Ventilation in schools

November 2020

This week we celebrate World Children's Day. Tuesday 17 was Student's Day and Friday 20 November is Universal Children's Day. And this year 2020 we celebrate it with uncertainty, with a critical eye, with concern. We are living through a global pandemic where, it is true, children are not the group most directly affected. However, indirectly, they are: they have been out of school for three months, playgrounds have been closed, the way they relate to each other has changed and new rules prevail in their schools.

Suspense in health?

Teachers and school management continue to work to ensure that this situation undermines day-to-day school life as little as possible. And this second wave is corroborating this: schools are becoming those safe environments, where despite the rules, the distance and the mask, the passing of the day brings normality and routine.

But when it comes to Indoor Air Quality, do schools pass in terms of healthiness? The vast majority do not have centralised ventilation systems. We have realised that ventilation is key to ensuring an adequate indoor environment. However, thermal comfort (and the energy bill of schools that have the heating on with the windows open) has taken a back seat.

The importance of indoor air quality for health in our built environment has been discussed many times before - and not just because of the presence of a virus that has disrupted our plans for 2020. Adequate air quality has a direct impact on the ability to concentrate, the speed of task solving, attention and concentration in the educational space.

The challenge is clear: to ensure adequate ventilation, commensurate with actual air renewal needs to reduce aerosols and ensure a healthy indoor environment. It will therefore be particularly useful to monitor the concentration of CO₂ and particulate matter.

What ventilation should an educational establishment have? A normative example

The reference legislation is the RITE (Reglamento de Instalaciones Térmicas en los Edificios), which establishes a series of minimum requirements for indoor air quality in the non-residential sector.

Four categories of air quality or IDA (InDoor Air) are established, from IDA-1 (optimum quality) to IDA-4(low quality).

For educational classrooms, category IDA-2 applies, which corresponds to good air quality. In the case of kindergartens the requirement is stricter, falling into the IDA-1 category.

The ventilation flow rate in these cases can be calculated on the basis of the estimated occupancy or CO₂ concentration:

* 1 dm3=1 litre

In the latter case, the concentration to be added to the CO₂ concentration outside (usually 400 ppm).

What is the current situation of classrooms in Spain?

According to a study by the Passivhaus Building Platform (PEP), classrooms in Spain are out of the comfort zone for 84% of teaching time. The reasons are varied, but are generally related to the lack of an air-conditioning system and, in most cases, the absence of a specific ventilation system beyond the opening of windows. This is mainly due to the age of the buildings, most of which were built before the previous RITE in 1998.

How to make a PRE-diagnosis? An example and an estimation tool:

In this context, and given the seriousness of COVID-19, as well as the need to maintain a ventilated environment, initiatives have emerged to establish appropriate ventilation criteria such as the recently published GUIDE TO VENTILATION IN CLASSROOMS.

At inBiot we wanted to do our bit. We have developed a simple calculation tool that simulates the concentration of CO₂ in the air of a classroom.

Depending on the size of the classroom and the levels of air renewal (ventilation system, infiltrations and window openings), we calculate the ventilation flow rate which, in relation to the number and age of the students, shows us how the CO₂ concentration would evolve over the course of a day. This will allow us to identify whether we are ventilating effectively (and efficiently).

Ventilation in schools

This tool will be available for free use and download in our next post, where we will explain it in more depth.

From theory to practice: MIDAMOS

Learning how to calculate the minimum and necessary air renewal in a school can be key for maintenance staff to adjust ventilation flow rates and system regulation to the actual needs. To this end, more and more voices are confirming the need for diagnosis through continuous measurement of CO₂ concentration as an objective and valid indicator of the adequacy of the ventilation system.

The latest studies indicate that ventilation of classrooms using protocols based on window opening times is not a sufficient option to minimise the risk of coronavirus infection in schools.

The data analysed so far confirms "the lack of assurance of natural ventilation without an objective reference on air quality in the rooms". The experts conclude that the action of ventilating is not meaningful if it is not complemented by measuring CO₂ concentration.

In this sense, inBiot has designed a specific device to help in this situation: MICA Lite.

Provides temperature, relative humidity, CO₂ and PM2.5 data. It has a continuously lit LED light in traffic light mode depending on CO₂, which makes it easy and quick to know when it is necessary to ventilate and when it is not.

In addition, it has an innovative "Virus Indicator" that not only takes into account ventilation to determine the probability of spreading in an enclosed space, but also other air quality parameters that directly influence the survivability of viruses in the space.

All data can be tracked and consulted in real time on our cloud platform My inBiot, from anywhere and on any device. A demo of MICA Lite's real-time monitoring is available via this link.

Good indoor air quality is an important component of a healthy environment that ensures the best learning conditions . Let's make a commitment to safe schools.

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