How can mechanical ventilation systems improve
Indoor Air Quality in schools?

Martin Browne

Test Methods
Case Study/ Field Observation
BIM and IES VE Modellling  

For copy of full dissertation, contact:
martinbrowne1105@gmail.com

Supervisors:
Jim Roche
Conor Mc Gowan

Department of Education Guidelines require CO2 Levels to be below the 800ppm average. This study found CO2 levels were between 850-900ppm in the case studies explored. It was also found that typical temperatures were less than optimal. 

Currently in Ireland there are 3,300 primary schools with 544,696 students, 2,955 job sharing teachers and 42,012 full time teachers. Primary Schools are responsible for 589,663 Individuals. These numbers were issued by the Department of Education as of September 2021.  In Ireland as of January 2022 there was a Covid-19 outbreak in every 1 of 4 primary schools (1000+ Schools). With many classrooms throughout the country currently using a natural ventilation system there is a thermal affect with this, as the CO2 levels rise in the classroom the windows are opened to provide fresh air whilst also removing the heat which was within the room. This sacrifices the internal temperature to provide good indoor air quality. The purpose of this thesis is to examine the existing conditions  of the classroom and to research and analyse how mechanical ventilation systems may be used within these conditions to provide an optimal indoor environment. This will be carried out through modelling the school in Revit and using the IES VE software to examine it. Through analysis of the classroom throughout the school day, 98% of the day was below the optimal temperature of 17°C with approximately 85% of the day below 15°C.

Throughout this thesis there was a data logger placed in two classrooms in Carnaross National School, Co. Meath. The Data logger recorded the Relative Humidity, Carbon Dioxide, and Internal Temperature.  The second test recorded the Relative Humidity, Carbon Dioxide, and Internal Temperature every 5 minutes. The CO2 levels throughout the school day surpassed the recommended CO2 levels of 800PPM for approximately 60-68% of the school day in both rooms, whilst the temperature averaged between 13.5-15°C between both rooms. Furthermore, in a third test completed by the author where all windows were closed for a period of 2 hours, the highest CO2 level recorded was 1482ppm. 

Although the CO2 rose significantly the temperature never rose to above 17°C. The author carried out a study in 25 different schools of which 21 were built prior to 2000 and 19 of those experienced temperature and CO2 problems to a certain degree. BIM and IES VE Modelling was used to gain a greater understanding of airflow within the space. These software’s were used to simulate the indoor environment to provide the author with a greater understanding of the current airflow.