How metal foam grease filtration works
A metal foam hood filter is a single piece of open-cell stainless steel foam. Exhaust air is forced through a three-dimensional network of metal struts, and grease aerosols impact and condense on that internal surface instead of passing into the duct. The same tortuous path is why a foam filter keeps capturing grease across its whole thickness, while a baffle filter only deflects droplets at its surface. PrometheanFoam kitchen hood filters are rated at 95%+ grease and smoke capture, are made from A1 fire-rated non-combustible stainless steel, and are sized to drop into standard hood filter slots.
Sizes and fit
The standard filter measures 500 × 700 mm (19.7" × 27.6"). To check fit, measure the inside dimensions of your existing baffle filter slot — the foam filter replaces the baffle one-for-one, with no hood modification. Non-standard hood sizes, different thicknesses and multi-filter kits are available through our custom manufacturing service. If you run a restaurant group or a central kitchen, see how the filters are deployed at scale on our commercial kitchens solution page.
Cleaning and maintenance
There is nothing to replace on a schedule. About once a month, take the filters out and wash them — they are dishwasher safe and clean in about 5 minutes; heavily loaded filters can be soaked in degreaser first. With monthly cleaning, the expected service life is 3–5 years, compared with the weekly replacement cycle of disposable or baffle-style filters. A clean filter also keeps grease out of the ductwork, which supports your NFPA 96 grease-control and hood-cleaning routine and reduces the grease load your duct cleaners have to remove.
Metal foam vs baffle filters
Baffle filters rely on direction changes to fling grease onto the baffle surface; fine aerosol largely passes through. Metal foam captures by interception through its full depth, which is why capture stays high between cleanings. Our engineering comparison, Baffle Filters vs Metal Foam: Engineering Analysis, walks through the capture mechanism, pressure drop and lifetime cost in detail. Not sure foam fits your hood? Order a sample kit and test it in your own kitchen first.
