CTE HR Why is the Technical Code so demanding in matters of noise protection?

Our lifestyles have changed significantly in recent decades. So much so that the World Health Organization (WHO) states that in cities, people spend between 80% and 90% of the day in enclosed spaces: offices, schools, shops, homes, etc. For this reason, it warns us that well-being and comfort of people depend greatly on the quality of the indoor environment of these spaces, that is, the quality of air and acoustic insulation that allows the building to insulate us from noise coming from outside. This is why, in recent years, regulations aimed at preventing health problems caused by excessive noise have been incorporated into the sector. Such is the case of the Technical Code of Construction (C.T.E. HR) which in its Basic document HR- "Protection against noise", emphasizes the level of acoustic insulation that the construction elements of a building should have, mainly the exterior facade enclosure, the roof, and the partition walls.

Regarding air quality, it should be noted that this problem affects not only exterior spaces, but also the interior of our homes, where contamination can be up to five times higher than that of the outside. This is mainly due to the materials used in construction: paints, varnishes, plastics, or carpets that emit contaminating substances. The trend to build increasingly airtight homes to reduce energy consumption only exacerbates the poor quality of indoor air, especially when the user does not ventilate the home regularly.

C.T.E. HR. Protection Against Noise

The Technical Code in this basic document establishes the levels of acoustic insulation that the rooms of a building must have depending on their use. This level of insulation is not only established concerning external noise that enters through the facade enclosure but also regarding the noise that may arise between different rooms within the building, thereby avoiding the discomfort or illnesses that noise can cause to users.

The C.T.E. HR clearly differentiates between two types of spaces: protected spaces and habitable spaces. The protected spaces are those that, due to their characteristics, must have better acoustic conditions than others. In the case of residential buildings, they are:

• Bedrooms
• Dining rooms
• Libraries
• Living rooms

In educational buildings:

• Classrooms
• Conference rooms
• Libraries
• Offices

In healthcare or hospital buildings:

• Operating rooms
• Patient rooms
• Waiting rooms

In administrative buildings:

• Offices
• Meeting rooms

The habitable space is defined as an interior space that requires appropriate acoustic, thermal, and sanitary conditions. These include kitchens, bathrooms, toilets, hallways, distributors, and stairs in any of the previously defined uses.

The values of acoustic insulation against airborne noise defined in the Technical Code range from 30 dBA for bedrooms and rooms in residential and hospital use, to 47 dBA for bedrooms and rooms of any use. These variations are due to the increase of the Day Noise Index (Ld) that the Technical Code uses to define the acoustic insulation of the different types of premises. The Ld is a weighted index that defines the long-term average sound level, that is, the average of all sound levels produced daily over a year in a given location.

The correct sizing of the ventilation installation is particularly relevant when it comes to preventing excessive noise inside a home. Ducts with a cross-section that is too small in relation to the air flow that will circulate through them will cause excessive noise inside the rooms. The same happens when the supply or exhaust openings do not have the appropriate dimensions.