UNE 171380:2024: Continuous indoor CO2 measurement for health prevention and wellness improvement

March 2024

The concentration of carbon dioxide (CO2) in indoor air is a key measure of ventilation efficiency, which depends on occupancy, type of ventilation and room volume. The importance of ventilation lies in its direct impact on health, diluting pollutants and preventing respiratory diseases. However, the use of natural ventilation presents challenges, such as the uncontrolled entry of external pollutants, the difficulty to control its efficiency and the impact on energy efficiency and thermal comfort.

The current regulation, Reglamento de Instalaciones Térmicas en Edificios (RITE), establishes requirements in relation to indoor air quality andCO2 concentration in indoor spaces. And a few weeks ago, the UNE 17138:2024 standard was approved, which seeks to address aspects not covered in relation to the continuous measurement ofCO2 for the protection of health and improvement of well-being.

 ContinuousCO2 measurement: Novel?

Although measuringCO2 is not new, its regulation in current regulations is limited. It is an increasingly common practice and its continuous monitoring is essential to identify the air renewal pattern of a space and, therefore, to effectively and efficiently regulate the ventilation system in place.

What does this standard allow?

The proposed rule seeks to:

  • Generate informed decisions for users.
  • Public access to risk management linked to indoor air quality andCO2 concentration.
  • Add value to companies, organizations or institutions that implement continuousCO2 monitoring.
  • Promote environmental quality as a commercial distinctive.

Scope and objectives of the standard

The standard applies to new and existing buildings for collective use. It complements existing regulations on indoor air quality andCO2 sampling. It aims to maintain a low risk level indoors, especially in relation to the transmission of respiratory diseases.

The standard has general requirements forCO2 meters, which must:

  • Continuous measurement.
  • To be reliable, using NDIR sensors.
  • Transmit measurements to a database.
  • Be fixed and non-manipulable.
  • Include a visualCO2 level alarm system.

Our MICA devices are equipped with NDIR sensors and meet all the necessary resolution and accuracy requirements:


Categorization according to type of space and season

The data obtained from the measurement are categorized according to the type of space and the season of respiratory infections. This allows for the adjustment of acceptableCO2 thresholds according to the potential risk of airborne disease transmission. The standard establishes a traffic light per category (Good, Acceptable, Action Limit) and assigns ratings according to the percentage of time theCO2 concentration is in each color of the traffic light. This provides a detailed assessment of indoor air quality.


The proposed standard is applicable to buildings for collective use, establishing a continuousCO2 measurement systemwith reference values. It is complementary to current legislation and highlights specific requirements for sensors. In addition, it establishes a periodic audit and accreditation process to ensure continuous and reliable operation of the implemented solutions.

This comprehensive approach seeks not only to improve ventilation efficiency but also to protect the health of occupants and provide tools for a more informed management of indoor air quality.

InBiot supports this proposal, which represents a step forward in creating safer and healthier indoor environments. OurCO2 and air quality monitoring devices meet the requirements of the UNE 171380:2024 standard, guaranteeing an optimal indoor environment and complying with the highest quality standards.Contact us to find out how we can help you implement these solutions in your company!

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