C.T.E. HS 3. The development of ventilation regulations in our country

The air quality that we breathe significantly impacts our quality of life, being the cause of many respiratory diseases that affect our health and comfort. Sometimes, it is within our homes where air pollution is higher, reaching up to 5 times worse than outside. This aspect profoundly influences public health in any country, as we currently spend over 90% of our time in indoor spaces whether in offices, shopping centers, or within our homes. Fortunately, improving indoor air quality is a problem with a solution that is easier and more economically viable than addressing the difficult situation of atmospheric pollution faced by many major cities around the world.

The World Health Organization (WHO) itself describes the Sick Building Syndrome as the symptoms of discomfort and health issues that affect regular users of so-called smart buildings, which are characterized by a high degree of airtightness, high technology, and a widespread use of synthetic building materials. As a consequence, a set of standards, regulations, and certifications have emerged in Western countries that incorporate indicators of sustainability, health, and wellbeing for regular users of any type of building.

C.T.E. HS 3. Spanish regulations regarding indoor air quality

Since 2008, modifications have been introduced within the Technical Building Code (C.T.E.) and the RITE indicating very specific requirements regarding air quality. Specifically, the C.T.E. in its Basic Document HS 3, "Indoor Air Quality", specifies the minimum flows of ventilation that must renew the rooms of a dwelling, as summarized below:

• Bedrooms: 5 l/s per occupant
• Living rooms and dining rooms: 3 l/s per occupant
• Bathrooms and restrooms: 15 l/s in each room
• Kitchens: 2 l/s per m² of usable area
• Parking and garages: 120 l/s per parking space
• Storage rooms and common areas: 0.7 l/s per m² of usable area
• Waste storage: 10 l/s per m² of usable area

Biohabitability

This is a new approach to construction and architecture considering knowledge and evidence from the fields of health and human biology. The goal is to provide constructive solutions that are compatible with biological systems, creating healthier spaces. To achieve this, the design of a building is valued, analyzing the interaction between materials, construction systems, installations, and execution, considering the use of materials that minimize the incorporation of volatile organic compounds, formaldehyde, certain plasticizers, and heavy metals. It is also sought that building materials have an adequate behavior with electrostatic loads and with the electroclimate, so that they are not a source of ionizing radiation.

A clear example of how environmental factors can be considered when designing the construction of a building is semicircular lipoatrophy. This is an idiopathic condition characterized by atrophy of subcutaneous fat tissue in the form of a semicircular depression. Low relative humidity associated with a more technical environment and materials that are poor at dissipating electric fields are common in spaces that have been frequented by people affected by this type of syndrome.