Taking on the COVID Challenge

Taking on the COVID Challenge

The last 16 months have proved extremely challenging with the COVID-19 pandemic. Maintaining good indoor air quality (IAQ) and reducing COVID spread are essential indoors where transmission rates are far higher than outdoors. A raft of research confirms COVID is airborne and the positive effect of ventilation in tackling transmission.

David Cook, technical product manager at Vent-Axia, explains more on using ventilation to fight COVID, and how specifiers can help create safer environments in offices, schools, pubs, gyms, dental surgeries and other buildings with the right ventilation.

It is now widely recognised that ventilation is vital to help reduce COVID-19 transmission. Public Health England guidance acknowledges airborne transmission can occur in ‘poorly ventilated’ spaces and the Government’s public information campaign highlights how ventilating indoor spaces can reduce the risk of coronavirus infection by over 70%. In addition, in the Government’s recently updated ‘Working safely during coronavirus’ document, it outlines eight priority actions for businesses to take to protect staff and customers, including ‘Provide adequate ventilation’.

Taking on the COVID Challenge

A recent article published in the British Medical Journal, ‘Covid-19 has redefined airborne transmission’, emphasises the importance of reducing spread by focussing on tackling close airborne transmission of the virus. This has been followed by an article in the journal Science, which calls for improvements in building design and ventilation to stop the spread of infection and a revolution in how governments regulate indoor air quality. Furthermore, Whitehall was said to have recently been discussing plans to make ventilation mandatory in offices. Add this all together and it shows just how important effective ventilation is in allowing the World to open back up.

Effective ventilation

There are over 2 million non-domestic buildings in the UK. Some use windows for ventilation, others are designed with whole building mechanical ventilation systems, while some are fitted with air conditioning systems that only recirculate the internal air without actually supplying any fresh air. With so many variables, it is essential to have ventilation guidance that ensures systems are up to the job.

The Chartered Institution of Building Service Engineers’ CIBSE COVID-19 Ventilation Guidance’ gives detailed guidelines to minimise the risks of airborne transmission of COVID-19. Within the guidance CIBSE’s overarching advice is to increase the air supply and exhaust ventilation, supplying as much outside air as is reasonably possible to dilute and remove the virus as much as possible. More detailed advice includes: extending the operation times of supply and extract mechanical ventilation systems; starting ventilation at nominal speed at least two hours before the building usage time and switching to lower speed two hours after the building usage time; in demand-controlled ventilation systems lowering the CO2 setpoint to 400ppm to maintain operation; and to keep ventilation on 24/7 with lower ventilation rates, when people are absent.

COVID-19 Ventilation Guidance

Ventilation helps reduce transmission risk and also indoor pollution by bringing in fresh air and exhausting stale, potentially virus-laden, air. The higher the airflow, the more effective the ventilation will be in reducing transmission. While many people are opening windows to achieve this, using extractor fans removes the virus more quickly. This is highlighted in the Government’s public information film ‘Hands. Face. Space. Fresh Air’. However, with a wide range of ventilation solutions available, what should specifiers choose that both improve IAQ and help reduce viral transmission?


With businesses such as pubs, gyms and restaurants currently dependent on being COVID-secure to be able to operate, effective ventilation is at the heart of achieving this. For example, gyms face a higher risk of virus transmission as the moist, warm air combined with turbulent air flow from exercising may create an environment in which airborne virus droplets can readily spread. Government guidance advises gyms reduce occupancy to optimise ventilation.

For the hospitality industry when smoking was allowed in pubs, building guidance was to replace the air in a room every 7.5 minutes to extract the smoke and create a healthier indoor environment, protecting staff and customers. The same solution can be used to help maintain a COVID-secure establishment. Installed and correctly commissioned in pubs, fans will extract the polluted air, including any viruses, replacing it with fresh air every 7.5 minutes, thereby diluting the impact of the virus and reducing transmission. Due to the risk of COVID-19 transmission airflow should be prioritised over thermal comfort inside properties.

Meanwhile for dental surgeries, currently there needs to be a gap, called ‘fallow time’ between patient treatments to minimise the risk of virus transmission. Effective ventilation reduces the fallow time between appointments, reduces the infection rates and keep patients safe by increasing fresh air circulation in dentist surgeries. Current healthcare guidance for new buildings and major refurbishments specifies that a dental treatment room should have at least 10 air changes per hour (ACH). At this rate, the Government guidance advises a fallow time of 15 minutes.

So, what steps should consultants take to ensure buildings have sufficient ventilation? The first step is to evaluate current ventilation systems and where possible increase airflow from existing systems to meet the necessary air changes an hour. The number of air changes will vary depending on the application. It is also important to switch ventilation to full fresh air mode where possible rather than recirculating air and adding fresh air where there is only air conditioning. Systems should always supply as much outside air as possible.

Where a ventilation system has been assessed and isn’t able to provide enough airflow, there are great options for replacing an existing system. Specifiers should not only consider sufficient air changes per hour but also look at ease of installation and replacement – making the installation process easier but also helping reassure business owners that upgrading ventilation isn’t a big job. Modern extract/supply fans are ideal for supplying extra airflow and can easily be retrofitted to reliably supply effective ventilation whilst being energy efficient, helping reduce running costs. For example, Vent-Axia’s Lo-Carbon T-Series Fan range can be easily wall or window mounted yet offers high performance ventilation with low running costs.

Alternatively, if a customer is investing in a whole ventilation system upgrade, Demand Energy Recovery Ventilation (D-ERV) systems have sophisticated controls and sensors that can be used to easily adapt a system to the new COVID-19 requirements, providing ventilation appropriate to occupant needs. For instance, Vent-Axia’s Sentinel Totus² D-ERV has a range of sensors, such as CO2, PIR occupancy detection, to determine the room’s usage and air quality, adjusting the ventilation requirements automatically and managing the system’s ventilation rates accordingly.

With airborne transmission confirmed and the Government repeatedly suggesting ventilation as a way to reduce transmission indoors, it’s clear that effective ventilation is essential in the fight against COVID-19. Specifiers can make a real difference for businesses and other non-domestic buildings by suggesting the right kind of ventilation for each job that will provide enough airflow to dilute the virus in the air and improve IAQ.

Taking on the COVID Challenge

To help specifiers select the best ventilation options Vent-Axia has produced a useful guide called ‘The Effect of Ventilation on COVID-19’ which brings together guidance and information on using ventilation to reduce virus transmission.

Vent-Axia also created a companion webpage at https://www.vent-axia.com/dilutethevirus. In addition, they have created dedicated web pages for those working on projects for dentists and in pubs and bars.

If you are installing or servicing ventilation, Vent-Axia can help you understand the key principles to be COVID-Aware. Email info@vent-axia.com or call the team on 0344 856 0590 for help and advice. For further information on all products and services visit www.vent-axia.com.

Evaluating ventilation systems