7 Proven Commercial Kitchen Ductwork & Airflow Design Secrets Every Restaurant Owner Should Know
7 Proven Commercial Kitchen Ductwork & Airflow Design Secrets Every Restaurant Owner Should Know
Walk into any professional kitchen during a busy service and you’ll feel it immediately: heat, steam, grease-laden air, and the constant hum of extraction fans working to keep the space breathable. Most of that performance or lack of it comes down to one thing hiding above the ceiling tiles: the commercial kitchen ductwork systems.
Get it right, and your kitchen stays cool, compliant, and efficient. Get it wrong, and you’re looking at grease fires, failed inspections, soaring energy bills, and a chef’s team working in an oven. This guide breaks down exactly how commercial kitchen ductwork systems and airflow design work, the mistakes most UK restaurants make, and what proper compliance actually looks like.
What Are Commercial Kitchen Ductwork Systems?
A commercial kitchen ductwork system is the network of extraction and supply ducting that removes heat, grease, steam, and odours from a kitchen while replacing that air with clean, tempered air from outside. It typically includes:
Extraction canopies positioned over cooking equipment to capture grease-laden effluent at source
Grease ductwork welded, fire-rated ducting that carries extracted air safely to roof-level discharge
Extract fans, often EC (electronically commutated) for efficiency
Make-up air systems that replace extracted air, preventing negative pressure in the kitchen
Fire dampers and access panels for safety and cleaning compliance
Why Airflow Design Matters in Commercial Kitchens?
Airflow design isn’t just about pulling smoke out of the room it’s a calculation. Extraction rates need to match the heat and grease load produced by the equipment beneath the canopy, and the make-up air supplied needs to roughly balance what’s being extracted.
Poorly designed airflow causes a cascade of problems:
Negative pressure, which pulls in cold air through doors and makes gas appliances harder to light safely
Excess grease deposit in ductwork, raising fire risk
Uneven kitchen temperatures, with hot spots near the pass and cold draughts near entrances
Higher energy bills, from fans working harder than necessary or oversized systems running inefficiently
A correctly designed system calculates extraction volume (in litres per second) based on canopy size, equipment type, and cooking method, then balances it with tempered or untempered make-up air, depending on the kitchen’s size and layout.
How Commercial Kitchen Ductwork systems and Canopy Installation Works
Canopy installation typically follows a defined project sequence:
Site survey — measuring the kitchen, assessing equipment loads, and identifying duct routing options
Design and airflow calculation — sizing the canopy, ductwork diameter, and fan specification to DW172 standards
Fabrication — stainless steel canopies and ductwork are typically built off-site or on-site to exact dimensions
Installation — canopy hung, ductwork routed and sealed, fans and controls fitted
Commissioning — airflow rates tested and balanced against the original design figures
Handover — documentation provided for Building Control and insurance purposes, along with a maintenance schedule
Minimising restaurant downtime is a major factor here. Most reputable contractors plan canopy and ductwork installation around a kitchen’s closed days or overnight windows, sequencing fabrication off-site so on-site disruption is kept as short as possible.
7 Common Ductwork Design Mistakes to Avoid
Undersized ductwork — restricts airflow, forces fans to work harder, and increases noise and energy use
Poor duct routing — excessive bends reduce airflow efficiency and make TR19 cleaning far harder
No make-up air provision — creates negative pressure, door-slamming draughts, and pilot light issues
Non-fire-rated ductwork near escape routes — a serious compliance and safety failure
Ignoring noise levels — oversized fans without acoustic attenuation cause noise complaints, especially in mixed-use buildings
Skipping access panels — makes TR19 grease duct cleaning impossible without cutting into ductwork later
Treating extraction as an afterthought — bolting a system onto a finished kitchen design, rather than designing airflow alongside the kitchen layout from day one
Material choice affects fire safety, longevity, and maintenance cost. The two most common options are galvanised steel and stainless steel ductwork.
Feature
Standard Ductwork
Professionally Designed Commercial Kitchen Ductwork Systems
Airflow Efficiency
Low
High
Grease Build-up
High
Minimal
Fire Safety
Basic
DW172-Compliant
Energy Consumption
Higher
Lower
Maintenance
Frequent
Easier
Kitchen Comfort
Poor
Improved
Compliance
May Fail
Meets UK Standards
Stainless steel is generally specified for ductwork closest to the cooking line, where grease and heat exposure is highest, while galvanised steel is often used for lower-risk supply ductwork. A professionally designed commercial kitchen ductwork systems accounts for this material split from the outset rather than defaulting to the cheapest option throughout.
