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Kitchen extraction cleaning - specifying a system
Specifying a commercial extraction system from scratch is where a kitchen's ventilation is made or broken - get it right and it performs and lasts; get it wrong and you live with a poor, hard-to-clean system for years. It means matching every element to your cooking, and designing in cleanability. Here is what specifying an extraction system involves, in outline. This is general information; system specification is for a competent designer.
The short answer
The extraction system is one of the most important - and most permanent - parts of a commercial kitchen, and how it's specified from scratch determines whether it performs, lasts and can be kept clean for years, or becomes a costly, hard-to-maintain liability. Here, in outline, is what specifying an extraction system involves. This is general information; the actual specification is a job for a competent ventilation designer. Start from the cooking. Everything in the specification flows from the cooking: the type and volume of cooking (the appliances - ranges, fryers, chargrills, woks, solid-fuel - and how heavily used) determine the heat, smoke and grease the system must handle, and so the demands on every element. So the spec starts by understanding the cooking, and matches the system to it. The elements to specify. (1) The canopy. The type (wall, island, and so on), size and position - to cover the cooking appliances and capture the rising plume effectively (with proper overhang and height, as covered in positioning a canopy). (2) The airflow. The extraction rate - the volume of air the system must move to clear the cooking's output - driven by the canopy and cooking load. (3) The fan. Sized to deliver the required airflow against the system's resistance (the ductwork, filters, dampers), as covered in how extractor fans are sized. (4) The ductwork. Routed sensibly through the building, sized (to carry the airflow at suitable velocity), and made of suitable material (as covered in choosing ductwork material). (5) The make-up air. Balanced to the extraction (to replace what's removed), well-distributed (not disrupting the canopies), and ideally tempered - so the system is balanced and the kitchen comfortable (as covered in make-up air design). All these elements must be specified to match the cooking and to work together as one balanced system. Design in access and cleanability. Crucially - and often neglected in specifications focused only on performance - the access and cleanability must be designed in from the start: adequate access panels throughout the ductwork (so the whole duct can be cleaned to TR19 Grease - no unreachable stretches); a fan that can be safely reached and serviced; and sensible routing (avoiding convoluted, inaccessible runs). This is essential because the system will need regular cleaning (for fire safety) for its whole life - a system that can't be cleaned is a standing fire risk. So the spec must design for maintenance, not just day-one performance. The result of a good spec. A well-specified extraction system performs (effective, balanced ventilation for the cooking), lasts (robust and well-matched, not overwhelmed or oversized), and can be kept clean (good access, so the fire risk is controllable) - serving the kitchen well for years. A poorly-specified one (wrong size, poor routing, no cleaning access) performs badly and becomes a maintenance and fire-safety headache. So spec a commercial extraction system from scratch by matching the canopy, airflow, ductwork, fan and make-up air to your cooking, and designing in the access and cleanability - a specialist job for a competent designer. So specify to perform, last and be cleanable. This is general information; specification is for a competent designer.
Key points
Start from the cooking
Specifying an extraction system starts from the cooking, because the cooking sets the demands on every element of the system. The type and volume of cooking - what appliances the kitchen uses (ranges, fryers, chargrills, woks, solid-fuel cooking) and how heavily they're used - determine how much heat, smoke, steam and grease-laden vapour the system must handle. Heavy, greasy or solid-fuel cooking makes far greater demands (more heat and grease to clear, more robust handling needed) than light cooking.
So the specification begins by understanding the cooking, and then matches the system to it: the canopy sized and positioned for the appliances, the airflow set to clear the cooking's output, the fan sized accordingly, the ductwork and make-up air to suit, and the whole robust enough for the grease load. Everything follows from the cooking. This is why a spec can't be generic or copied - it must be based on the actual cooking the kitchen will do (its menu, appliances and volume). Getting this foundation right (understanding and specifying for the real cooking) is essential; a system specified for the wrong cooking (too light, or generic) will be wrong. So start from the cooking - the cooking sets every demand. The elements, matched to the cooking, follow. So the cooking sets every demand on the system. This is general information.
Size the canopy, airflow and fan
The core of the extraction specification is sizing the canopy, the airflow and the fan - the heart of the system - to match the cooking load. The canopy: specify the type (wall-mounted, island, and so on), size and position to cover the cooking appliances and capture the rising plume effectively - sized to the cooking line, with proper overhang and mounted at the right height (as covered in positioning a canopy for capture). The canopy is where the extraction captures the plume, so getting it right is fundamental.
