Common Kitchen Exhaust System Deficiencies and Why They Matter

Kitchen Exhaust outside from building

Whether you’re building a new restaurant or installing a kitchen into an already existing commercial building, it’s important to understand the various aspects of kitchen exhaust systems that are specifically designed to keep them fire safe. The goal of a kitchen ventilation system is to safely deliver the flammable vapors emitted from cooking operations from stovetop to rooftop. This prevents the kitchen from being coated in a layer of flammable grease as well as absorbs other substances commonly diffused during cooking such as smoke. In order for the exhaust system to do its job properly, it must be maintained, cleaned regularly, and in working order. More specifically, there are certain components of your kitchen exhaust system you should pay special attention to and guarantee they are built or maintained correctly to keep your facility safe.

According to NFPA 96 regulations, the most common deficiencies found among kitchen exhaust systems include:

Ductwork Construction

NFPA 96 states:

5.1.2 – All seams, joints, and penetrations of the hood enclosure that direct and capture grease-laden vapors and exhaust gases shall have a liquid tight continuous external weld to the hood’s lower outermost perimeter.

Kitchen exhaust ventilation ductwork should be built so that it can contain the heat and flames caused by a potential fire for up to 2 hours. This time window protects the facility as a whole and allows the proper fire safety authorities to react and arrive on site in time to prevent total destruction of the building. When ductwork is not properly built in the first place, a structure fire could result in a total loss and cause incredibly costly damages. Ensure that all connectors, corners, access panels, and vent hood are properly sealed and welded so that no flame can escape or leak into other parts of the building in the event of a fire. Inspection of the kitchen exhaust system for any deficiencies on code 5.1.2 can be done through a light test by the installer, or through a complete system wash by your hood cleaning vendor, noting any section of the duct that leak out grease or water.

Access Doors in Ductwork

NFPA 96 states:

Access Doors in Ductwork

3.1 – Openings shall be provided at the sides or at the top of the duct, whichever is more accessible, and at changes of direction.

4.1.2 – Where an opening of the size specified in is not possible, openings large enough to permit thorough cleaning shall be provided at 3.7m (12 ft.) intervals.

1.6 – A sign stating the following shall be placed on all access panels: ACCESS PANEL—-DO NOT OBSTRUCT

The proper location and construction of access doors throughout your ductwork is crucial for regular maintenance cleaning. Regularly scheduled kitchen exhaust cleanings prevent hazardous grease buildup that puts your facility at risk. Without the proper access doors installed so that a vendor can clean all aspects of your ductwork, they may not be able to clean the entire system and leave portions uncleaned. These unreachable areas are considered “inaccessible” according to code 11.6.14, NFPA 96. Bare Metal Standard doesn’t believe in inaccessible areas of your kitchen exhaust system as these present an incredible fire safety hazard for your facility. Bare Metal Standard always cleans to 100% of your kitchen exhaust system, no matter what.

Exhaust Fan Installation

NFPA 96 states:

Kitchen Exhaust Fan at building Top – Upblast fans with motors surrounded by the airstream shall be hinged and supplied with flexible weatherproof electrical cable and service hold-open retainers.

The top and bottom exhaust fans must also be entirely accessible and properly cleaned on a regular basis. A hinge kit, as well as a flexible electrical connection to the exhaust fan, allows the cleaning vendor to safely access the bottom of the fan and get into the interior of the ductwork from the rooftop.

These common deficiencies in kitchen exhaust systems can result in very real consequences if a fire were ever to occur. It’s essential as a facility or restaurant owner to keep your kitchen exhaust system clean and maintained as a fire safety precaution. Did you know your local Bare Metal Standard offers FREE complete kitchen exhaust system inspections? You can have your entire system checked for deficiencies as well as receive a quote for cleaning services if you’re currently not up to fire code. We’re here to help, so always feel free to call your local Bare Metal Standard for inspection and cleaning services for your commercial kitchen exhaust system.