Requirements for kitchen extractor: regulations and sizing

Do you know what requirements the kitchen extractor in your home must meet? According to current regulations, the CTE DB HS 3, Quality of Indoor Air, the space in our home designated for cooking must have a special ventilation system to extract the vapors and contaminated air that are generated as a result of cooking food. For this purpose, an extractor must be installed that connects to an extraction tube distinct from the general ventilation system of the rest of the house. In the event that this tube is collective (i.e., serves more than one kitchen in the building and is shared with other extractors), each extractor must incorporate an automatic valve, or another backdraft prevention device, that allows connection to the tube only when this specific ventilation system is operating.

Specifications for the kitchen extractor

A good system for extracting vapors and contaminated gases from kitchens must meet the following specifications:

• It must be constructed with fireproof and self-extinguishing material.

• It must withstand temperatures up to 80ºC.

• It must ensure a ventilation flow rate ranging from 250 to 1250 m3/h.

• It must be easy and quick to assemble.

• It must be airtight.

• Its assembly must be modular, to avoid the use of silicones and adhesives. The system must be completely smooth and its section homogeneous. This way, a constant extraction volume is guaranteed and turbulence and backflows are avoided.

• It must guarantee high ventilation performance, with extraction above 90%.

Relationship between duct and ventilation flow rate

According to the standard UNE-EN 61591, Kitchen Hoods for Domestic Use. Measurement Methods of Suitability for Function, the relationship between the diameter of the suction tube and the ventilation flow rate should be as follows:

• For motors for flow rates between 300 and 550 m3/h, the diameter must not be less than 120 mm.

• For flow rates between 550 and 650 m3/h, it must not be less than 125 mm.

• For flow rates above 650 m3/h, the diameter of the suction tube must not be less than 150 mm. In the case of rectangular tubes, the relationship established by the standard is as follows:

• For motors for flow rates between 300 and 550 m3/h, the duct section must be, at a minimum, 75 × 150 mm.

• For flow rates between 550 and 650 m3/h, the duct section must be, at a minimum, 55 × 220 mm.

• For flow rates above 650 m3/h, the duct section must be, at a minimum, 90 × 180 mm.

The importance of the extractor in your kitchen

Remember that a proper installation of the kitchen extractor in your home must address two essential points. First, the aesthetic aspect that this element represents in the kitchen space cannot be overlooked. Therefore, its appearance, shape, and location must be considered. Second, we must ensure that we install those that guarantee the necessary ventilation flow rate to eliminate the steam and contaminated gases generated by the cooking activity itself.