How to Size a Commercial Kitchen Exhaust System

Written by louis gutierrez
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How to Size a Commercial Kitchen Exhaust System
A properly installed exhaust system removes smoke and reduces odour in the kitchen. (Stockbyte/Stockbyte/Getty Images)

Commercial kitchens like those in restaurants require a properly sized exhaust system. While local fire and building codes will dictate specific sizing requirements, most localities use a standard reference guide. A licensed HVAC contractor and engineer must design and install the system, but you can verify on your own that they are sizing your exhaust system correctly. Failure to install the correct-sized system can lead to a fire hazard or the added expense of a larger exhaust system than needed.

Skill level:

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Things you need

  • Tape measure

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  1. 1

    Measure the width and depth of all your cooking equipment. Add 6 inches to the depth and 12 inches to the total width. This is the minimum size the exhaust hood must be. If you expect your cooking equipment eventually will grow in size, compensate by buying a wider exhaust hood.

  2. 2

    Read the manual for the hood to determine the volume of airflow required for the exhaust fan. The size of the exhaust fan will vary depending on the layout of the kitchen and hood design.

  3. 3

    Calculate the size of the supply air fan. The exact sizing and use of a supply air fan will vary depending on local building code. On average, most supply fans are sized at about 85 per cent of exhaust fan airflow. For example, if your kitchen hood requires a 4000 CFM exhaust fan, you must install an air supply fan of 3400 CFM (or 85 per cent of exhaust fan airflow.)

  4. 4

    Install a fire suppression system that fits with your exhaust hood. Reference the manual of the exhaust hood for a compatible fire suppression system, or ask the vendor of the exhaust hood. In some counties it is optional to install a fire suppression system.

Tips and warnings

  • Installing a fire suppression system can lead to a discount on your commercial insurance.
  • Only a licensed HVAC (Heating, Ventilation and Air Conditioning) engineer can design a commercial kitchen exhaust system.

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