and design is determined by the appliances to be used. There are important considerations, such as:
- Appliance Type
- Duty Rating (BTU)
- Fuel Source
- Size and Cooking Surface
Exhaust System Components
A typical kitchen ventilation system (type I hood) includes:
- Duct work
- Exhaust fan
- Exhaust hood
- Fire system
- Means of providing adequate make-up air
The entire system must constitute a fire-safe assembly within the building.
Basic Commercial Kitchen
The basic commercial kitchen exhaust system is composed of the following components:
- Exhaust Hoods
- Grease Filtration Systems
- Exhaust Duct
- Exhaust Fan
- Make Up Air
- Automatic Fire Suppression System (other auxiliary component)
Capture & Containment
"Hood capture and containment" is defined by ASTM F170405, "Capture and containment performance of commercial kitchen exhaust ventilation systems," as "the ability of the hood to capture and contain grease laden cooking vapors, convective heat and other products of cooking processes."
- Hood Capture = products getting into the hood reservoir
- Containment = products staying in the hood reservoir and not spilling out into the room
In order for a ventilation system to operate correctly, all of the ventilation components must be sized and rated for the cooking operations.
New Construction
For new construction, the appliance selection should be the first step. The ventilation system selection should follow. The type of appliance and the heat it generates will impact the hood size and rating; the fan size which then will determine the make-up air requirement.
Existing Systems
Existing ventilation system efficiency and effectiveness is not as easy to evaluate since the appliances may have been replaced or alterations to the ventilation system may have occurred. If there is an indication of insufficient exhausting, a capture and containment test may be recommended. Indications of this include:
- Cooking odors present away from the hood
- Discolored ceiling
- Greasy floor
Ventilation Performance Test
The purpose of exhaust hood smoke capture testing is to prevent condensation accumulation and dripping and ensure containment of:
- Fumes emitted by the cooking equipment
- Heat
- Obnoxious odors
- Smoke
- Steam
- Vapors
Verification
Capture needs to be evaluated at all exposed sides of the hood.
- Verify that the exhaust system operates when cooking operations occur (normal cooking temperature).
- Verify that the exhaust fan and make-up air system start and operate simultaneously.
- Verify make-up air is tempered.
Performance Evaluation
Acceptable performance consists of capture of all visible smoke generated. A demonstration is a complete testing of all identified test locations. A complete and thorough ventilation system evaluation will ensure that when the system is properly maintained and operated, it will capture effectively.
- Operate all the appliances to simulate normal cooking conditions.
- Use smoke to visualize spillage.
- Test front and sides.
Final Report
A final ventilation balance report should be submitted prior to the capture and containment test. The ventilation balance report is to agree with the air quantities stipulated on the approved plans and specifications for the installation.
Test Conditions
- Movement of persons is to be minimized.
- Interior or exterior doors, windows, drive-thru windows, and roof hatches are to be kept closed.
- All equipment (exhaust, make-up air, rooftop unit, HVAC, etc.) that may effect the performance of the hood shall be activated during the test.
Pre-Engineered Fire Suppression System
- Indiana Fire Code 2014
- 904.2.1 Commercial hood and duct systems
- Each required commercial kitchen exhaust hood and duct system required by Section 609 to have a Type I hood shall be protected with an approved automatic fire-extinguishing system installed in accordance with this code.
Standard
NFPA 17A : Wet-chemical extinguishing systems
Testing
UL 300 : Fire Testing of Fire Extinguishing Systems for Protection of Restaurant Cooking Areas