Ventilation Grilles and Other Components for Your Project

The Technical Building Code in its Basic Document HS. "Health" indicates the obligation to employ a hybrid or mechanical ventilation system in projects for housing, waste storage, vehicle parking, and garages. This implies the use of ventilation grilles and other key components in ventilation systems. When we are carrying out a housing project in any of its typologies: detached housing, block housing, townhouses or semi-detached houses, we must be clear about which of the two systems is the most appropriate. To do this, it is useful to distinguish their differences:

• The hybrid ventilation is one in which the extraction process of air by mechanical means only comes into operation when external pressure and temperature conditions prevent its operation by natural ventilation. In a natural ventilation process, fans are not used; instead, a circulation flow of air is created inside by natural means, taking advantage of the differences in pressure and temperature that exist between the air inside the house and the outside. For this purpose, ventilation grilles (identified as admission openings by the CTE DB HS3, and commercially as air vents) are usually placed in properly sized exterior carpentry to ensure that this flow is constant and has minimal impact on the energy consumption of the dwelling. These grilles can be manually adjusted to control the flow of air extracted and transported outside through vertical ducts that reach the roof. One of the main constraints of a hybrid ventilation system is that extraction and supply ducts should not be horizontal, as this would greatly hinder the operation of the installation during natural ventilation processes. That is why hybrid ventilation is appropriate in single-family housing projects, or attached or semi-detached houses, where the floor area occupied by the habitable spaces is not very large, and therefore there is no impediment for all the ventilation pathways to be vertical until they reach the roof level.

• In a mechanical ventilation system, admission ventilation grilles (identified as admission openings by the CTE DB HS3, and commercially as air vents) mechanically regulated, are located on the facade. The extraction of polluted air is done through an extractor connected by ducts to the humid areas of the house (kitchen and bathrooms). In mechanical ventilation, there is no limitation on using a single vertical duct that serves all floors of the building. In this way, the expulsion of the air flow from each home may be done through horizontal sections hung under a false ceiling until it reaches this main duct. When we are designing an installation that needs to service many homes simultaneously, as happens in block housing projects, a mechanical ventilation system should be employed.

• Extraction openings and admission openings: are responsible for supplying renewed air or extracting stale air from different rooms. They are located at the ends of the ventilation ducts where the grilles can be opened and closed manually or mechanically. Ventilation grilles are usually metallic, made of galvanized steel or aluminum, although they can also be made of PVC, zinc, titanium, wood, or reconstructed stone.

• Ventilation ducts: whether circular or rectangular in section, they must be designed to produce minimal pressure loss, accumulate the least amount of dirt possible, and minimize noise that could disturb users. To do this, the number of bends cannot be excessive and must be made at a 45° angle throughout the layout. To ensure the proper functioning of the installation, ducts cannot have abrupt variations in diameter.

• Fans: function to circulate air towards the ducts, creating depressions or overpressures in the surrounding air.

• Heat exchangers. By incorporating these devices into the ventilation system, thermal energy is recovered from the extraction of polluted air in winter. In summer, they are responsible for cooling the outside air that is brought inside the spaces. All of this contributes to increasing the energy efficiency of the installation.

• Extractors. Extractors are small electric devices used to ventilate certain rooms inside a home. They help maintain the walls, ceilings, and joints in good condition by evacuating air to the outside and preventing condensation.