Workplace ventilation and COVID

The HSE has recently reminded employers about the importance of ventilation in the workplace. It is an appropriate time to remind ourselves of some of the basic rules.

In practical terms, you should consider the following issues:

  • People should work from home if they can
  • You should review and update your COVID-19 Risk Assessment.
    • This assessment should be updated regularly to reflect the changing situation in your workplace.
  • You should require all workers on your sites to follow the social distancing rules.
  • People should keep at least 2 metres apart at all times.
  • Social distancing rules should be included in the site induction training for all workers (and contractors).
    • This should also be reinforced through toolbox talks.
  • You should require any contractors to cover social distancing in their RAMS and ask them to tell you how they will manage and enforce it.
    • You can share the responsibility with contractors.

COVID-19 has been with us for nearly two years and businesses are still learning how to cope with it. One simple message is: “Keep your workplace ventilated to reduce the risk of spreading COVID-19”.  Good workplace ventilation helps reduce the risk from the person-to-person aerosol transmission and so reduces the spread of COVID-19. With the arrival of colder weather, more people are reluctant to keep doors and windows open to ventilate the workplace.

Workplace ventilation

The advice from the HSE is to try and balance ventilation of the premises with keeping people warm at work. Take simple steps to make sure your workplace is adequately ventilated without workers being too cold.  Such steps include:

  • partially opening windows and doors as this can still provide adequate ventilation
  • opening higher-level windows to create fewer draughts
  • if the area is cold, relaxing dress codes so people can wear extra layers and warmer clothing

How do you know if your workplace is adequately ventilated?

Using carbon dioxide (CO2) monitors to identify poorly ventilated areas of the workplace. Your risk assessment should identify areas of your workplace that are usually occupied and poorly ventilated. CO2 monitors can help you do this, as people breathe out CO2, which can then build up in the workplace. A build-up of CO2 in an area can indicate that ventilation needs improving. The most appropriate portable devices to use in the workplace are non-dispersive infrared (NDIR) CO2 monitors, which measure CO2 levels in parts per million (ppm).

How much is too much CO2?

A consistent CO2 value below 800ppm is likely to indicate that an indoor space is well ventilated. On the other hand, CO2 levels consistently higher than 1500ppm in an occupied room indicate poor ventilation and the need to take action (improve ventilation and/or reduce the number of workers in the area).

Improving ventilation

Simple and cheap ways to improve natural ventilation include fully or partly opening windows, air vents, and doors. Note: Do not prop fire doors open, the fire services have displayed warning about doing this.

Airing rooms regularly helps to improve ventilation. Opening all the doors and windows as fully as possible maximises ventilation in a room. You can do this when people leave for a break and even 10 minutes an hour can help reduce the risk from the virus in the air, depending on the size of the room.

If you have mechanical ventilation, ensure that it is working properly and is serviced regularly. Ensure that you understand how it works and use it appropriately to improve workplace ventilation. On some mechanical systems, the amount of fresh air taken in can be controlled. Beware of systems that only recirculate air without drawing in fresh air. Monitor such systems carefully (CO2 monitor) and open windows as required.

Other simple steps

  • Review the dress code, and allow workers to wear layers to tolerate cooler, more ventilated conditions
  • Set the heating to maintain a comfortable temperature even when windows and doors are open and review other sources of heating
  • Reduce the number of people in the workspace (such as by home or hybrid working, if appropriate).