Covid-19: Should public buildings and workplaces take greater responsibility for improving indoor air quality?

While most people can explain the logic behind ‘Hands, face and space’ and as a result took the recommended action, the role of ‘fresh air’, or ventilation, in stemming the spread of Covid-19 may yet to be fully understood by the public.

 We have written a details document to explain both the reasoning and importance, and suggest solutions for improving indoor air quality in public spaces.

The problem

When someone with a virus breathes, speaks, coughs or sneezes, tiny droplets and particles are scattered into the air. Some larger drops will fall onto surfaces, but smaller particles are suspended and circulate in the air. This is particularly important to appreciate as people may have Covid-19 without showing any symptoms. These droplets and particles may remain in the air for some time, even after the infected person has left the room. As a result, the Government introduced guidelines to reduce the amount of time people spend indoors with those they do not live with, and to encourage the opening of windows.  Ventilation, whether it be natural by opening a window or vent, or a mechanical ventilation heat recovery system or local extractor fan, these can all help reduce the risk of infection. There are simple steps that can be taken to improve ventilation, but in many instances natural ventilation may not be enough. Mechanical ventilation, especially in high density occupation areas like hospitals, schools, shops, and workplaces needs to play a larger part in our fight to stop the spread of Covid-19 and other airborne viruses.  

The importance of ventilation

Until very recently, mechanical ventilation has largely been ignored by the Government, especially compared to natural ventilation, like the opening of windows and doors in schools. Unfortunately, relying on purely natural ventilation has its drawbacks. For example, when opening a window, it can be difficult to control the airflow depending upon the force and direction of the wind and it may not ventilate deep into the space. In an open plan office, for example, it may only provide fresh air to people seated close to the windows and not reach high risk areas such as meeting rooms or communal areas. This is especially the case where classrooms or offices only have windows down one side of a room. Although something is better than nothing, what is really needed now, and in the future, is to be able to guarantee air change rates or fresh air levels. This is where mechanical ventilation can play an important role.   

The problem, however, may go deeper than simply having a form of mechanical ventilation in place. New mechanical ventilation systems should be providing 100% fresh air, but many older systems have a lot of air re-circulation rather than introducing fresh air.  Re-circulation typically takes two forms: –

• a central system feeding lots of rooms with air extracted from a room and then dispersed back to all the rooms fed by the system, or
• where an air-blown heater or extraction unit re-circulates the air within the same room.

Fresh air, via windows, may complement these systems, but for many users it is about achieving a desired and consistent temperature and so windows are often closed to allow the system to operate efficiently. Therefore, there is a heightened chance of transmission of viruses like Covid-19 from older ventilation systems which re-circulate potentially contaminated air. 

Although the Government has provided some guidance on the mechanical ventilation of rooms with, for example, the number of air changes per hour in medical rooms, classification of rooms needs reviewing and hence compliance is currently inconsistent.  

As an example, dental surgeries, which logically would be high risk due to working on the mouth and having a greater chance of transmission via droplets and aerosols, often only have opening windows. Whereas, pre-Covid, they would be treated as clinical rooms for compliance purposes, current advice from Public Health England (PHE) increases standards of mechanical ventilation to those of treatment rooms – thus requiring a minimum of 10 air changes per hour to be fully compliant. This means that it is unlikely compliance would be achieved in rooms where the only ventilation is the use of open windows.

On the other hand, operating theatres require 25 air changes per hour, which would appear more appropriate for the most complex dental procedures. Certain operations require a specific classification called ‘ultra clean’ and these have enhanced filtration with HEPA (High-Efficiency Particulate Absorbing) filters. Although they have re-circulation in the room, the air change per hour rate goes up to 125. We expect to see a lot more operating theatres being upgraded as ‘ultra clean’, and this is already reflected in our enquiries and business. However, some of these clients have been discussing this since last year with hospitals facing difficulties in getting their business cases approved.

Why more must be done

Addressing the need for adequate fresh air ventilation is something we should have been doing long before this pandemic. In addition to existing building regulations a ‘building MOT’ or health check would help provide the structure and guidance needed to ensure that all equipment, including the ventilation, is sized correctly, appropriately operated & maintained and on a regular basis. We regularly test electrics, fire alarms, sprinklers, lifts, water systems and more, so why not the ventilation?

Guidance, education, structure, and support from the Government and help from associated bodies such as the Chartered Institution of Building Services Engineers (CIBSE), and Public Health England is needed on ventilation.  Public spaces like schools and hospitals should be prioritised and urgently need Government funding and direction. 

We should be addressing the problem before the lawyers get involved and start to look for people to blame if an infection is proven to have been caused by poor ventilation in a public space where a solution is available. Collectively we need to go beyond ‘just’ achieving compliance and start planning ahead to go beyond compliance. The Government needs to take the lead, seeking input and knowledge from the experts at the professional institutions.  The CIBSE already provides its own documentation and best practice but even this feels too cautious to make the big changes needed, whilst the Health Technical Memoranda on ventilation (which were in the process of revision) will also require a rethink. This pandemic has really highlighted that significant changes are needed, and quickly, and that nothing should be left off the table.

To encourage the public back, businesses, schools, hospitals, and shops have taken proactive action with regards to ‘Hands, face, space’ with hand sanitiser available, the wearing of face coverings compulsory and floor marking and signage to encourage social distancing. But little action has yet been taken with regards to the ‘fresh air’ aspect and to protect employees, pupils and the wider public. Anyone responsible for a public building or workplace should consider the risks posed in failing to provide adequate fresh air in their indoor spaces and any possible consequences. 

Unfortunately, viruses like Covid-19 are likely to become a more regular problem and as people become more educated on airborne transmission, they may start to avoid buildings with inadequate ventilation.