Home / Kitchen Extraction Cleaning / Guide
Extraction cleaning - what surveys reveal
A grease loading survey does more than confirm what you already suspect. Time and again, surveys uncover things the kitchen did not know: grease far heavier than expected, build-up hiding in sections no one could reach, access panels missing exactly where they were needed. Here are the kinds of things a grease loading survey typically uncovers - and why what it reveals is the point of doing it.
The short answer
What a grease loading survey typically uncovers falls into a few recurring patterns. Grease heavier than expected: the measured build-up often turns out worse than the kitchen assumed, because grease accumulates out of sight and is easy to underestimate. Build-up in unreachable sections: surveys frequently find grease loaded in parts of the system that no access panel reaches, so those sections have never been properly cleaned and have accumulated grease and fire risk unchecked. Missing or poorly placed access panels: the survey often reveals that the access provision is inadequate - panels missing where they are needed, so the system cannot be fully cleaned as it stands. And uneven build-up: grease concentrated at bends, low points and the fan far more than elsewhere. These are the things the kitchen did not know - and uncovering them is exactly why the survey is worth doing.
Grease heavier than expected
The most common thing a grease loading survey uncovers is that the grease build-up is heavier than the kitchen expected. Because grease accumulates inside the ductwork, out of sight, it is easy to underestimate - the visible parts, the filters and canopy, might be cleaned regularly and look reasonable, while the hidden ducts have loaded up far more than anyone realised. When the survey measures the actual grease depth, the figures often come back higher than assumed, revealing a system more loaded than its outward appearance suggested. The kitchen thought the extraction was in reasonable shape; the survey shows the ducts are heavily grease-lined.
This gap between the assumed and the measured state is exactly why measuring matters. Judging the state of the ductwork by eye, or by how the accessible parts look, is unreliable, because the important build-up is hidden. The survey replaces that guess with figures, and the figures frequently reveal that the grease has built up further than thought - which means the fire risk is higher than assumed and cleaning is more overdue than realised. So a very common survey outcome is a kitchen learning that its system needs cleaning more than it knew. That is not a failure of the kitchen; it is the nature of a hidden build-up, and it is the first thing a survey is valuable for uncovering: the true, measured state behind the outward appearance.
Grease where no one could reach
A second common and serious finding is grease built up in sections of the system that no one could reach to clean. Ductwork needs access panels to be cleaned inside, and if a run of duct has no panel giving access to it, that section cannot be properly cleaned - so grease accumulates there, clean after clean, never being removed. Surveys frequently uncover exactly this: a stretch of ductwork, often a concealed run or an awkward section, that has no access and has therefore been quietly loading with grease for as long as the system has been running, unnoticed because no one could see or reach it. It is often the most heavily loaded part of the whole system, precisely because it has never been cleaned.
This is a significant finding because an unreachable, heavily loaded section is a concentrated fire risk that the routine cleaning has never touched. The kitchen may have been having the accessible parts cleaned diligently, believing the system was maintained, while a hidden section built up unchecked. The survey uncovers this by tracing the system and checking the access throughout, revealing the sections that cleaning has been missing. And uncovering it is what allows it to be fixed - typically by fitting access panels so the section can finally be reached and cleaned. Without the survey, the unreachable build-up would carry on unaddressed indefinitely, a hidden fire risk no one knew was there. So finding the parts that cleaning cannot reach is one of the most valuable things a survey does.
Missing and misplaced access
Related to the unreachable sections, surveys commonly uncover that the access provision is simply inadequate - access panels missing where they are needed, or placed so that they do not give access to the whole run. Good practice is for access panels to be provided at regular intervals along the ductwork and at every bend and at the fan, so that the entire internal system can be reached and cleaned. In reality, many systems - especially older ones, or ones installed without cleaning in mind - have far fewer panels than they should, leaving gaps that cannot be reached. The survey checks this and often reveals that the system needs additional panels fitted to be fully cleanable.
This is a finding that matters for the long term, not just the current clean. A system with inadequate access will keep having sections that cannot be cleaned every time, so the access shortcoming is an ongoing problem, not a one-off. Uncovering it lets it be put right - fitting the panels needed so that future cleans can reach the whole system - which changes the system from partly-cleanable to fully-cleanable going forward. So the access finding is about fixing the system's cleanability for good, not just this time. Surveys uncovering missing or misplaced panels is common enough that it is one of the routine valuable outcomes: the survey does not just assess the grease, it assesses whether the system is built to be kept clean, and frequently finds it is not - which is the first step to fixing it.
