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Kitchen extraction cleaning - glossary
Commercial kitchen ventilation comes with its own vocabulary - canopy, baffle filter, plenum, make-up air, extract fan, TR19 Grease - and it helps to know what the terms mean when talking to an extraction cleaner or reading a report. Here is a plain-English glossary of the main commercial kitchen ventilation and extraction terms you'll come across. This is general information to explain the terms.
The short answer
Talking about a commercial kitchen's ventilation - with a cleaner, an engineer, or in a report - is easier when you know the vocabulary. Here is a plain-English glossary of the main terms, grouped by what they relate to. This is general information to explain the terms. The system's parts: Canopy (or hood) - the hood over the cooking line that collects the rising heat, smoke and grease-laden vapour and channels it into the extraction. Grease filters - the filters set in the canopy that catch grease from the vapour (the first line of defence); the main types are baffle filters (interlocking metal baffles that make the air change direction, flinging out grease) and mesh filters (layers of metal mesh); some systems use cartridge filters. Plenum - the chamber inside the canopy behind the filters, where the filtered air collects before entering the ductwork (grease can build up here). Ductwork (or ducting) - the enclosed runs (the 'ductwork') that carry the extracted air from the canopy away to the outside; grease builds up on the internal surfaces. Extract fan - the fan (usually on the roof or at the duct end) that drives the whole system, pulling the air through and discharging it outside. Riser - a vertical duct run (often in a building's service shaft). The air side: Make-up air (or replacement air) - fresh air supplied into the kitchen to replace the air being extracted (needed to balance the system; without it, the extraction is starved and the kitchen goes into negative pressure). Extract - the air being drawn out (the extraction). Supply - air being supplied in. Standards and cleaning: TR19 Grease - the recognised standard (from BESA) for cleaning grease extraction systems, setting the cleanliness required and a risk-based cleaning frequency (the current grease-specific standard, formerly part of the broader TR19). Access panels - the openings in the ductwork that let a cleaner reach inside to clean it (needed at intervals and key points). Deep clean / decarbonisation - thorough cleaning of the grease. Safety terms: Interlock (gas interlock) - the safety system linking the gas supply to the extraction (gas only flows while the extraction runs). Fire damper - a device in the duct that closes to block fire spread. Fusible link - a heat-sensitive link that releases to close a fire damper. So these are the main commercial kitchen ventilation terms - the parts of the system, the air side, the standards and cleaning, and the safety devices. Knowing them helps you understand your extraction, read a report, and talk to a cleaner. So this glossary explains the ventilation vocabulary. This is general information for reference.
Key points
The parts of the system
The core vocabulary is the parts of the extraction system - the physical components the air passes through. Canopy (or hood): the hood mounted over the cooking line. It collects the rising heat, smoke, steam and grease-laden vapour from the cooking and channels it into the extraction. It is the visible top of the system in the kitchen. Grease filters: the filters set into the canopy, which catch grease from the vapour as it is drawn through - the first line of defence keeping grease out of the rest of the system. The main types are baffle filters (interlocking metal baffles that force the air to change direction sharply, flinging the heavier grease out onto the baffles) and mesh filters (layers of metal mesh that trap grease); some systems use cartridge filters. Plenum: the chamber inside the canopy, behind the filters, where the filtered air gathers before it enters the ductwork - a space where grease can also collect.
Ductwork (or ducting): the enclosed runs of duct that carry the extracted air from the canopy away through the building to discharge outside. This is the hidden part where grease builds up on the internal surfaces (the focus of TR19 Grease cleaning). A vertical duct run is often called a riser (frequently housed in a building's service shaft). Extract fan: the fan - usually mounted on the roof or at the end of the ductwork - that drives the whole system, spinning to pull the air through the filters, canopy and ductwork and discharge it outside. It is the heart of the system (if it fails, the whole extraction stops). So the parts of the system are the canopy, filters, plenum, ductwork (and risers), and extract fan - the path the air takes from the cooking to the outside. So canopy, filters, plenum, ductwork, fan are the parts. This is general information.
The air side
Beyond the parts, some terms describe the air itself and how it is balanced. Extract: the air being drawn out of the kitchen by the extraction system (the 'extract' air). The extraction system's job is to extract this air (carrying the heat, smoke and grease) out of the kitchen. Supply: air being supplied into the kitchen (the opposite of extract). Make-up air (or replacement air): the fresh air supplied into the kitchen to replace the air being extracted. This is important: the extraction pulls a lot of air out, and that air has to be replaced - so make-up air is supplied (through a supply system or ventilation) to balance it.
