The regulation that governs indoor air quality, Indoor air quality has experienced growing social interest as a result of the pandemic that began in early 2020, especially in multifamily buildings where a large number of people accumulate on a permanent basis and the transit is, consequently, exceptionally intense and constant.

The regulations that govern indoor air quality: CTE and RITE

The Strategic Plan for Health and Environment 2022-2026, approved in November 2021, has among its main objectives “protect the health of the population against the adverse effects of poor air quality”. Among other aspects, the high cost to our healthcare system, the vulnerability of the child population and the relationship with respiratory diseases.

The same document explains that “poor indoor environments (IAQ) cause numerous diseases: respiratory, infectious, allergic, asthma, and even cancer. There are numerous factors chemical (air quality, tobacco, building materials and furniture, radon, etc.) as physical (noise, lighting, thermal comfort, humidity) and biological (microbes, viruses, and allergens) that influence the health of building occupants.”

The Spanish regulation concerning air quality is governed by the Technical Code for Buildings (CTE) in section HS3 of 2019, which is mandatory in “housing buildings, inside them, waste storage areas, storage rooms, parking lots, and garages”. Its objective is the eradication of the contaminating elements that are habitually present in multifamily buildings. To achieve this, it establishes several methodologies based on CO2 concentration and minimum ventilation flows.

For premises of any other use not mentioned in CTE HS3, the current regulation is the Regulation of Thermal Installations in Buildings (RITE), whose last modification dates from March 2021.

Application of CTE HS3

The regulation that governs indoor air quality establishes the following points in the preamble:

1. Buildings will have means for their rooms to be adequately ventilated, eliminating contaminants that are habitually produced during the normal use of the buildings, so that a sufficient flow of outdoor air is provided, and the extraction and expulsion of the contaminated air is guaranteed.

2. To limit the risk of indoor air contamination of buildings and the outdoor environment in facades and patios, the evacuation of combustion products from thermal installations will generally occur through the building's roof, regardless of the type of fuel and the device used, in accordance with specific regulations regarding thermal installations.

Additionally, the regulation establishes that “the flow of outdoor air supplied must be sufficient to eliminate contaminants not directly related to human presence. This condition is considered satisfied with the establishment of a minimum flow of 1.5 l/s per habitable room during periods of non-occupation.”

Likewise, in the cooking area of kitchens, “there must be a system that allows the extraction of contaminants produced during their use, independently of the general ventilation of habitable rooms. This condition is considered satisfied if there is a system in the cooking area that allows an extraction flow of at least 50 l/s.” Lastly, it should be noted that the regulation states that houses must have a general ventilation system that can be both hybrid or mechanical among other technical aspects.
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