Health: requirements of the Technical Building Code

Do you know what the requirements of the Technical Building Code regarding health are? In this article, we will explain the relationship between chapters 1 (Protection against moisture) and 2 (Indoor air quality) with ventilation systems.

The basic document establishes that buildings must be designed, constructed, maintained, and used in a way that meets hygiene, health, and environmental protection requirements (which are encompassed under the concept of health). Meeting these requirements will, on one hand, minimize the risk of occupants of a building (as long as it is used under normal conditions) suffering from ailments or illnesses, and, on the other, reduce the deterioration of the building itself and its surrounding environment.

HEALTH: PROTECTION AGAINST MOISTURE

According to the CTE DB HS 1, Protection against moisture, it is mandatory to limit the dangers that may arise from the improper presence of water or moisture in buildings. Therefore, methods must be in place to prevent the penetration of water from the outside, which may come from rain, runoff, the ground, or condensation.

To avoid annoying moisture inside your building, and consequently the ailments or diseases that may arise from it (respiratory problems, general discomfort, bad odors, colds, sinusitis, etc.), it is essential to have a good ventilation system, ensuring the extraction of stale air (contaminated by CO2 emitted by people as a result of their respiration) and the supply of clean, fresh air free from bacterial contamination.

Natural ventilation: an ineffective system

Traditionally, the necessary process of ventilating spaces has been carried out through natural ventilation, whether it is unilateral, cross-unilateral (the air current originates by opposing the inflow and outflow of air) or by thermal lift (through vertical ducts).

This natural ventilation system has proven ineffective. Although the last two benefit from the pressure difference between the overpressure at the entrance and the depression at the outlet, they do not ensure that the rooms are protected against moisture, which means there is no guarantee against the presence of fungi and mold (the constant opening of windows and balconies conflicts with the necessary thermal comfort and the desired energy savings). Additionally, it must be considered that natural ventilation by thermal lift does not work if there is thermal inversion or if external conditions do not favor the necessary Venturi effect to generate air currents.

HEALTH: INDOOR AIR QUALITY

According to the CTE DB HS 3, Indoor air quality, the necessary air renewal must be carried out thanks to the installation of intake openings in dry rooms (living rooms, dining rooms, and bedrooms) and extraction openings in wet areas (kitchens, sanitary rooms, and laundry rooms).

This hybrid ventilation system, while more effective than natural ventilation, also has disadvantages. From an energy perspective, it is ineffective: since the system lacks airtightness, it is not possible to control air flows. Furthermore, as it lacks heat recovery devices, it is not possible to increase the temperature of the air entering from outside. From a comfort standpoint, it is also not advisable: because it is an unbalanced system, control over the inflow and outflow rates cannot be established, and humidity conditions cannot be controlled.

Controlled mechanical double flow ventilation: an effective and efficient solution

To avoid all these inconveniences and ensure that the air entering the interior of the building is healthy, free of impurities and contaminants, it is recommended to install a controlled mechanical double flow ventilation system, where the supply and extraction are carried out by mechanical means. This system allows for the installation of a heat recovery unit (so that the air blown in from the outside enters pre-tempered). Furthermore, as it is a balanced system, it is possible to act on the air flow volume and on the relative humidity (by means of sensors).