Kitchen exhaust fans seem like such a simple piece of equipment when you think of a restaurant and its entirety, including everything that goes into the overall operation and functionality.  However, restaurateurs who have spent a decent amount of time in the heart of the industry know better than that. The reality is that these fans are the core functioning piece of the puzzle for a restaurant.   According to Beth, Hoods Department Manager, the fan is the “heart and soul of a restaurant.” Choosing to ignore the proper maintenance and scheduling of regular cleanings for fans can ultimately result in a significant loss of money and a potential shut down of the restaurant indefinitely.

A simple explanation for an exhaust fan, is a mechanical ventilation device that creates an airway for impure or contaminated air to freely pass through your vent and draw in the clean air to your restaurant.   In turn, the fan will improve the indoor quality of air. Any restaurant that maintains cooking equipment and produces smoke is required to have an exhaust system to remove flammable fumes from the air within the kitchen. This is vital to any restaurant:  to not only improve the quality of air within the establishment, but to ensure the safety and well-being of all customers and employees who enter the facility.

There are many styles of fans within restaurants:  Upblast, Utility, In Line, and Downblast.   Each fan has a separate function and procedure to best fit its environment and benefit the overall quality of air within the facility; it helps to protect employees and customers.

The determining factors for selection of a fan is based on such variables such as high temperature, grease content of the air encountered, the exhaust system, as well as the fans ability to handle friction, distance and airflow resistance.  In order to prevent roof and building damage, exhaust fans should be selected to direct air away from the rooftop and the building.

Types of Fans

Upblast Fan

The most common fan used for exhaust systems, and usually found in most standard restaurants is the upblast fan, or the “mushroom” fan. This particular type of fan is in high demand, due to its low rate in cost and user-friendly installation process. Most fast-food, casual and fine dining restaurants will utilize this style fan. The housing of the up-blast fan is constructed of aluminum, that comes with a list of requirements when being installed on a rooftop.  Phil Ackland’s “Commercial Kitchen Exhaust Systems Manual” states:

  • Must be listed for commercial cooking use
  • Must be able to drain grease out of any trap or low point into a non-combustible container or collection device
  • Must have a grease collection device
  • Must be hinged and have a flexible weatherproof electrical cable to allow for cleaning

Utility Fan

Utility fans are also commonly found in commercial cooking establishments, and are made with steel instead of aluminum. This type fan is made for a stronger and more durable application, compared to the up-blast fan, and has a more powerful motor and lift. The lift refers to the CFM (cubic feet per minute) and is the measure of air being moved or “lifted” up through the fan. Utility fans differ from up-blast fans in that they cannot be tipped (meaning tilted) and require access from the rear-side of the fan housing. They are typically more difficult to clean and require additional maintenance due to the amount of ductwork that runs into the fan.

In-Line Fans

This particular fan is frequently used for applications where it’s a larger system and there are some constraints on how the ductwork runs through the building. Typically, they will be placed where the ductwork may run into a parking garage. High-rise buildings that have a ground level restaurant are encouraged to use this type of fan because it will benefit them in the best way to facilitate their establishment.

Down Blast Fans

The down Blast fan is normally not appropriate for use in kitchen exhaust due to design and performance of this particular style. The down blast fan (downdraft fan) would not be suitable for a standard restaurant that produces a large amount of grease because this style fan blows the grease down into the ductwork instead of lifting it out.


Frequency of Cleaning

Common Issues

Some common issues are:

  1. Rattling – due to lack of maintenance components or parts become defective.    Most rattles are caused by excess grease buildup on the fan blades or a worn belt. Usually, a good cleaning and belt change will fix the rattling.
  2. Screws – They help keep the fan in balance and from bouncing around which can not only damage the fan, but other assets around the fan.
  3. Wiring Malfunctions –  Wiring can melt due to the fan being dirty causing it to work harder than usual, or the belt becomes loose or worn. Frayed or loose wires happen due to excessive movement, which is usually caused from normal wear (opening and closing a fan).

