One of the key functions of a commercial kitchen ventilation system is to remove and filter grease-laden air from the kitchen. Efficiently capturing grease extends the lifespan of a commercial ventilation system, decreases costly duct cleanings, reduces the risk of fire, and contributes to a cleaner community. Filters within the kitchen exhaust hood are the first line of defense against grease accumulation, with optional secondary filtration devices, like pollution control units, providing increased levels of air purification. Selecting the correct products yields the best results and meets both code and clean-air requirements.
Ideally, it is best to capture as much grease as possible at the exhaust hood filters. Doing so prevents build-up of grease within the ducts that may pose a fire risk. Grease fires that occur within the kitchen ventilation system, as opposed to at the cooking source or appliance, are larger and more difficult to contain. They could potentially spread through plenums, ducts, exhaust fans and the roof – compromising the entire building where the kitchen is housed.
Capturing grease efficiently in the exhaust hood filters also creates ongoing savings. Preventing grease from travelling through the entire kitchen ventilation system can help increase the lifespan of each component. Additionally, capturing grease before the airstream enters the ducts prevents build-up and reduces the frequency of expensive duct cleanings. Filters are relatively easy to access, and they can be cleaned in a commercial dishwasher.
To see the benefits of efficient exhaust hood filtration, select products that filter out 69-100% of grease particles that are at least eight microns in size. This can be achieved with filters that extract grease by forcing the air through multiple turns, which will extract between 60-70% of grease. For increased filtration, a dual-stage filter with porous ceramic microbeads can achieve up to 100% efficiency at the eight micron level. More detail on selecting the best exhaust food filter for an operation can be found here.
To provide the same level of filtration efficiency with grease, smoke and odor particles smaller than eight microns, a pollution control unit (PCU) is necessary. These units, often mounted on the roof, achieve high-efficiency grease capture through a multi-stage series of filters. PCUs minimizes the impact grease-laden air has on building surfaces, adjacent equipment and odors that may be disruptive to the nearby community members. They are recommended for high-grease cooking operations, for multi-use buildings, and for regions with stringent clean-air policies.
Pollution control units further filter the airstream after it is initially filtered through the exhaust hood filters. A fully welded or listed grease duct connects the exhaust hood and the pollution control unit. The unit directs air through multiple stages of increasingly efficient mechanical filters or an electrostatic precipitator to remove grease from the exhaust airstream. Lastly, the air passes through carbon trays engineered specifically to neutralize cooking odors.
When selecting a pollution control unit, it is best to choose a product that meets the standards set by UL 8287. This test is designed specifically for pollution control units in commercial kitchens. It provides requirements for electrical requisites and ensures that the unit has no structural deficiencies when tested in a range of temperatures from typical to extreme. This UL Outline, required on all PCUs per IMC 2021, provides ease of mind and ensures a greater level of security when compared to units listed to inappropriate or dated listings, including UL Standards UL 710 and UL 1978.*
Designing a commercial kitchen ventilation system that efficiently filters grease relies on selecting components that work best together to ensure safety, reduce maintenance and keep costs as low as possible. In high-grease cooking environments and multi-use buildings, filtering out grease to create cleaner air has huge ramifications if not accomplished properly. Partner with Accurex for start-to-finish kitchen ventilation expertise that helps owners, staff, patrons and communities breathe easier.
