Signs & diagnostics
Grease dripping from a canopy or its filters is not a cosmetic nuisance - it is the outside finally showing what the inside has been holding for weeks. It means the filters and duct are saturated, capture is falling, and the fire fuel in the system has built past a safe level.
The short answer
Grease dripping from a canopy or its filters is not a cosmetic nuisance - it is the outside finally showing what the inside has been holding for weeks. It means the filters and duct are saturated, capture is falling, and the fire fuel in the system has built past a safe level.
The detail
Baffle filters are the first defence, spinning grease out of the airstream by making it change direction. They are designed to catch the bulk of it, but they have a limit. Once they are saturated, grease carries past them into the plenum and duct, and only when the whole path is loaded does it begin to weep back down to the visible edge.
So a drip at the lip is a late signal, not an early one. The grease you can see is the overflow from a system that is already coated inside. That is why contractors treat visible dripping as advanced contamination rather than a minor housekeeping issue to wipe away.
It matters for airflow because the same saturation that produces the drip is raising resistance across the filters and duct. The fan moves less air, capture velocity at the canopy face falls, and more of the plume - heat, steam and ungrabbed grease - spills into the room to settle on surfaces.
It matters more for fire. Grease in the duct is combustible fuel. Industry banding treats a mean around 200 microns as acceptable, 200 to 999 as needing cleaning, and 1,000 microns or more as a high fire risk. Grease heavy enough to drip is well into the range where a clean is not optional.
What it means for you
TR19 Grease sets a mean cap of 200 microns and requires immediate localised cleaning at any single reading of 500 microns or more. Dripping grease is a strong indication you are at or beyond the spot-clean point somewhere in the system, so the honest answer to how urgent is: promptly.
There is also a compliance edge. The Regulatory Reform (Fire Safety) Order 2005 makes controlling fire risk from grease your duty, and insurers increasingly want to see a current TR19 Grease certificate. A visibly dripping system is hard to defend if an inspector or assessor arrives.
Phoenix Duct Clean will inspect, measure the deposits, clean the canopy, filters, plenum, duct and fan back to below the verification threshold, and document it with photos and readings - turning a dripping, undefendable system into a proven-clean one.
The service behind the guide
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Questions
It is a clean-now sign rather than a call-the-brigade emergency, but it should not wait for the next scheduled visit. Grease heavy enough to drip means the duct is loaded, capture is falling and the fire fuel in the system is high, so prompt cleaning is the right response.
Wiping the visible edge does nothing about the saturated filters and duct behind it, which is where the drip is coming from and where the fire risk sits. The surface will simply re-wet. Only a full internal clean addresses the cause.
It rarely builds suddenly - it builds invisibly. Grease loads the filters and duct over weeks until the whole path is saturated, and only then does the overflow appear at the lip. The drip is the first outward sign of a long-running buildup.
It can. If dripping returns quickly after a clean, either the interval is too long for your grease load or the previous clean did not reach the full system. A borescope inspection and micron readings will show which.
Cleaning stops the current problem. Keeping it away means matching the cleaning interval to your actual grease output, which a cleanliness risk assessment sets - heavier frying and longer hours need more frequent visits than the baseline.
Phoenix Duct Clean · by the numbers
This is a clean-now sign. Call and we will inspect, measure and clear the system fast.