DW172 & TR19 Compliance Explained Two standards dominate UK kitchen extraction compliance:
DW172 (“Specification for Kitchen Ventilation Systems”) sets out design and installation requirements for canopies, ductwork construction, fire dampers, and access provision. It’s the reference point most insurers and Building Control officers check against.
TR19 Grease covers the ongoing cleanliness of grease extraction ductwork, setting out inspection frequency and cleanliness standards to reduce fire risk from accumulated grease.
Alongside these, kitchens also need to consider Building Control sign-off for structural and fire safety elements, and where gas appliances are involved coordination with a Gas Safe registered engineer. A typical compliance timeline runs: design to DW172 → installation → commissioning and airflow testing → Building Control notification → ongoing TR19 cleaning schedule (commonly every 3–12 months depending on cooking volume).
Airflow Design Process Step-by-Step
Assess equipment heat and grease load for every appliance under the canopy
Calculate required extraction rate in litres per second, per DW172 guidance
Size the canopy and ductwork to carry that volume without excessive velocity or noise
Calculate make-up air requirements, typically 85–90% of extract volume, to maintain slight negative pressure without starving the kitchen of air
Select fan specification, increasingly EC fan technology for energy savings and variable-speed control
Plan duct routing for the shortest, straightest path to discharge, minimising bends
Commission and balance the system, testing actual airflow against design figures
Frequently Asked Questions
How often does commercial kitchen ductwork systems need cleaning?
Under TR19 guidance, cleaning frequency depends on cooking volume heavy-use kitchens may need cleaning every 3 months, while lower-use kitchens may only need annual cleaning.
What’s the difference between DW172 and TR19?
DW172 governs design and installation of the extraction system; TR19 governs the ongoing cleanliness and inspection of grease ductwork once it’s in use.
Do I need make-up air in a small commercial kitchen ductwork systems?
Most kitchens do. Without it, extraction fans can pull air from other parts of the building, causing draughts, door problems, and inefficient gas combustion.
Can existing ductwork be upgraded instead of replaced?
Sometimes it depends on the condition, sizing, and fire rating of the existing system. A site survey will confirm whether an upgrade or full replacement is the better route.
How long does a commercial kitchen canopy installation take?
This varies with kitchen size and complexity, but off-site fabrication and careful scheduling around kitchen closing hours can keep on-site disruption to a minimum.
Why Choose Brightwork Builders?
Brightwork Builders designs and installs commercial kitchen ductwork systems and canopy to DW172 standards across the UK, working with restaurants, takeaways, cafés, and commercial kitchens from initial survey through to commissioning and handover. Our commercial kitchen canopy installation and commercial kitchen extraction systems services are built around minimising kitchen downtime and getting airflow design right the first time.
If you’re planning a restaurant refurbishment or need a commercial kitchen ductwork systems installation that will pass Building Control and keep your kitchen compliant for years to come, our commercial kitchen ventilation team can help. Get in touch for a site survey, or read more about Brightwork Builders.
7 Proven Commercial Kitchen Ductwork & Airflow Design Secrets Every Restaurant Owner Should Know
Walk into any professional kitchen during a busy service and you’ll feel it immediately: heat, steam, grease-laden air, and the constant hum of extraction fans working to keep the space breathable. Most of that performance or lack of it comes down to one thing hiding above the ceiling tiles: the commercial kitchen ductwork systems.
Get it right, and your kitchen stays cool, compliant, and efficient. Get it wrong, and you’re looking at grease fires, failed inspections, soaring energy bills, and a chef’s team working in an oven. This guide breaks down exactly how commercial kitchen ductwork systems and airflow design work, the mistakes most UK restaurants make, and what proper compliance actually looks like.
What Are Commercial Kitchen Ductwork Systems?
A commercial kitchen ductwork system is the network of extraction and supply ducting that removes heat, grease, steam, and odours from a kitchen while replacing that air with clean, tempered air from outside. It typically includes:
The system as a whole is what UK regulation refers to when it discusses kitchen extraction, and it’s governed primarily by two industry standards: DW172 (design and installation) and TR19 (grease duct cleanliness and maintenance).
