RITE and ventilation, requirements to comply with the regulations

In recent decades, the regulations in construction have taken a leading role in the real estate and residential sector. The Technical Building Code has been updated to current times and to the needs of a sector where energy efficiency and health are now paramount. And for over two decades, there has also been the RITE, which stands for Regulations on Thermal Installations in Buildings, which was approved by Royal Decree in 2007.

What does the RITE contribute to the construction sector? Primarily, it is the standard that establishes the needs for energy efficiency and safety that all buildings must meet when making thermal installations.

First of all, it must be understood what the RITE considers as thermal installations. Typically, they are as follows:

• Heating systems and heating in homes and workplaces.
• Air conditioning units and other cooling mechanisms.
• Mechanical or hybrid ventilation for air renewal.

The application of the RITE has never had retroactive effects, so it must only be taken into account in newly constructed buildings and those that are to be renovated or undergo maintenance processes, although thermal installations for processes in industry or agriculture are excluded.

Basically, all new construction or renovation processes must apply the standards and requirements specified in the RITE.

The more technical and specific nature of the RITE compared to the Technical Building Code means that it is available in Technical Instructions, known as IT. These instructions present requirements for maintaining the thermal quality of the environment or, for example, ensuring the acoustic environment. Special emphasis is placed on limiting noise levels and vibrations in thermal installations, a problem closely associated with traditional air conditioning systems. Likewise, it is very important in the Technical Instructions of the RITE to ensure indoor air quality.

Regarding the quality of air to breathe indoors, the RITE specifies that it is essential to have a ventilation system that provides the necessary airflow from the outside. At the same time, it must be capable of extracting air that has lost quality due to activities indoors, such as cooking, working, cleaning, or simply using the rooms.

Something very important when considering the RITE requirements concerning indoor air quality is that, if we are analyzing residential buildings, the applicable regulations should be those included in the Basic Document HS3 of the Technical Building Code. In this case, the RITE will apply to all other types of constructions and projects, such as workplaces and work environments.

How does RITE consider indoor air quality?

The RITE, being a much more technical regulation, does not refer globally to air quality loss or a poor state of what we breathe. Instead of focusing on the extraction of air as is commonly emphasized in the CTE, the RITE focuses on the supply of air to public spaces or places where large numbers of people gather.

The regulations on thermal installations seek for buildings and indoor spaces to have certain levels of air quality, depending on the type of construction and their functionalities:

• IDA 1, optimal quality air. It is the highest quality and must be required in hospitals, medical centers, laboratories, and child care centers such as nurseries.
• IDA 2, good quality air. This is required in offices, common areas in hotels and apartments, public spaces, schools, and other areas.
• IDA 3, medium quality air. Required in commercial buildings, cinemas, theaters, hotel rooms, hospitality centers, gyms, and other leisure spaces.
• IDA 4, low quality air. Not suitable for any space.

Based on the specifications in each section covered in the RITE, the next important step will be to calculate the ventilation flow for each of these scenarios.

The best method covered in the RITE for calculating the flow - or at least the most common - is the indirect method of outdoor air flow per person. In this calculation, it is not necessary to take measurements of carbon dioxide levels or the particles required in other methods. Although it is not the most effective, it is always necessary to conduct a type of calculation based on the type of project, in a personalized manner.