Uneven build-up and hidden hot spots
A further thing surveys uncover is where the grease actually concentrates - which is often not where the kitchen would guess. Grease does not line the ducts evenly; it builds up much more heavily at certain points: at bends, where the airflow changes direction and grease drops out; at low points, where grease collects and pools; and at the fan, where grease accumulates on the blades and housing. Surveys frequently reveal that while the general duct runs carry a moderate build-up, these particular spots have loaded up far more - hidden hot spots of concentrated grease that are the real fire-risk points in the system. The kitchen would not know this without the survey mapping the build-up point by point.
Uncovering the hot spots matters because they are where the risk is concentrated and where cleaning most needs to reach. A clean that addresses the easy general runs but misses the heavily loaded bend or fan leaves the worst of the build-up in place. The survey, by revealing where the grease concentrates, ensures the cleaning targets those points - so the real hot spots are cleaned, not just the accessible average. So the survey's mapping of the uneven build-up is not academic: it directs the cleaning to where it matters most. Together with the heavier-than-expected total, the unreachable sections and the missing access, the hidden hot spots are among the things a grease loading survey routinely uncovers - the things the kitchen did not know, which knowing changes what gets done.
The takeaway
A grease loading survey routinely uncovers things the kitchen did not know. Grease heavier than expected, because a hidden build-up is easy to underestimate and the measured figures often come back worse than the outward appearance suggested. Grease loaded in unreachable sections that no access panel reaches, which have never been properly cleaned and are often the most heavily loaded, most concentrated fire risk in the system. Access provision that is inadequate - panels missing or misplaced, so the system cannot be fully cleaned as it stands. And hidden hot spots where the grease concentrates - at bends, low points and the fan - far more than the general runs.
Uncovering these is the point of the survey. Each is something the kitchen would not otherwise know, because the build-up and the access shortcomings are hidden inside the system - and each changes what the cleaning needs to do: reveal the true level so the clean is not underestimated, find the unreachable sections so they can be made reachable, identify the missing panels so access can be fixed for good, and map the hot spots so cleaning targets them. So a grease loading survey is worth doing precisely for what it reveals: the hidden state of the system, which knowing lets you address properly. What it uncovers is what turns cleaning from a guess into a job done in full knowledge of what the system actually needs.
Questions
Recurring patterns: grease heavier than expected, because a hidden build-up is easy to underestimate; build-up in unreachable sections that no access panel reaches and that have never been properly cleaned; access panels missing or poorly placed, so the system cannot be fully cleaned; and hidden hot spots where grease concentrates at bends, low points and the fan. These are the things the kitchen did not know.
Because it accumulates inside the ductwork, out of sight. The visible parts - filters and canopy - might be cleaned regularly and look reasonable, while the hidden ducts have loaded far more than realised. When the survey measures the actual depth, the figures often come back higher than assumed, revealing a system more loaded, and a fire risk higher, than its appearance suggested.
Runs of ductwork that no access panel gives access to, so they cannot be properly cleaned. Surveys frequently find a concealed or awkward section that has been quietly loading with grease for as long as the system has run, never cleaned - often the most heavily loaded part of the whole system, and a concentrated fire risk the routine cleaning has never touched.
It checks the access provision throughout and reveals where panels are missing or misplaced, so the system cannot be fully cleaned as it stands. Uncovering this lets it be put right - fitting the panels needed so future cleans can reach the whole system. That fixes the system's cleanability for good, not just for the current clean, changing it from partly to fully cleanable.
Points where grease concentrates far more than the general duct runs - at bends, where the airflow changes direction and grease drops out; at low points, where it pools; and at the fan, where it builds on the blades and housing. Surveys reveal these hot spots so the cleaning can target them, rather than addressing the easy runs and missing the worst of the build-up.
Because each is hidden and changes what the cleaning needs to do - revealing the true level so the clean is not underestimated, finding unreachable sections so they can be made reachable, identifying missing panels so access is fixed for good, and mapping hot spots so cleaning targets them. What the survey uncovers turns cleaning from a guess into a job done in full knowledge of what the system needs.
Our survey uncovers what your system is really carrying - heavier grease, unreachable sections, missing access, hidden hot spots - so the clean that follows addresses what is actually there, not just the easy parts.
