Many new restaurant owners or commercial kitchen managers struggle to know how often their exhaust hood fans and ducts should be cleaned. Cleaning the exhaust hoods, ducts, fans and filters are not only important but are required by the law under fire code NFPA 96. Failing to properly maintain the kitchen exhaust hood system can result in fires, unpleasant odors, premature breakdown and catastrophic loss. The grease that builds up in the system provides ample fuel for a fire that can burn at an incredible heat. Most exhaust systems have a fire suppression system within the hood and at the mouth of the vertical duct, but fire suppression systems do not provide protection in the vertical and horizontal ductwork or the fan on the roof.
So how often should a restaurant have their exhaust system cleaned? The frequency of cleaning is something that is highly dependent on the volume of cooking and the type of cooking that you perform. Obviously, higher volume cooking locations require more frequent cleaning. However, what most restaurant owners do not realize is that the type of food their kitchen prepares also plays an important role in how often the exhaust system should be serviced.
For instance, preparing foods that are high in fats and oils (such as cooking burgers, char broil cooking, foods cooked in a wok, cooking with solid fuels (wood) or open vat fryers) deposit much more grease into the exhaust system than traditional cooking. So if you are preparing burgers on a daily basis at a high volume your kitchen exhaust hoods will need to be serviced regularly (quarterly at a minimum) to prevent fires and unacceptable grease buildup.
Determining the optimal level of exhaust hood cleaning that your kitchen or restaurant requires takes years of experience. It is often best to consult with a reputable and certified kitchen exhaust hood inspector who can evaluate your system and cooking habits to provide a recommendation on a cleaning and maintenance schedule. Some commercial kitchen and restaurant hood cleaners provide exhaust hood inspection services for free, and some will even provide pictures of the internal ductwork.
As a rule of thumb no commercial kitchen exhaust system in regular use should go over six months without a thorough cleaning. However, if you are cooking a high volume of foods that are high in fats and oils a thorough cleaning might be required as often as twice a month. This is where the expertise of a certified kitchen exhaust system inspector can help you determine how often your exhaust system needs to be cleaned. Once you have a cleaning and maintenance schedule in place reevaluate the schedule every year to ensure that changes in cooking load or menu options have not increased grease buildup between services.