Safety practices for restaurant kitchen exhaust hoods

By Carola Hicks
The foodservice industry must meet higher air quality regulations than standard building exhausts due to the type of contaminated air produced by cooking food.

Restaurants, cafes and other eating establishments are workplaces that are at high risk from fire. This is due to the environment having combustibles in close proximity to hot surfaces and open flames. The most common fires involve unattended cooking, overheating of cooking oil or fat, and the ignition of fatty residues within range hoods and ducting.

Without an effective kitchen exhaust hood cleaning system, cooking grease and smoke cause grit and grime build-up on almost every surface these emissions come into contact with. That can cost you a lot of money in cleaning, maintenance and damage.

Kitchen ventilation includes both exhausting air and providing replacement air to the cooking area. Whether a restaurant is a small free-standing site or a large institutional kitchen, managing and balancing airflow is a complex issue. It is challenging to properly ventilate commercial kitchens, as they require moving large volumes of air through ductwork, and the entire system must be a fire-safe assembly.

Exhaust ductwork provides the means to transfer contaminated air, cooking heat and grease vapours from the hood to the fan. Exhaust fans move the heat and contaminated air out of the building. All exhaust fan components must be accessible or have removable access panels for cleaning and inspection and must be designed to contain and drain any excess grease. Kitchen exhaust cleaning is required by law for virtually every commercial cooking establishment. The ventilation systems should be under a maintenance and service contract and inspected by qualified persons every six months. When an exhaust system is cleaned regularly, the chances of a duct fire are extremely remote.

An owner/facility manager needs to understand the value of having a complete and properly integrated system that will provide a productive and comfortable work environment that is also cost effective and satisfies building codes and fire regulations.

Operations might benefit from lower energy costs while also realizing improved performance-less heat gain and greater personnel comfort. The comfort issue also has economic consequences in terms of personnel performance and turnover costs.

Kitchen exhaust cleaning is a standard part of routine maintenance of any cooking establishment. When the buildup of grease becomes heavy, a fire hazard exists. Approximately one of three restaurant fires is caused by grease. All restaurant owners and managers should be aware of the role routine maintenance plays in fire prevention and ensure it is done on a regular basis.

Here is a common scenario of how a kitchen exhaust fire starts:

A flame flares up on the stove. The fire contacts the filters above the stove, on the kitchen hood. The filters ignite. Since the exhaust fan is on, drawing air into the hood, through the filters and up the duct, the flame on the filters is pulled into the duct. If significant grease residue exists on the duct interior, this can act as fuel spreading the fire up the duct, perhaps all the way into the fan.

Facts

  • 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 leading cause of all restaurant building fires is cooking at 59% and, nearly all of these cooking fires 91%, are small, confined fires with limited damage.
  • Cooking is the leading cause of all restaurant building fires as well as the smaller, confined restaurant building fires.
  • Non-confined restaurant building fires most often start in cooking areas and kitchens, 41%.
  • Deep fryers 9%, ranges 7%, and miscellaneous kitchen and cooking equipment 5%, are the leading types of equipment involved in ignition in non-confined restaurant building fires

Small fires can quickly get out of hand, especially when fueled by poorly maintained equipment such as dirty ventilation systems. Fire is a hazard faced by all commercial kitchens. It only takes a single spark or small gas leak to set a restaurant aflame. Only through proper employee training and following fire safety standards can a restaurant owner protect employees and customers from danger.

About the author

Carola Hicks is CEO of Workplace Safety Group, providing leading-edge, online and in-class health and safety consultation and training programs to associations and specialty industries across Canada. Carola can be reached at carola@workplacesafetygroup.com.

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