The airflow: specify the extraction rate - the volume of air the system must move to clear the cooking's heat, smoke and grease - which is driven by the canopy and the cooking load (design guidance sets how much airflow the canopy and cooking need). The fan: specify a fan sized to deliver that required airflow against the system's resistance (from the ductwork, filters and dampers) - so it actually moves the needed air through the real system (as covered in how extractor fans are sized). These three - canopy, airflow, fan - are the heart of the system, and must be sized together and matched to the cooking load (not under-sized, which fails to clear the kitchen, nor grossly over-sized, which wastes energy and unbalances the air). So size the canopy, airflow and fan - the heart of the system, matched to the load. The ductwork and make-up air complete it. So size the core elements to the cooking. This is general information; sizing is for a competent designer.
Specify the ductwork and make-up air
The specification is completed by the ductwork and the make-up air - the elements that carry the air and balance the system. The ductwork: specify it routed sensibly through the building (as direct and accessible as practical, avoiding needlessly long or convoluted runs), sized to carry the airflow at a suitable velocity (not too small, which raises resistance, nor too large), and made of suitable material for a grease extraction duct (as covered in choosing ductwork material). The ductwork carries the extracted air from the canopy to discharge, so its routing, size and material matter for performance, longevity and cleanability.
The make-up air: specify it balanced to the extraction (supplying to replace what the extraction removes, so the system is balanced), well-distributed (introduced so it reaches the kitchen without disrupting the canopies' capture), and ideally tempered (heated in winter, not excessively hot in summer, for comfort) - as covered in make-up air design. The make-up air is integral - the extraction can't work properly without it, and the two must be specified together as a balanced system. So specifying the ductwork (carrying the air) and the make-up air (balancing the system) completes the extraction specification - the whole system, all elements matched to the cooking and to each other. So specify the ductwork and make-up air - completing the balanced system. But one more thing, often neglected, must be in the spec: access and cleanability. So complete the system with ductwork and make-up air. This is general information; the design is for a competent designer.
Design in access and cleanability
The most often-neglected but essential part of specifying an extraction system is designing in the access and cleanability - because the system will need cleaning for its whole life, and a spec focused only on day-one performance produces a fire-safety liability. The system accumulates grease and must be cleaned regularly (to TR19 Grease, at a frequency matched to the cooking) to control the fire risk, for as long as the kitchen operates. So the specification must make that cleaning possible and practical, by designing in: adequate access panels throughout the ductwork (so the whole duct can be reached and cleaned - no hidden, unreachable stretches); a fan that can be safely reached and serviced; and sensible routing (avoiding convoluted, inaccessible runs that are hard to clean).
This is not optional or secondary - it's essential, because a system that can't be properly cleaned is a standing fire risk (grease building up uncleaned where it can't be reached). A specification that sizes everything perfectly for performance but neglects cleaning access produces a system that works on day one but can't be safely maintained - a costly mistake that's hard to fix later (retrofitting access is imperfect). So the spec must design for the whole life of the system: performance and cleanability together. This is covered further in briefing a ventilation designer and designing for maintenance access. So design in access and cleanability - specify for the whole life, not just day one. This is arguably the most important thing to get into the spec, given the fire risk. So specify for cleanability and the whole life. This is general information; the design is for a competent designer.
A system that performs and lasts
So specifying a commercial extraction system from scratch means designing all its elements - the canopy, airflow, fan, ductwork and make-up air - to match your cooking and work together as a balanced system, and designing in the access and cleanability it needs for its whole life. Done well, the result is a system that performs (effective, balanced ventilation for the cooking), lasts (robust and well-matched), and can be kept clean (the fire risk controllable) - serving the kitchen well for years. So a system that performs and lasts: matched to the cooking, cleanable for life.
The stakes of getting the spec right are high, because the extraction is permanent and costly - a well-specified system serves the kitchen for years, while a poorly-specified one (wrong size, poor routing, no cleaning access) performs badly, is a headache to maintain, and can't control its fire risk - problems you live with or pay dearly to fix. So the specification deserves proper care and expertise: it's a specialist job for a competent ventilation designer, who can size and design the elements correctly, match them to the cooking, balance the system, and - crucially - design in the cleanability. Understanding the principles (match to the cooking, design in cleanability) helps you brief and engage them (as in briefing a ventilation designer). So spec a commercial extraction system from scratch to perform, last and be cleanable - matched to the cooking, cleanable for life, specified by a competent designer. So specify for performance, longevity and cleanability. This is general information; system specification is for a competent designer.
Questions
Designing all its elements - canopy, airflow, fan, ductwork and make-up air - to match your cooking and work as a balanced system, and designing in the access and cleanability for its whole life. Specifying an extraction system from scratch starts from the cooking (type and volume, which set the demands) and matches every element to it: the canopy (type, size, position - to capture the plume); the airflow (the extraction rate to clear the cooking's output); the fan (sized to deliver that airflow against the system's resistance); the ductwork (routed, sized and made of suitable material); and the make-up air (balanced, distributed, tempered). All must work together as one balanced system. And crucially, the access and cleanability must be designed in (adequate access panels, a reachable fan, sensible routing) so the system can be cleaned to TR19 Grease for its whole life. It's a specialist job for a competent designer. So it involves matching the elements to the cooking and designing in cleanability. So specify the elements to the cooking, with cleanability. This is general information; specification is for a competent designer.
