Ventilation Shunt: Regulatory Requirements

Do you know the requirements of Spanish building regulations regarding ventilation shunts? Below, we summarize the impact of the main regulations that govern building in Spain regarding this element, the shunt.

According to the CTE DB HS 3, Indoor Air Quality, buildings must have sufficient means to eliminate contaminated air resulting from their normal and usual operation. To achieve this, a sufficient flow of outdoor air must be provided to ensure the extraction and expulsion of stale air caused by pollutants.

Shunt for Hybrid Ventilation and Mechanical Ventilation

The Technical Building Code (CTE) establishes that homes must have a general ventilation system (hybrid or mechanical). The characteristics of the ducts will depend on the type of ventilation.

Characteristics of Extraction Ducts for Hybrid Ventilation

• Each extraction duct in the building will have a hybrid extractor located just after the last extraction opening in the direction of the airflow.

• The ducts will be vertical.

• In the case of collective ducts, they must not serve more than six floors. The ducts of the last two floors must be individual. The connection of the extraction openings to the collective ducts will be made via vertical branches, each of which will lead to the duct immediately below the next branch.

• The ducts must have a uniform section and also be free of obstacles throughout their length.

• In case ducts pass through fire sector separating elements, these will comply with the fire resistance conditions established in section 3 of the SI1 section of CTE DB SI, Fire Safety.

• The ducts must have a finish that makes it difficult for them to become dirty. Additionally, they must allow for maintenance and cleaning at the top, making them accessible.

• The ducts must be airtight for their design pressure.

Extraction Ducts for Mechanical Ventilation

• Each extraction duct must have a mechanical extractor located after the last extraction opening in the direction of the airflow, except for specific kitchen ventilation. Multiple ducts may share the same extractor, except in the case of garage ducts, if more than one network is required.

• The section of each stretch of duct between two consecutive points with air supply or output must be uniform.

• The ducts must have a finish that makes it difficult for them to become dirty. Additionally, they must be accessible at the top for maintenance and cleaning.

• If there is a suspicion that condensation temperature may be reached on the walls of the ducts, they will be thermally insulated to prevent condensation from forming.

• In the case of ducts passing through fire sector separating elements, these must comply with the fire resistance conditions established in section 3 of the SI1 section of CTE DB SI, Fire Safety.

• The ducts must be airtight for their design pressure.

• When the duct for additional specific kitchen ventilation is collective, each extractor must connect to it via a branch that leads into the extraction duct immediately below the next branch.