Regulatory requirements for smoke extraction in kitchens

Do you know the requirements of the current regulations regarding smoke extraction in kitchens? In this article, we summarize the regulatory requirements of the Technical Building Code.

Minimum ventilation flows

With the recent modification of the CTE DB HS 3 Indoor air quality, the Technical Code no longer distinguishes between kitchens, bathrooms, toilets, and laundry rooms. It encompasses all these rooms under the joint classification of "wet rooms". The Basic Document establishes two flows: "minimum total" and "minimum per room". To establish the flow, it makes a distinction based on the number of bedrooms in the home:

• In homes with 0 or 1 bedroom, the minimum total is 12 l/s and the minimum per room is 6 l/s.
• For homes with 2 bedrooms, the first parameter is 24 l/s and the second, 7 l/s.
• In homes with 3 or more bedrooms, the first flow is 33 l/s and the second, 8 l/s.

Since the drafting of the first version of the CTE, the need to implement a specific mechanical extraction ventilation system in kitchens has already been stipulated. With this recent modification, it is also determined that this mechanical extraction system must ensure a minimum extraction flow of 50 l/s.

Smoke extraction in kitchens: requirements

In the case of professional kitchens, the CTE DB SI Fire safety categorizes a restaurant kitchen as a space with a high fire risk, as a gas kitchen with 6 burners can exceed 50 kW.

The requirements set by the CTE are as follows:

Extraction outlets

Extraction outlets should be located on the roof, at least 3 meters away from any air supply element for ventilation. They should also be separated from any room where people gather.

Extraction ducts

• The smoke extraction ducts must have a uniform section, be free of obstacles inside, and have a smooth finish that prevents contamination.
• Smoke extraction will be individual for each appliance and for each kitchen.
• If the ducts run through the interior of the building or through the exterior envelope at a distance not exceeding 1.50 meters from areas of the facade classified as EI 30 or at a distance not exceeding 1.50 meters from balconies, terraces, or openings, these must have an EI 30 classification.
• Fire dampers inside smoke extraction ducts are strictly prohibited.
• The smoke extraction system must be accessible for maintenance and cleaning. In horizontal branches, access should be provided every three meters or less.

Extractor hoods

• Any smoke extraction hood must be installed at least half a meter away from any material not classified as A1 (non-combustible).
• In the case of gas kitchens or grills, the filters of the extraction hoods must be at least 1.20 meters away from heat sources. For other cooking appliances, the distance cannot be less than half a meter.
• Extraction hoods must be removable to facilitate cleaning.

Fans

The fire classification of the fans must be F400 90 and comply with the specifications of standard UNE-EN 12101-3: 2002 "Specifications for mechanical smoke and heat extractors."