The study also makes recommendations to public authorities. Like the deployment of the Tertiary Eco Energy System, which provides a direction for energy trajectories to 2030; clarifying the thresholds for good "IAQ" around three targeted pollutants and monitoring them over time will promote both air efficiency and energy efficiency in tertiary buildings.
IAQ is becoming a crucial public health issue but is still poorly understood by stakeholders in the tertiary building sector (project owner, design office, builder and operator). At the same time, the tertiary sector is racing to reduce its energy consumption by 40% by 2030.
For 24 months, 12 public (schools) and private (offices and shopping malls) project owners have committed one or more of their buildings to accelerate this learning, based on experimentation and measurement. Thanks to the contribution of this community, the study carried out by Cerema and IFPEB makes methodological, organizational and technical recommendations for decision-makers and site managers.
First of all, characterizing the simple, measurable and universally understandable objectives of good IAQ is like setting a 19-degree objective for energy efficiency.
For example, setting a temperature target of "19°C" makes users want to raise awareness (put on a sweater, etc.), to talk, to adjust the installations, to take action, etc. In the same way, setting IAQ targets makes it possible to initiate action: monitoring pollutants, raising user awareness of IAQ, reducing pollutants at source, etc.
Indoor air quality in a building results from a balance between the different sources of pollution: the building itself with the materials or furniture, the users and the necessary renewal of this stale air. In order to initiate a path of progress, it is essential to characterize the objectives of good IAQ around three simple and measurable pollutants over time: carbon dioxide (CO2), total volatile organic compounds (tVOCs) and fine particles (PM2,5).
For buildings affected by the obligation to install control systems (BACS decree), an obligation could be added for continuous monitoring of IAQ with micro-sensors on a sample of premises (1 per 1.000m² for example). The installation of these sensors, with direct reading, with feedback of data on supervision is possible at a lower cost for the building (<1€/m².year).
Like construction products (floors, paints, etc.) which already have a labelling system for indoor air emissions, this could be extended to cleaning products, furniture (chairs and desks for example) and school supplies (paints and glues).
“Sobriety: the best kWh m3/h is the one we don’t need”
Secondly, it is essential to evacuate residual pollutants. Mechanical ventilation has a significant effect on improving IAQ (CO2 and PM2,5); equipped sites have better IAQ than sites without ventilation, but is not a "green light" on tVOCs. To evacuate tVOC peaks, it is recommended to combine active occupant management with opening windows. Finally, mechanical ventilation must absolutely be well maintained over time to maintain its effectiveness.
For sites without mechanical ventilation, it is possible to evacuate pollutants by ventilating better, i.e. more frequently and for a shorter period of time. This makes it possible to involve occupants in controlling the quality of the air in their interior, and achieve up to 50% measured reduction in the average concentration of VOCt in some of the buildings.
In both cases, this strategy on air efficiency requires a dialogue between departments to raise awareness among occupants. A direct reading of the levels of pollutants reached must be made available to them in order to see the impact of their changes in behavior.
“Aeraulic Efficiency: the right m3/h is the one renewed at the best time.”
Public authorities will be able to use these recommendations to accelerate the QAI/Energy reconciliation in the tertiary sector.
More information can be found on the publication at this link.
This program is funded by Ademe and the Ministry of Ecological Transition (General Directorate for Risk Prevention) for schools.
Illustrative image of the article via Depositphotos.com.