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Ventilation and Air Conditioning During The COVID-19 Pandemic


It’s the law that workplaces have an adequate supply of fresh air and this hasn’t changed during the COVID-19 pandemic. In fact, it’s been established that good ventilation is one of the key measures that can help reduce the risk of the coronavirus spreading.


But why is this?


Good ventilation helps to reduce the concentration of the virus in the air and this means people are less likely to breathe it in if they’ve been in an enclosed area with someone who has the virus.


Identification of action areas


There are several simple steps that can be taken when trying to identify areas where ventilation isn’t up to scratch.


  • Look for places where there isn’t mechanical or natural ventilation.

  • If an air conditioning or ventilation system doesn’t have an outdoor air supply or is recirculating air, it’s likely the area is going to be poorly ventilated.

  • If there are any areas that feel stuffy or have an unpleasant smell, it’s a good sign that there isn’t adequate natural ventilation.

  • Detectors can be used to monitor CO2 levels, giving an indication of poor ventilation levels. They will work best in areas where the same group of people congregate and are less effective in sparsely populated areas.


The more people who occupy a particular area with poor ventilation, the greater the risk that coronavirus will be transmitted. Activities like singing, shouting and aerobic actions tend to generate higher levels of aerosol (particles of moisture potentially carrying the virus) and this will increase the risk further still. When assessing whether the level of ventilation is adequate, note should be taken of the kinds of actions that occur in the workspace.


Steps to take to improve ventilation


Although open windows and vents can provide a good source of natural ventilation, it should be remembered that fire doors must not be propped open.


If an area is fully occupied, doors and windows should not be completely closed, as this can lead to the ventilation level dropping and a risk to the health of those present.


As temperatures drop and winds increase, this will likely increase the degree of natural ventilation through openings. Doors and windows won’t have to be opened so wide to achieve the same level of ventilation, and this can increase the temperature of the workplace, leading to a more comfortable working environment. If windows need to be opened wider, those at higher levels will cause the fewest draughts.


Airing rooms as often as possible will lead to better ventilation. Opening all the doors and windows wide will increase the quality of air in the room generally, although it is usually best to do this when there is nobody using the space.


If the heating is inadequate to bring the temperature up to a satisfactory level, employers could consider allowing employees to wear extra layers or warmer clothing. Another solution to overcome low working temperatures is the use of fan convector heaters, but it should be remembered that their use is recommended only in well-ventilated areas.


HVAC and mechanical ventilation


Mechanical ventilation, also known as HVAC (heating and ventilation air conditioning) is a system for bringing in fresh air to a building and heating it at the same time, if needed. However, it needs to be used in a particular way to ensure it gives the most benefit at the lowest risk during the pandemic.


Most mechanical ventilation can still be used as normal, but it should be set to maximise fresh air and recirculate as little air as possible. If it can be set to operate both before and after work areas are used, it should be.


If a recirculation system is being used that doesn’t draw in a supply of fresh air, it can still be used, provided windows and doors can be left open to bring outdoor air into the workspace.


If a mechanical system is supplying individual rooms, this may permit higher amounts of fresh air to be provided, and this should be continued.


As always, employers should not neglect the servicing timetable and ensure that it is done by a reputable and reliable person in line with the manufacturer’s instructions.


Work vehicles


It’s often forgotten that when it comes to health and safety, vehicles are also counted as workplaces. Therefore, ventilation in vehicles needs to be addressed as much as that in buildings.


When people are in the vehicle, the ventilation system should be switched to fresh air input, rather than recirculated air. Thought should also be given to keeping windows open to improve ventilation, although if it is cold, that can be done partially.


If the vehicle is to be used by different people each time, the air inside should be allowed to clear between uses; that could be by opening all doors and windows and allowing fresh air to circulate.






Written by

Ken Cook, Health and Safety Advisor at rradar