Why Airflow Design Matters in Commercial Kitchens?
Airflow design isn’t just about pulling smoke out of the room it’s a calculation. Extraction rates need to match the heat and grease load produced by the equipment beneath the canopy, and the make-up air supplied needs to roughly balance what’s being extracted.
Poorly designed airflow causes a cascade of problems:
A correctly designed system calculates extraction volume (in litres per second) based on canopy size, equipment type, and cooking method, then balances it with tempered or untempered make-up air, depending on the kitchen’s size and layout.
How Commercial Kitchen Ductwork systems and Canopy Installation Works
Canopy installation typically follows a defined project sequence:
Site survey — measuring the kitchen, assessing equipment loads, and identifying duct routing options
Design and airflow calculation — sizing the canopy, ductwork diameter, and fan specification to DW172 standards
Fabrication — stainless steel canopies and ductwork are typically built off-site or on-site to exact dimensions
Installation — canopy hung, ductwork routed and sealed, fans and controls fitted
Commissioning — airflow rates tested and balanced against the original design figures
Handover — documentation provided for Building Control and insurance purposes, along with a maintenance schedule
Minimising restaurant downtime is a major factor here. Most reputable contractors plan canopy and ductwork installation around a kitchen’s closed days or overnight windows, sequencing fabrication off-site so on-site disruption is kept as short as possible.
7 Common Ductwork Design Mistakes to Avoid
Commercial Kitchen Ductwork Systems Materials Compared
Material choice affects fire safety, longevity, and maintenance cost. The two most common options are galvanised steel and stainless steel ductwork.
Feature
Standard Ductwork
Professionally Designed Commercial Kitchen Ductwork Systems
Airflow Efficiency
High
High
Minimal
Basic
Energy Consumption
Higher
Lower
Maintenance
Frequent
Easier
Improved
Compliance
May Fail
Meets UK Standards
Stainless steel is generally specified for ductwork closest to the cooking line, where grease and heat exposure is highest, while galvanised steel is often used for lower-risk supply ductwork. A professionally designed commercial kitchen ductwork systems accounts for this material split from the outset rather than defaulting to the cheapest option throughout.
DW172 & TR19 Compliance Explained
Two standards dominate UK kitchen extraction compliance:
Alongside these, kitchens also need to consider Building Control sign-off for structural and fire safety elements, and where gas appliances are involved coordination with a Gas Safe registered engineer. A typical compliance timeline runs: design to DW172 → installation → commissioning and airflow testing → Building Control notification → ongoing TR19 cleaning schedule (commonly every 3–12 months depending on cooking volume).
Airflow Design Process Step-by-Step
Frequently Asked Questions
How often does commercial kitchen ductwork systems need cleaning?
Under TR19 guidance, cleaning frequency depends on cooking volume heavy-use kitchens may need cleaning every 3 months, while lower-use kitchens may only need annual cleaning.
What’s the difference between DW172 and TR19?
DW172 governs design and installation of the extraction system; TR19 governs the ongoing cleanliness and inspection of grease ductwork once it’s in use.
Do I need make-up air in a small commercial kitchen ductwork systems?
Most kitchens do. Without it, extraction fans can pull air from other parts of the building, causing draughts, door problems, and inefficient gas combustion.
Can existing ductwork be upgraded instead of replaced?
Sometimes it depends on the condition, sizing, and fire rating of the existing system. A site survey will confirm whether an upgrade or full replacement is the better route.
How long does a commercial kitchen canopy installation take?
This varies with kitchen size and complexity, but off-site fabrication and careful scheduling around kitchen closing hours can keep on-site disruption to a minimum.
Why Choose Brightwork Builders?
Brightwork Builders designs and installs commercial kitchen ductwork systems and canopy to DW172 standards across the UK, working with restaurants, takeaways, cafés, and commercial kitchens from initial survey through to commissioning and handover. Our commercial kitchen canopy installation and commercial kitchen extraction systems services are built around minimising kitchen downtime and getting airflow design right the first time.
If you’re planning a restaurant refurbishment or need a commercial kitchen ductwork systems installation that will pass Building Control and keep your kitchen compliant for years to come, our commercial kitchen ventilation team can help. Get in touch for a site survey, or read more about Brightwork Builders.