Is your building adequately ventilated?

In light of the COVID-19 pandemic, the Federation of European Heating, Ventilation and Air Conditioning Associations (REHVA) have released guidance documents on the safe use of ventilation systems during the current pandemic. There is a general guidance document and guidance document for schools.

One of the recommendations to help optimise ventilation is to install a CO2 monitor with traffic light indication, especially in rooms in where ventilation depends on opening windows as this visualises the need for additional ventilation. This applies to all spaces that are occupied by multiple persons for more than one hour, such as public area, offices and classrooms.

The reasoning behind this, is that for many buildings sufficient ventilation is a challenge. Although mechanical ventilation systems can ensure a continuous air exchange throughout the year, checks should be made as to whether the ventilation systems are functioning correctly and the way in which the systems controlled potentially modified to change set points or bring in more fresh air. However any checks are only valid at the point they are carried out.

Many buildings are naturally ventilated (e.g. opening windows). Natural ventilation significantly depends on the temperature difference between the indoor and the ambient air and the current wind situation. As a result, sufficient natural ventilation cannot be guaranteed at all times. When natural ventilation systems are manually controlled, the winter months present a significant issue, as without a visual prompt, the occupants may be reluctant to open windows due to the outside temperature.

There is also the guidance from the UK Government, which states that in the absence of known ventilation rates in public areas such as leisure centres and gyms, Carbon Dioxide monitors are required to be used as a surrogate indicator to switch on additional mechanical ventilation or open windows.

There is approximately 400ppm of Carbon Dioxide in the atmosphere, yet we breathe out around 40,000ppm each time we exhale. It is for this reason that CO2 Monitoring is used as a general indicator of whether a room is properly ventilated. If there are high levels of CO2, the probability is that other contaminants are still present.

Although CO2 traffic light indicators are typically set to change to amber at 1,000ppm and red at 1,500ppm, during the pandemic, it is advised by REHVA to temporarily change the default settings of the traffic light indicator to 800ppm and 1,000ppm respectively in order to promote as much ventilation as possible.

The Flamefast CO2 Monitor is already widely used in Schools and Offices for this application and provides a bold, simple to follow Green, Amber, Red indication to prompt further ventilation. The updated monitor has a number of user selectable programs that allow the traffic light set points to be easily changed between the standard and temporary recommended setting, so the monitor will continue to be a useful indicator once the pandemic is over. There is also a mains rated volt free contact if you wish to interlock the monitor to a ventilation system to provide a boost facility.

With a typical life span in excess of 10 years, once installed the self-calibrating sensor is maintenance free and provides full compliance with all government and industry guidance.

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