Deep Dive Guide into Extraction Canopy Regulations
In the world of commercial kitchens, maintaining a safe and efficient cooking environment is non-negotiable. One of the most critical elements of kitchen ventilation systems is the extraction canopy (also known as the hood). The extraction canopy is responsible for capturing and containing grease, heat, smoke, and fumes, ensuring they are safely removed from the kitchen. To comply with UK regulations, particularly DW172: Specification for Kitchen Ventilation Systems, proper design, installation, and maintenance of extraction canopies are essential.
This blog post will guide you through the specific requirements for extraction canopies under DW172, helping you create a compliant and efficient kitchen environment.
What Is DW172?
DW172 is the industry standard published by the Building Engineering Services Association (BESA) for designing and installing commercial kitchen ventilation systems. It outlines detailed specifications for various components, including extraction canopies, ductwork, fans, and make-up air systems, ensuring safety, efficiency, and compliance with regulatory standards.
Key Requirements to comply with Extraction Canopy Regulations in DW172
1. Extraction Canopy Sizing and Coverage
- The canopy must extend at least 300mm beyond the front and sides of all cooking equipment.
- For island configurations, the canopy must provide full coverage on all sides.
- Overhang ensures effective capture of rising heat, grease, and fumes before they escape into the kitchen.
2. Canopy Design
- Canopies must be designed to capture and contain emissions effectively:
- Wall-Mounted Canopies: Used for cooking appliances against walls, typically sloped or boxed in shape.
- Island Canopies: For freestanding equipment in the centre of the kitchen, often requiring a larger coverage area.
- Incorporate angled baffle filters to trap grease and allow easy cleaning.
- Provide appropriate lighting within the canopy using sealed, fire-rated fixtures.
3. Minimum Airflow Rates
- DW172 specifies airflow rates based on the type of equipment beneath the canopy:
- Light-duty appliances (e.g., steamers): 0.25 m³/s per linear meter of canopy.
- Medium-duty appliances (e.g., griddles): 0.35 m³/s per linear meter.
- Heavy-duty appliances (e.g., fryers, charbroilers): 0.5 m³/s per linear meter.
- Extra heavy-duty appliances (e.g., solid fuel grills): 0.6 m³/s or higher.
- These rates ensure sufficient extraction to remove heat and fumes efficiently.
4. Grease Filtration
- Canopies must include baffle grease filters or other compliant filters with a minimum efficiency of 90%.
- Filters should be installed at an angle between 45 and 60 degrees to optimize airflow and grease collection.
- Ensure filters are removable for regular cleaning and maintenance.
5. Materials and Construction
- Canopies must be constructed from stainless steel or equivalent fire-resistant materials.
- The joints and seams must be fully welded or sealed to prevent grease accumulation.
- The canopy should have a minimum thickness of 1mm for durability and safety.
6. Canopy Height and Placement
- The bottom of the canopy should be installed at a height of ideally, 2,000mm / 2m above the finished floor level, depending on the type of equipment and local guidelines.
- This height ensures effective capture of heat and fumes while allowing safe operation by staff.
7. Integrated Fire Safety Features
- Canopies should be designed to accommodate fire suppression systems if required by local fire codes.
- Install nozzles or sprinklers to extinguish grease fires directly within the canopy.
8. Supply and Make-Up Air
- Ensure proper integration with a make-up air system to replace the air extracted by the canopy.
- Supply air should be evenly distributed to avoid creating negative pressure in the kitchen.
- DW172 recommends providing make-up air equal to 85-90% of the extracted air volume.
- Supply air doesn’t have to be integral to the extraction canopy units design but can be via external supply ductwork
9. Maintenance and Access
- Include access panels for cleaning grease ducts and inspecting the canopy.
- Canopies and grease filters must be cleaned regularly, with cleaning frequency determined by kitchen usage:
- High-use kitchens: Weekly cleaning.
- Moderate-use kitchens: Monthly
10. Installation / Fixing Notes
- When installing an extraction canopy hood the building fabric must be surveyed and understood. There are various ways of installing a stainless canopy to the building. When hanging from a high ceiling you can use threaded rod with plate washers and M10 nuts. When fixing into the wall you are able to fix with screws in various positions depending what the building fabricate allows.
- When fixing into the building fabric you must drill through the canopy to make sure the fixings are being fitted in the correct place. Often canopies come with pre fabricated fixing points which are fine for many installations but sometimes a requirement for more specific fixing areas is needed.
Benefits of Complying with DW172 Extraction Canopy Regulations
- Improved Safety: Effective grease and heat removal minimises fire risks and ensures better air quality for kitchen staff.
- Regulatory Compliance: Adhering to DW172 avoids fines, legal issues, and potential kitchen shutdowns.
- Operational Efficiency: Proper canopy design and placement enhance the performance of the entire ventilation system.
- Reduced Maintenance Costs: Like a lot of commercial catering spares & parts, extraction canopy / vent systems can be costly. Well-maintained systems prevent grease buildup and extend the lifespan of equipment.
Extraction canopies play a critical role in commercial kitchen ventilation, and compliance with DW172 ensures your system operates safely and efficiently. From proper sizing and airflow rates to grease filtration and fire safety, following these guidelines will help you create a safe and compliant cooking environment.
If you’re planning a new kitchen or upgrading your existing system, consult with ventilation experts who specialise in DW172 compliance. They can design, install, and maintain a system tailored to your needs, ensuring your kitchen meets regulatory standards while operating at peak efficiency.
Further reading on ventilation in catering establishments.
