School classroom CO2 monitors: where to use them
As the government-provided carbon dioxide (CO2) classroom monitors arrive in schools, headteachers are faced with the decision of how to best deploy them.
School CO2 monitors: deciding where to use them
As the government-provided carbon dioxide (CO2) classroom monitors arrive in schools, headteachers are faced with the decision of how to best deploy them. With temperatures plummeting, it is tempting to close windows providing the all-important ventilation to reduce the of Covid virus transmission. But how much ventilation is needed to keep the space safe? That’s where the classroom CO2 monitors come in, more on this later. But, in the absence of having one CO2 monitor for every room in school, it will be important to prioritise their placement to those rooms with the least ventilation in proportion to its level of use. This article suggests a way to achieve this, at least for schools that don’t have the luxury of pre-installed devices in all rooms.
How can I work out where to position my school CO2 monitors?
The table below this article presents a way to help you decide where to deploy classroom CO2 monitors as equipping every room in school with a monitor is likely to be prohibitively expensive. CO2 monitors measure relative carbon dioxide concentration in the air that we all breathe out, so while this is not in itself a measure of Covid, it will highlight areas where ventilation is poor so the potential for the virus to spread is greater.
If not already done, it would be helpful to conduct an assessment of all rooms occupied by groups of people for an extended period of time (remember to include your staff room, meeting rooms and other multi-occupancy offices) to identify the spaces that will be harder to moderate the air quality due to their size (in relation to the number of people using them) and/or the ability to provide adequate ventilation, either natural or mechanical. CO2 monitors will not be as effective in areas where occupancy varies over a short period of time such as hallways or toilets, so you can disregard those.
Prioritise your school CO2 monitors to the least ventilated, most densely occupied rooms in school
This assessment could be carried out by a member of staff applying the definitions provided in the table below to classify your rooms into three ‘RAG’ categories. This is not a direct science and common sense will be required when applying the definitions (giving consideration to size of windows vs. size of room and occupancy etc) but this will help focus attention on the most needy areas of school, which is the aim.
What do the CO2 monitor readings mean for classrooms?
Your distribution of air quality monitors can then be allocated to those spaces in greatest need of monitoring, maximising efficiencies while also mitigating the greater risks. Of course the monitor will only be useful if it is monitored! Ideally internal spaces should have a ‘parts per million; (ppm) reading of below 800ppm but this is especially important in rooms used for continuous talking, singing, dancing or exercising.
Further information is available from HSE
See the table below to help decide where to deploy your CO2 monitors…