The role of ventilation in stopping the spread of COVID-19
‘Ventilation isn’t just for COVID, it’s for all working life, and we’ve got to invest in ventilation in all our workplaces’.
In a recent article for LocalGov, Hywel Davies – Technical Director of the Chartered Institution of Building Services Engineers (CIBSE) – suggests that although the situation is under review, there is an expectation that businesses premises could reopen as early as Easter, when a large proportion of the working age population may not have been vaccinated.
That means the focus in workplaces and multi-occupant spaces, especially those open to the public, must remain on limiting transmission to prevent the spread of coronavirus to un-vaccinated people.
The article highlights advice from the Government’s Scientific Advisory Group for Emergencies (SAGE) in its document Role of Ventilation in Controlling SARS-CoV-2 Transmission, which is that: ‘Ventilation should be integral to the COVID-19 risk mitigation strategy for all multi-occupant public buildings and workplaces.’
Hywel argues that the need for effective ventilation in helping limit the spread of COVID-19 is based on growing evidence that coronavirus can be spread by tiny particles called aerosols.
The acts of breathing, talking, coughing and sneezing all produce droplets and aerosols that may, if the host is infected, contain pathogens. Larger droplets fall by gravity within 2m from the source, which is why social distancing is recommended. The droplets land on surfaces and can therefore get onto hands – hence the importance of regular hand washing and avoiding touching the face. Smaller aerosols, however, can stay airborne for hours, which enables them to travel longer distances where they could infect secondary hosts, particularly in poorly ventilated spaces.
Hilda Palmer, from Manchester Hazards Centre, a campaigner and facilitator of Families Against Corporate Killers and SHP’s Most Influential Individual in Health & Safety for 2020, told SHP: “Ventilation in most of our workplaces has been poor for many years and workers have been complaining about the levels of dust and microbes, volatile organic compounds, bacteria, viruses and now we’ve got COVID. They are all building up in the air and if you don’t move that air by good ventilation, then people are going to get sick with COVID and sick from a lot of other things.
“So, we’ve got this theatre of hygiene, we’ve got workers exposed massively to dangerous combinations of cleaning chemicals and disinfectants and cleaning things manically. Whereas, what we really need to do is clean the air, ventilate. We’ve got to make ventilation a bigger issue. Ventilation isn’t just for COVID, it’s got to be for all working life, and we’re going to have to invest in ventilation in all our workplaces, including in schools.
“Our argument is we want people to go back to work, but they can’t go back to work until it’s safe. There is no case of going back to schools on 8 March, if nothing has been done to make them safer, since last autumn when cases rocketed very much due to the transmission in schools.”
Keep a look out on SHP in the coming weeks, for the full interview with Hilda.
How ventilation of indoor spaces can help to stop the spread of coronavirus
Public Health England has published advice and information on how ventilation of indoor spaces can help to stop the spread of COVID-19, including how to increase ventilation at home and in other settings.
It explains that ventilation is the process of introducing fresh air into indoor spaces while removing stale air. Letting fresh air into indoor spaces can help remove air that contains virus particles and prevent the spread of coronavirus.
When someone with COVID-19 breathes, speaks, coughs or sneezes, they release particles (droplets and aerosols) containing the virus that causes COVID-19. While larger droplets fall quickly to the ground, smaller droplets and aerosols containing the virus can remain suspended in the air. If someone breathes in virus particles that are suspended in the air, they can become infected with COVID-19. This is known as airborne transmission.
In poorly ventilated rooms the amount of virus in the air can build up, increasing the risk of spreading COVID-19, especially if there are lots of infected people in the room. The virus can also remain in the air after an infected person has left.
Bringing fresh air into a room and removing older stale air that contains virus particles reduces the chance of spreading COVID-19. The more fresh air that is brought inside, the quicker any airborne virus will be removed from the room.
Ventilation is most important if someone in a household has COVID-19 or if you are indoors with people you do not live with. Good ventilation has also been linked to health benefits such as better sleep and fewer sick days off from work or school.
Ventilation does not prevent COVID-19 from spreading through close contact and is only one of the actions you should take to reduce the spread of COVID-19.
Workplace and non-domestic settings
In terms of workplaces, the document notes that ventilation should be considered as part of making your workplace or indoor public space COVID-secure.
It is important to identify and deal with areas that are not well ventilated. The more people occupying an area that is poorly ventilated, and the longer they remain in it, the greater the risk of spread of COVID-19.
Control measures such as avoiding certain activities or gatherings, restricting or reducing the duration of activities, providing ventilation breaks during or between room usage should be considered alongside ventilation for reducing the risk of airborne transmission.
Any actions to improve ventilation should not compromise other aspects of safety and security (for example, avoid propping open fire doors), and should consider other consequences such as health and wellbeing impacts from thermal discomfort.
Employers should provide employees with clear guidance on ventilation, why it is important, and instruction on how to achieve and maintain good natural ventilation or to operate systems if there are user controls.
Mechanical ventilation systems are maintained in line with manufacturers’ instructions. Set ventilation systems to using a fresh air supply and not recirculating indoor air, where possible.
The full guidance, which also advises on ventilation in vehicles, is available here.
Read the HSE’s, Ventilation and air conditioning during the coronavirus pandemic guidance, here.
Sleep and Fatigue: Director’s Briefing
Fatigue is common amongst the population, but particularly among those working abnormal hours, and can arise from excessive working time or poorly designed shift patterns. It is also related to workload, in that workers are more easily fatigued if their work is machine-paced, complex or monotonous.
This free director’s briefing contains:
- Key points;
- Recommendations for employers;
- Case law;
- Legal duties.