How the filtration of the incoming air decreases the particle concentration within a school equipped with a balanced ventilation system

Résumé et principaux résultats

Abstract: To study the impact of the filtration efficiency level on the particle concentration in a rural school equipped with a balanced ventilation system with heat recovery, measurements of indoor and outdoor particle concentrations have been carried out by using 3 different efficiency filters: G4, F7 and F9 according to NF EN 779 (2012). Air has been sampled alternatively and continuously inside the fresh air duct at the inlet of the air handling unit (AHU), inside the delivered air duct at the AHU outlet and inside the exhaust air duct. These samples have been analyzed by an optical particle counter for particle concentration measurements in the 0.3 - 10 microm particle size range. Particle concentration values have been used for the filtration efficiency calculation as well as for the calculation of the I/O ratio of the indoors to the outdoors particle concentration. The results show that the efficiency of the G4 filters on the finest particles (< 1 microm) is close to zero. The filtration efficiency is respectively 47 to 55 % with the F7 filters and 82 to 87 % with the F9 filters at 0.4 microm. When the school is unoccupied, the I/O ratio decreases as the filtration efficiency increases. When the school is occupied, the I/O ratio is the same as when the school is unoccupied considering particles smaller than 0.5 microm. For larger particles, the I/O ratio is higher and increases when the particle size considered increases and when the filter class decreases. The I/O ratio exceeds 1 depending on the class of the filter and the particle size considered. In summary, the ventilation system used in the studied school is able to protect people as the I/O ratio is lower than 1 for the most harmful (diameter < 1 microm) and most abundant (99 % in number) particles recorded outdoors when fine filters (F7 or even better F9) are installed within the air handling unit.
Titre : Comment la filtration de l'air neuf diminue la concentration en particules dans une école équipée d'un système de ventilation double flux
Résumé : Article support d'une présentation à la conférence AIVC 2015, Madrid, Espagne, 23-24 septembre 2015.

Commissions

Filtration de l'air, Ventilation des bâtiments résidentiels et tertiaires

Thème

Ventilation et qualité de l'air

Mots-clés

Filtration, Filtres, Qualité de l'air intérieur, Qualité de l'air intérieur et extérieur, Ventilation

Auteurs

GINESTET Alain, PUGNET Dominique, ROBITU Mirela