Covid 19 Spread and Ventilation


If you can maximise the amount of fresh air in your building, then you help to minimise the risk of Covid-19 spread. Ventilation will reduce your risk of aerosol virus transmission but will not have an impact on either droplet transmission (so keep social distancing) or transmission via contaminated surfaces (so keep up regular disinfection activities).

It is estimated that an infected person exhales around 100,000 Covid particles per minute so virus concentrations can rapidly build up in an enclosed space. Workers sharing the same air are therefore at risk. The Chartered Institution of Building Services Engineers recommends a minimum of 10 litres per hour of fresh air per person.

6 Key Actions for Good Ventilation

1. Start by opening windows for at least 15 minutes prior to the building becoming occupied or between shift changes.

2. Try and keep occupancy levels at a reasonable level and remember that if you half the occupancy, you are effectively doubling the ventilation rate. 

3. Where members of the public use the building, control entry times and numbers.

4. Where workers are undertaking strenuous work or are shouting, their breathing rates will increase and will not only exhale more virus particles but also need more fresh air. Assess any areas where such activities take place and place additional limits on numbers, increase ventilation or limit the time spent working there.

5. Identify areas that have poor ventilation such as those that have a bad or stale smell or use a ‘smoke test tube’ to see whether there is any air movement in a particular location.

6. Be prepared to take additional measures during the autumn and winter to avoid complaints of draughts and cooler working conditions. Relax dress codes to allow the use of warmer clothing, move workstations away from open windows and use higher-level windows for ventilation to avoid creating draughts. Warm air fan heaters should only be used in areas that are well ventilated.

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