Cleaning kitchen exhaust (KEC) systems is required by law in order to avoid fire hazards from excessive grease buildup for restaurants and commercial kitchens. Methods of cleaning are generally proscribed by NFPA 96, Standard for Ventilation Control and Fire Protection of Commercial Cooking Operations 2017. Requirements for inspection and cleaning include grease removal devices, exhaust systems, hoods, fans and cooking equipment. Eliminate non-storm water discharges by controlling all water, grease, solvents, cleaners and other fluids generated in the cleaning process. Do not allow grease or solvents to contact roof surfaces, gutters, parking lots or other areas that receive rainfall.
Exhaust systems generally consist of an exhaust hood, plenum, filters or baffles, exhaust ductwork vertical/horizontal, and a roof fan. Each exhaust system tends to be unique due to - different combinations of possible equipment - restaurant layout and design - building architecture and constraints Hoods and filters are usually made of stainless steel, galvanized steel or aluminum in order to facilitate regular cleaning. Exhaust ductwork is usually made of fabricated black iron, and are required to be leak-proof so that cleaning with pressure washing equipment can take place. Common types of roof fans are upblast, utility set, and supreme. Disposal of any cleaning or wastewater discharges onto the ground, or any surface that washes off into the storm drainage system or natural streams, is a direct violation. Many restaurants and other smaller businesses may not know whether a particular drain leads to the storm drain system or the sanitary sewer system. Procedures using smoke, dye tests or air monitoring equipment can also be used to identify sanitary sewer lines. All grease, chemical and residue(s) removed from an exhaust system during cleaning should be diverted to the facilities grease trap
Typical Kitchen Exhaust Cleaning Procedures Kitchen exhaust cleaning is a multi-step operation designed to clean all of the system components to bare metal. This operation must be planned in order to clean each component thoroughly while protecting surrounding areas, by working from the top down. Protect workers by disconnecting electricity to the exhaust cleaning system. A variety of cleaning equipment and supplies (degreasers, brushes, scrapers etc.) should be on hand. The following is a typical list of exhaust cleaning procedures for each hood:
· Erect a funnel of plastic sheathing underneath the hood in order to collect wastewater and grease coming down the fan riser and connecting ductwork. The plastic sheathing (wrap) must be securely fastened along all edges, in order to protect cooking equipment and surrounding areas. The wrap must be structurally supported or braced to handle the expected amounts of wastewater.
· Remove filters and grease/drain cups from the hood. Hand scraping areas of the system can be required. Clean these components down to bare metal by soaking with chemical degreasers and then rinsing with high-pressure water. It is always best to remove any thick grease first, and dispose of grease properly
· Clean the roof exhaust fan inside and out, down to bare metal, using chemical degreasers and then rinsing with high-pressure water.
· The exhaust ductwork is sprayed with chemical degreaser and then rinsed with high-pressure water. Remove exhaust duct access doors in vertical and horizontals as necessary to clean and inspect the interior of the exhaust system.
· The plenum and interior of the exhaust hood are sprayed with chemical degreaser and then rinsed with high-pressure water.
· Allow the hood/all ductwork /fan system to fully drain. Remove plastic and dispose as solid waste.