Beth, says there are many concerns:

  1.  “A major issue is when customers do not purchase access panels, which inhibits proper cleaning.”   Access panels are necessary in kitchen exhaust systems where the ductwork has areas not accessible for proper cleaning. Without access panels, grease tends to build up in the areas of the ductwork that the cleaners cannot get to, which can cause additional problems such as fires, foul odor and even a contaminated working environment”.
  2. Ductwork – “Before a cleaning, a technician needs to see a blueprint of the ductwork or at least some general documentation as to what type ductwork the location has, and whether or not they need access panels to complete the cleaning.
  3. Lack of Maintenance of the fan and the roof containment system – “These two items significantly increase the chance of grease leaks.  Grease leaks occur when the fan blades are not properly running, or the housing of the fan is not thoroughly cleaned. The housing of the fan can be tricky to clean since it’s the protective covering for the motor and electrical wiring. If grease leaks onto the roof of a building, it will eventually destroy the roof and can cost upwards of $18,000 + for repair and or replacement.  The solution to grease issues include proper cleaning schedule as well as a grease containment system.”


Grease containment systems provide a significant amount of protection from grease damage by trapping the grease. There are two primary types of grease containment systems:  hi-capacity and the side-kick. The hi-capacity grease containment system is the most expensive, but decreases the chance of most grease leaks. This style is primarily designed for restaurants that produce a high volume of grease. It uses a combination of grease absorbing pads with a four-sided application, to insure all grease is captured.  The side-kick variation differs in that it is designed for applications that produce much lower volumes of grease. This version includes a container on one side of the fan, instead of all four, along with the grease absorbing pads to reduce the risk of grease leaking onto the roof. By protecting the roof, working areas surrounding the fan will be kept safe for the technicians, who come to service the fans on a regular basis and ultimately end up saving the customer money.

Hinge kits are a vital part of the fan that too often get overlooked on installation. However, without hinges, your fan will not meet NFPA-96 code ( requirements.  Without hinges there can potentially be roof and electrical damage during cleanings, due to the fan being placed directly onto the roof. Often times, the fan will cut wires or cause holes in the foundation of the roof if placed improperly. Hinge kits allow for safer and easier cleaning underneath the fan and down in the duct by tipping the fan instead of completely lifting it off the exhaust system onto the roof. This allows easier accessibility for the service technicians to complete their cleaning in the most efficient way.

Consistent maintenance of the fan in a restaurant is one of the primary defenses against fire hazards. “An estimated 5,900 restaurant building fires occur annually in the United States, resulting in an estimated average of 75 injuries and $172 million in property loss.” The cleaning process includes the exhaust of the hood, all ductwork and the exhaust fans. Typically, during a cleaning, technicians collect the grease buildup and remove it from the entire system so that it does not end up in the restaurants floor drains. In order to remove all grease particles from the hood, duct and fan, these technicians may use a variety of different sanitizing methods including:  chemical degreasers, scrubbing, and power pashing. Quality control is vital during these cleanings to ensure compliance with all applicable municipal, state and NFPA codes in order to stay in business and pass each inspection. Upon completion, a Proof-of-Performance label is to be posted on the hood.  SLM – Facility Solutions Nationwide insists upon further documentation for all of its clients where service issues, documentation of the type cleaning along with before and after photos are all posted to its web-site for client portal viewing 24/7/365.   This Proof-of-Performance label assures when the cleaning was done as well as to assure the Fire Marshall the system was cleaned properly.

By keeping up with the maintenance of your kitchen exhaust fan, your restaurant will benefit from greater energy savings, improved health standards, a cleaner working environment and minimized product contamination.  The money you spend on preventative maintenance cleanings and repairs is drastically less than what you would incur in damages that would have occurred without the consistent maintenance. The risk of fire hazards will significantly decrease and you will remain in compliance with local municipal fire codes. Not only that, but your equipment will preserve their quality of life and save you many future headaches.




  6. Phil Ackland’s Commercial Kitchen Exhaust Systems Manuel