Air-Conditioning and Covid-19 – Can HVAC Spread Coronavirus?

This article looks how Covid-19 can be transmitted in the workplace and whether building heating, ventilation and air-conditioning systems can make matters worse. It explains how building owners and facilities managers can minimise airborne transmission by following a few simple steps, how changes or HVAC upgrades can help to reduce longer term risk, and why improving airflow patterns can have a significant impact on controlling disease spread. It concludes by looking at ways to minimise the spread of coronavirus between rooms and how this can be achieved.

Can air-conditioning spread Covid-19?

A year on from the start of the Covid-19 pandemic, we know a lot more about the way the virus is transmitted than we did back then.

We know that the main ways the virus spreads is through the air and by touching contaminated surfaces, and in order to mitigate these risks, we’re all socially distancing, cleaning our hands and wearing masks in public places.

The World Health Organisation (WHO) has also identified aerosol transmission of the virus, which can be a particular issue for people who are spending a lot of time in smaller, unventilated rooms with many other people.

Many businesses have already transformed the way in which they operate over the last year by installing new one-way foot-traffic systems, putting up screens or physical barriers, ramping up their cleaning regime, moving desks to create more space and staggering start and finish times to minimise the number of people in a building at any one time.

Businesses are also starting to think about their heating, ventilation and air-conditioning systems (HVAC) to try to address the issue of indoor airflows.

Minimising airborne transmission of Covid-19 from air-conditioning and ventilation systems

Before looking at your HVAC air-conditioning systems in more detail, there are some “quick fix” options which can also help reduce coronavirus risk. Some things to consider are:

Optimise Seating Plan
Position desks to minimise the number of staff sitting in the same airflow path.
Increase Natural Ventilation
If you have a basic ventilation which doesn’t filter the air – open the windows where possible.
Control Your Environment
If you have a central HVAC air-conditioning system, lock the windows to avoid air being pulled in from outside to minimise fan activity due to changes in temperature.
Hand Dryers
Replace hand dryer blowers in bathrooms with disposable paper towels.

What we learned from SARS

Our previous experiences in dealing with Severe Acute Respiratory Syndrome (SARS) in 2004 showed that air-conditioning and ventilation systems have the potential to spread virus from one affected person to others, especially in conditions of high-speed airflow.

HVAC system changes and upgrades

A few tweaks to the settings in your air-conditioning and ventilation systems might help reduce the possibility of Covid-19 spreading in your buildings.

One of the most important changes is in ducted systems, by increasing the rate of exchange of air within the building with fresh air from outside.

This increase in fresh air reduces older air recirculating within the building.

Many businesses turn their HVAC off overnight or at weekends, but you may not be aware that leaving it running at all time can help to minimise airflow.

If your air-conditioning or ventilation system isn’t modern and doesn’t allow for the flexibility of increasing airflow, all is not lost.

Think about changing some aspects of the system hardware, such as upgrading fans which run at a fixed speed with ones where the settings can be adjusted.

Upgrading the controllers and introducing high-performance air purification systems are also an option, but can be costly.

Improving airflow in HVAC systems

Scientists are still working on modelling how coronavirus spreads through air, but there are things you can do to change airflow patterns to minimise risk and these include:

Slow & Steady
Keeping the air flowing slowly and steadily.
Laminar Flow
Preventing a turbulent airflow by encouraging a vertical laminar flow.
Remove Contaminated Air
Funnelling any contaminated air out of the building and away from occupants.

If you can change airflow patterns to get air moving in a straight path and at the same speed, this might help reduce the airborne transmission of virus particles.

This is tried and tested technology, and is currently being used in hospital operating theatres and clean rooms, with systems designed to direct air from ceiling down to floor.

Changing airflow patterns isn’t straightforward though, and is much more complex than simply tweaking the settings on your HVAC controller.

With new-builds, during the design and construction phases, designers and builders must incorporate enough air outlets into the initial design.

If you are refurbishing or upgrading the services in an existing building, then this can involve adding extra outlets in suspended ceilings or replacing outlets covers with covers designed to produce laminar flow.

Correct placement of the outlets is critically important, and the position depends on occupancy, placement of furniture, and the architecture of the room.

Controlling the spread of coronavirus between rooms

It’s also worth thinking about the potential for virus to spread between rooms within a building.

The first step in this type of evaluation is to assess how the air moves through rooms, then looking at whether installing new devices or upgrading the existing HVAC system would help.

There are lots of possible steps to take, from simple changes like closing or installing doors or fitting air curtains, through to more complex changes such as re-configuring airflow performance, sealing suspended ceilings or generating over-pressure.

Specialist indoor air quality solutions for workplaces

WTS offer a comprehensive range of indoor air quality testing and workplace investigation solutions to support business owners, property managers, health and safety professionals, and facilities management specialists.

Our experts can provide advice and support to help you identify the most appropriate strategies for the identification, investigation and prevention of air quality issues.

With offices in London serving the South and South East England, Manchester (North West), Birmingham (Midlands), Bristol (South East England and Wales), Leeds (North and North East) and Glasgow (Scotland), supported by regional teams of specially trained engineers, air quality specialists and technicians we offer cost effective environmental support solutions across the whole of the UK and Ireland.

Contact us today to learn how our workplace management solutions can help improve the safety and performance of your heating, ventilation and air conditioning systems.