Regulations and requirements for commercial kitchen hood systems

Opening and maintaining a commercial kitchen is a meticulous process with many steps. Complying with regulations and requirements is mandatory for every establishment in order to maximize safety of the public and staff alike. This is especially relevant regarding exhaust systems due to the risk of fire. 

The National Fire Prevention Association (NFPA) and the International Mechanical Code (IMC) are the go-to entities to consult in order to keep your business running and out of danger. The NFPA, among other things, is responsible for establishing and managing codes related to fire safety in the US, while the IMC is the approved guideline by the International Code Council to regulate all-things-appliances. 

First, let’s review some definitions

There are two types of commercial kitchen hoods, known as Type I and Type II hoods. These hoods are distinguished by the type of materials they filter out of the air.

• Type I Hoods, also known as grease hoods, are designed to remove heat, smoke, and airborne grease. These types of hoods are often found over appliances such as fryers, broilers, grills, and ovens.
• Type II Hoods, sometimes called condensate hoods, remove steam, vapor, and other moisture from the air; some of them even remove odor, so they can be found on top of coffee machines, commercial dishwashers or pizza ovens. These types of hoods often don’t have a grease filter.

Both types of hoods should be installed keeping the following in mind:

• The vertical distance above the cooking surface should not exceed 4 feet.
• The inside lower edge of the hood should overhang no less than 6 inches beyond the edge of the cooking surface it is installed above.
• An approved automatic fire suppression system must be in place. 

Additionally, each type of hood has special requirements:

Type I Hood

• Install your hood at least 18 inches away from combustibles.
• Use approved materials: Any hood in the kitchen should be made of steel with a minimum thickness of 0.0466 inches or stainless steel with a minimum thickness of 0.0335 inches.
• Each hood should include a label indicating the minimum exhaust flow rate in CFM (cubic feet per minute) per linear foot.
• Make sure that each hood is secured in place by noncombustible supports.
• Any external joints, seams, and penetrations should be made from continuous external liquid-tight weld or braze to the lowest outermost perimeter of the hood.
• Internal joints are not required to be welded or brazed but should be sealed so that grease cannot escape.

Type II Hood

• Hood supports should be able to hold the load of the hood, unsupported ductwork, effluent load, and possible weight of any personnel working on the hood.
• Joints, seams, and penetrations for Type II hoods should be sealed on the interior of the hood. The interior should provide a smooth surface that is easy to clean and water-tight.
• Type II hoods should be constructed from steel with a minimum thickness of 0.0296 inches, stainless steel with a minimum thickness of 0.0220 inches, and copper sheets weighing at least 24 oz. per square foot.

According to the NFPA 96 standards, the complete exhaust system of the commercial kitchen must be inspected and cleaned by a professionally trained and certified team or a company. If the inspection shows evidence of a build up of greater than 50 microns of grease-laden vapors in the kitchen hood, the hood system must be cleaned. The system, according to NFPA 96 includes the kitchen hood, filters, fans, fire suppression system, light covers, ducts, grease removal devices, and any metal surfaces.

With all that has to be taken into account regarding exhaust systems, it’s in the best interest of every restaurant owner to rely on experienced teams like ProTech to install and clean commercial kitchen hoods that fulfill every professional standard.

Contact us to discuss your needs and we’ll be happy to take this arduous task off of your plate!