According to a National Fire Protection Association survey conducted between 2000 to 2004, of approximately 8,520 structural fires in eating and drinking establishments including: restaurants, cafeterias, diners, nightclubs, dinner theaters, taverns, lunchrooms, fast food facilities and snack bars have caused an annual average of 3 civilian deaths, 113 civilian fire injuries, and $190 million in direct property damage.

It is important to note that major causes of fire in eating and drinking establishments, the leading cause of restaurant fires occurred by cooking. Furthermore, grease accumulations were found to be a contributing factor to the expansion of smaller fires into larger fires. When an exhaust system is cleaned regularly the chances of a duct fire become extremely remote. According to statistics, the peak time for fires is between 9:00 am and noon. These are the times when food is either prepared or served. Kitchen fires are less common between 9 p.m. and 8:59 a.m., when most establishments are closed. Cooking equipment was responsible in approximately half of the structural fires in eating and drinking establishments.

Grease removal in kitchen exhaust systems is a continually evolving subject. The key to proper and effective grease removal and the prevention of fires is a combination of properly designed, installed and maintained exhaust systems coupled with scheduled inspections and maintenance.

Kitchen exhaust cleaning is required by law for all commercial cooking establishments such as restaurants, hospitals, hotels, employee cafeterias and other food-service locations that have hood and ductwork over cooking equipment to exhaust smoke, grease-laden vapors and fumes out of the building. These exhaust gases leave a grease residue on the inside of the ductwork.

Different cooking equipment as well as different menu selections produces differing amounts and types of effluent. Where steam type cooking equipment leaves little to no grease residue, cooking equipment such as from char broilers, woks, grills, fryers, ranges and upright broilers and other grease producing appliances can leave black, hard or rubbery deposits on the hood, in the duct and on the exhaust fan. Solid fuel cooking uses briquettes, mesquite, hardwood and charcoal which produces large grease laden particulates that quickly clog grease filters and leaves the dirtiest type of cooking emissions. Solid fuel cooking is usually not allowed in commercial kitchens. Due to the additional fire hazard associated with solid fuel cooking, the Bureau of Fire Prevention, Rangehood Unit requires additional safeguards and may grant special permission for its use.

Solid Fuel cooking appliances must be serviced by its own independent kitchen exhaust system and not connected with any other exhaust system. Appliances of this type produce high levels of heat, grease, ash, creosote and smoke. The buildup of grease, ash and creosote on the filters, hoods, ducts and fan is highly volatile. Once ignited this combination of fuel burns at a high temperature.

WARNING: Cleaning could be hazardous due to the presence of electrical components. Before commencement of cleaning prep work, all electrical connections must be disconnected or turned off at the main power source. Electrical shock can cause personal injury or death. Only qualified trained Certificate of Fitness holders should conduct or supervise the cleaning of commercial kitchen exhaust systems. Follow all safety codes and wear safety glasses, work gloves and other pertinent personnel protective equipment (PPE) during cleaning. An ABC portable fire extinguisher should be made available during cleaning.