The reason make-up air matters is balance: if air is extracted but not replaced, the kitchen goes into 'negative pressure' (a partial vacuum) - which starves the extraction (it can't pull air out if none is coming in), makes doors hard to open, causes draughts, and can pull air (and fumes) back down flues. So a well-designed kitchen ventilation system balances the extract and the make-up air. You may see terms like negative pressure (too much extract for the supply) and air balance in this context. So the air side - extract, supply and make-up air - is about the air moving through and being balanced, not just the hardware. Understanding make-up air explains why extraction is part of a balanced ventilation system, not just a fan pulling air out. So extract, supply and make-up air are the air-side terms. This is general information.
Standards and cleaning
Several terms relate to the standards and the cleaning of the grease extraction. TR19 Grease: the recognised standard for cleaning kitchen grease extraction systems, published by BESA (the Building Engineering Services Association). It sets out the required cleanliness (how clean the ductwork must be, measured), the whole-system approach, and a risk-based cleaning frequency (based on how much and what kind of cooking you do). It is the current grease-specific standard - formerly this guidance sat within the broader ductwork standard TR19, and the grease-extraction part is now 'TR19 Grease'. A clean 'to TR19 Grease' means cleaned to this recognised standard, with the verification and records. Access panels: the openings (hatches) built into the ductwork that let a cleaner reach inside to clean and inspect it - needed at suitable intervals along the duct and at key points (bends, fire dampers), so the whole internal length can be reached (you can't clean what you can't reach).
Deep clean / decarbonisation: terms for a thorough clean removing the built-up grease (and, for carbonised/baked-on deposits, 'decarbonisation'). Grease deposit thickness: TR19 Grease relates cleaning to the measured thickness of grease deposits (a very thin film being the target of a clean). Post-clean report / certificate: the records from a clean - a report, before-and-after photographs, and a certificate stating the clean and the standard (evidence for the fire risk assessment and insurers). So the standards-and-cleaning terms - TR19 Grease, access panels, deep clean, and the reports - are about how the grease extraction is cleaned and to what standard, and how it is evidenced. These are the terms you'll meet when arranging and recording an extraction clean. So TR19 Grease, access panels and deep clean are the cleaning terms. This is general information.
Safety devices
Finally, some terms name the safety devices associated with kitchen ventilation. Interlock (gas interlock): a safety system that links the gas supply to the extraction, so gas cooking can only happen while the extraction is running (it proves the airflow and only then permits the gas; if the extraction fails, it cuts the gas). This prevents gas burners running with no ventilation. Fire damper: a device fitted in the ductwork that closes to block the spread of fire through the duct (a barrier that shuts if a fire occurs, helping contain it). Fire dampers are a point that needs access for cleaning and inspection (access panels either side).
Fusible link: a heat-sensitive link (designed to melt or release at a set temperature) that holds a fire damper open and releases in a fire's heat, letting the damper close. So the fusible link is the trigger that closes the fire damper when it gets hot. You may also meet spark arrestor (a device to catch sparks/embers, relevant for solid-fuel cooking) and grease guard/grease box (grease-collection features). These safety devices (interlock, fire damper, fusible link) are part of the ventilation system's safety, and are covered more fully in the dedicated pages (fusible links, fire dampers and interlocks defined; gas interlocks). So the safety devices - interlock, fire damper, fusible link - are the terms for the ventilation system's built-in safety features. Knowing them helps you understand the safety side of your system. So interlock, fire damper and fusible link are the safety terms. This is general information.
Know the vocabulary
So that is a plain-English glossary of the main commercial kitchen ventilation terms: the parts of the system (canopy, grease filters, plenum, ductwork, riser, extract fan), the air side (extract, supply, make-up air, negative pressure), the standards and cleaning (TR19 Grease, access panels, deep clean, the reports), and the safety devices (interlock, fire damper, fusible link). Knowing these terms helps you understand your own extraction system, read a cleaning report or quote, and talk to an extraction cleaner or engineer. So know the vocabulary - understand your system and your report.
The value of the vocabulary is practical: when a cleaner talks about the plenum, the access panels, or cleaning to TR19 Grease, or a report refers to the ductwork and the extract fan, or a quote mentions make-up air or the interlock, you can follow what they mean - understanding what part of the system or what aspect they are talking about. This helps you ask the right questions, understand what a clean covers, and know your system. This glossary is a general reference for the terms; the individual pages linked cover many of them in depth (the filter types, the standard, the safety devices). So keep this glossary as a reference, and refer to the detailed pages for more. So know the vocabulary - understand your system and your report. This is general information for reference.