· Dry the exhaust hood, and polish stainless steel surfaces as necessary. Replace filters and drain cups. Clean and polish wall surfaces in the immediate vicinity. An approved “hood sticker” should be placed on the hood depicting when service was completed and when the next service is due. Mop floors as needed. There are several local companies that provide kitchen exhaust cleaning services; these companies must be familiar with NFPA 96, 2017 in order to properly inspect, clean kitchen exhaust systems. Cleaning Resource Center prides itself with detailed service reports and a full assortment of pictures. CRC has specialized equipment and the proper supplies to perform the work quickly and efficiently. In general, our service kitchen exhaust cleaning is performed late at night or during weekends to allow the maximum amount of time for cleaning. Restaurant operators should rely only on qualified contractors for kitchen exhaust cleaning. Grease and Wastewater Recovery for commercial kitchens and restaurants are required to have a grease trap as part of the sanitary drain system in the cooking area. In addition, most kitchens and restaurants typically have an outdoor grease receptacle for the disposal and recycling of thick grease, and fryer oil etc. Whenever thick grease is encountered, it should be scraped from the surface and placed into the outdoor grease receptacle. This will increase the maintenance interval of a grease trap, and helps to ensure the sanitary sewer systems will function adequately without adverse results. During the entire process of kitchen exhaust cleaning, there is a substantial amount of wastewater generated. It is illegal to discharge this wastewater outdoors onto the ground or parking lot, into a ditch or storm drainage system. Any wastewater that contains grease is typically poured into a mop sink or floor drain that leads to a grease trap. Cleaning Methods for Exhaust Roof Fans Exhaust fans typically are the hardest elements to clean. There are more surfaces for grease to accumulate on (fan blades, bowl). Heavy accumulations of grease can put undue stress on fan motors, bearings and drive belts (due to the excess weight). Exhaust fans must be cleaned thoroughly, inside and outside, inside and outside of the fan blades. Do not clean near catch basins, ditches, pipes or any part of the storm water drainage system. Collect wastewater and rinse water by appropriate means for disposal into the interior sanitary drains. Exterior portions of the fan casing should be cleaned and rinsed by hand when necessary. However, a tarp or plastic sheathing is commonly used to contain wastewater and high-pressure water while cleaning the exterior surfaces. Utility Set Fan: Utility Set fans usually have an integral water collection drain on the bottom, which simplifies the process of cleaning the interior surfaces. Collect wastewater into a watertight container, which can then be emptied into an interior sanitary drain leading into the grease trap. The exterior surfaces of the Utility Set fans may be cleaned by hand; there is generally a miniscule amount of grease on these surfaces. Supreme Fan: Supreme fans have an integral grease collection tray with a ball valve spout. This allows the interior cleaning wastewater to be collected into a watertight container, which can then be emptied into an interior sanitary drain leading into the grease trap. Wastewater from cleaning the underside of the fans will run down the stack. Supreme fans have the fan motor and blades mounted on a pivoting assembly that pops out of the fan housing. Ensure that all wastewater is collected when washing the fan blades and housing assembly. Upblast Fan: Upblast fans have an integral water collection spout on the bottom, which simplifies the process of cleaning the interior surfaces. Collect wastewater into a watertight container, which can then be emptied into an interior sanitary drain leading into the grease trap. Wastewater from cleaning the underside will run directly down the ductwork. Upblast fans are required to have a hinge kit for easy tipping that also avoids damages. Ensure that all wastewater is collected when washing the fan blades and housing assembly. Roof Wastewater Collection Methods Do not allow any roof wastewater or cleaning water into the municipal storm water drainage system, ditches, catch basins, natural creeks and streams, etc. Preferable methods for cleaning exhaust roof fans will not generate uncontrolled wastewater or rinse water on roofs. A watertight tarp can be securely fastened along all edges around an exhaust fan, with some sort of structural support or bracing to handle the expected water amounts. A child-sized swimming pool can be easily altered to perform as structural support for a watertight tarp. As an alternate method, the roof itself can be used to store or contain wastewater. Then the low point of the roof can be used as a collection point for grease and wastewater, which is then vacuumed and safely disposed. If needed, gutters or downspouts can be temporarily stopped and then used as a collection point. Wastewater must be collected into a suitable containment. The contaminated roof areas must be cleaned and rinsed a few times. Maintenance ¾ Inspection of kitchen exhaust systems should occur weekly, monthly or as recommended by the equipment manufacturer. Cleaning and maintenance of kitchen exhaust system filters should occur weekly or monthly. Keep adequate records of inspections and maintenance work at the restaurant or kitchen location. Records must be made available to AHJ inspectors. Some restaurants or kitchens may have space or access limitations that hamper efforts to inspect and clean kitchen exhaust systems. This may necessitate the removal of ovens, exhausts, or other types of kitchen equipment on a regular basis to adequately inspect kitchen exhaust systems.