The cooking - the type and volume of cooking sets how much heat, smoke and grease the system must handle, which drives the canopy size, the airflow, the fan and the rest. Everything in the specification flows from the cooking. The appliances the kitchen uses (ranges, fryers, chargrills, woks, solid-fuel) and how heavily they're used determine the heat, smoke and grease-laden vapour the system must clear - and so the demands on every element: the canopy sized to cover and capture the plume, the airflow set to clear the output, the fan sized to deliver it, and the ductwork and make-up air to suit. Heavy, greasy or solid-fuel cooking demands a bigger, more robust system than light cooking. So the cooking is what sizes the system - which is why the spec must be based on the actual cooking, not generic. So the cooking (type and volume) determines the system's size. So the cooking load sizes it. This is general information; sizing is for a competent designer.
Because the system needs regular cleaning for fire safety for its whole life - so it must have adequate access panels, a reachable fan and sensible routing; a system that can't be cleaned is a standing fire risk. The extraction accumulates grease continuously and must be cleaned (to TR19 Grease, at a frequency matched to the cooking) to control the fire risk, for as long as the kitchen operates. So the specification must make that cleaning possible: adequate access panels throughout the ductwork (so the whole duct can be reached - no hidden stretches), a fan that can be safely reached and serviced, and sensible routing. This is essential, not optional - a system specified for day-one performance but with no cleaning access can't be safely maintained (grease builds up uncleaned where it can't be reached - a fire risk), and it's hard to fix later. So cleanability must be designed into the spec from the start, alongside performance. So it must be designed in because the system needs cleaning for life and uncleanable extraction is dangerous. So because it needs cleaning for its whole life. This is general information.
Sizing is part of specifying - specifying is the whole design of the system (all elements, matched to the cooking, plus cleanability), while sizing is determining the right dimensions/capacities (of the canopy, airflow, fan, ductwork). Specifying an extraction system is the complete design task: choosing and designing all the elements (canopy, airflow, fan, ductwork, make-up air), matching them to the cooking, ensuring they work together as a balanced system, and designing in the access and cleanability. Sizing is one aspect of that - determining the right dimensions and capacities: how big the canopy, how much airflow, what fan capacity, what duct size. So sizing is a key part of specifying (getting the quantities right), while specifying is the whole design (including the elements, their integration, the routing, the make-up air, and the cleanability). Both are needed, and both are for a competent designer. So sizing is part of the wider task of specifying. So sizing is one part of specifying. This is general information.
No - the spec must match your specific cooking, kitchen and building, which differ from another's; a copied spec risks a system wrong for your kitchen. It's tempting to copy a spec, but an extraction system must be specified for the specific kitchen: your cooking (type and volume) sets the demands, and your building (layout, routes, constraints) shapes the design - and these differ from another kitchen's. A spec copied from a kitchen with different cooking or a different building could be wrong for yours (under- or over-sized, poorly routed, wrong make-up air). So the specification should be done for your kitchen, based on your actual cooking and building - not copied. This is one reason it's a job for a competent designer, who specifies for your specific situation. Understanding the principles helps you engage them, but the spec itself must be yours. So no - specify for your own kitchen, not by copying. So no - it must match your specifics. This is general information.
A competent ventilation designer - specifying an extraction system (sizing, routing, balancing, and designing in cleanability) is a specialist task, not something to guess or copy. Specifying a commercial extraction system well - sizing the canopy, airflow and fan to the cooking, routing and sizing the ductwork, balancing the make-up air, and designing in the access and cleanability - is a specialist ventilation design task requiring proper expertise. So it should be done by a competent ventilation designer (or ventilation engineer), who can do the calculations, match the system to your cooking and building, ensure it's balanced, and design it to be cleanable and maintainable. Understanding the principles (match to the cooking, design in cleanability) helps you brief and engage them (as in briefing a ventilation designer), but the specification itself should be professional. Getting it wrong is costly and hard to fix. So a competent ventilation designer should specify it. So a competent designer. This is general information; specification is for a competent designer.
A system specified with the access and cleanability it needs - adequate panels, a reachable fan, sensible routing - can be kept clean to TR19 Grease for its whole life. We clean such systems thoroughly, and a good specification is what makes that possible. Ask us about keeping your extraction clean, whatever its spec. This is general information; system specification is for a competent designer.