Questions
The canopy (or hood) is the hood mounted over the cooking line that collects the rising heat, smoke, steam and grease-laden vapour and channels it into the extraction. It is the visible top of the extraction system in the kitchen - positioned over the cooking appliances to capture what rises from them. The canopy holds the grease filters (which catch grease from the vapour) and behind them the plenum (the collecting chamber), and it connects to the ductwork that carries the air away. So the canopy is where the extraction starts: collecting the cooking's output and beginning to clean it (via the filters) before the air goes into the ductwork. It needs cleaning inside and out (grease builds up on and in it) as part of the extraction clean. So a canopy is the hood over the cooking that collects the vapour into the extraction. This is general information.
Make-up air (or replacement air) is the fresh air supplied into the kitchen to replace the air being extracted - needed to balance the ventilation system. The extraction pulls a large volume of air out of the kitchen (carrying the heat, smoke and grease), and that air has to be replaced - so make-up air is supplied in (through a supply system or ventilation) to balance what goes out. If air is extracted but not replaced, the kitchen goes into negative pressure (a partial vacuum), which starves the extraction (it can't pull air out with none coming in), makes doors hard to open, causes draughts, and can pull fumes back down flues. So make-up air keeps the system balanced and working properly. It is why extraction is part of a balanced ventilation system, not just a fan pulling air out. So make-up air is the fresh replacement air that balances the extraction. This is general information.
TR19 Grease is the recognised standard (from BESA) for cleaning commercial kitchen grease extraction systems - setting the required cleanliness, the whole-system approach, and a risk-based cleaning frequency. Published by BESA (the Building Engineering Services Association), TR19 Grease is the current specification for cleaning grease extraction ductwork: it defines how clean the system must be (measured, e.g. by grease-deposit thickness), that the whole system should be cleaned (canopy, filters, ductwork, fan), and how often (a risk-based frequency depending on how much and what kind of cooking you do). Formerly this guidance sat within the broader ductwork standard TR19; the grease-extraction part is now 'TR19 Grease'. A clean 'to TR19 Grease' means cleaned to this recognised standard, with the verification and records (report, photographs, certificate). It is the standard insurers and fire risk assessments look to. So TR19 Grease is the recognised standard for cleaning grease extraction. This is general information.
Access panels are the openings (hatches) built into the ductwork that let a cleaner reach inside to clean and inspect it - needed at intervals and key points so the whole duct can be reached. The ductwork is enclosed, so to clean the grease off its internal surfaces a cleaner needs openings to reach inside - these are the access panels. TR19 Grease expects them at suitable intervals along the duct and at key points (bends, and either side of fire dampers), so no section is unreachable. Without adequate access panels, stretches of duct can't be reached and cleaned (leaving grease-laden, uncleaned sections - a hidden fire risk). So access panels are essential to being able to clean the whole duct - the principle being 'you can't clean what you can't reach'. An under-panelled duct may need extra access panels retrofitted. So access panels are the openings that let the duct be cleaned throughout. This is general information.
A fire damper is a device in the ductwork that closes to block the spread of fire through the duct; a fusible link is the heat-sensitive trigger that holds it open and releases in a fire's heat to let it close. The fire damper is a safety barrier fitted in the duct: normally open (letting the air through), it closes if a fire occurs, helping to contain the fire and stop it spreading through the ductwork into other parts of the building. The fusible link is what triggers it: a heat-sensitive link (designed to melt or release at a set temperature) that holds the damper open in normal use and releases when it gets hot (in a fire), allowing the damper to close. So the fusible link is the automatic trigger, and the fire damper is the barrier. Both need access for cleaning and inspection (grease must not clog them). They are covered more fully in the dedicated safety-devices pages. So a fire damper blocks fire spread in the duct, and a fusible link triggers it to close. This is general information.
Because knowing the vocabulary helps you understand your own system, read a cleaning report or quote, and talk clearly with an extraction cleaner or engineer. Commercial kitchen ventilation has its own terms - canopy, plenum, ductwork, extract fan, make-up air, TR19 Grease, access panels, interlock - and they come up when you deal with your extraction: in a cleaner's explanation, a cleaning report, a quote, or an engineer's advice. If you know what the terms mean, you can follow what is being said (what part of the system, what aspect, what standard), ask the right questions, understand what a clean covers and to what standard, and know your own system better. So the vocabulary is practically useful - it lets you engage with your extraction knowledgeably rather than being baffled by jargon. This glossary is a reference for the terms, with detailed pages on many of them. So knowing the terms helps you understand and manage your extraction. This is general information.
Canopy, filters, plenum, ductwork, extract fan, make-up air, TR19 Grease - we clean the whole grease extraction system to the recognised standard, and can explain the terms and what a clean covers so you understand your system and your report. Ask us about your extraction cleaning. This is general information for reference.
