The recent news that more than half of the UK now has Covid-19 antibodies is an encouraging step towards a return to normal life. Having said that, ‘normal’ will mean something different for all of us from now on.
The heightened level of safety consciousness we’ve all been left with in Covid’s wake isn’t going to disappear overnight. Indeed, observing best practices to improve air quality in indoor spaces should help to protect people against all sorts of airborne contaminates – Covid, and otherwise.
With that in mind, in this post we’re looking at how indoor ventilation systems can help fight viruses.
How viruses go airborne
Airborne viruses like Coronavirus essentially piggyback on aerosols; miniscule droplets which can be breathed in as people go about their business. That’s why wearing a face covering has become so commonplace. Masks block the majority of aerosols from entering the airway and thus reduce the risk of infection.
Outdoors, the concentration of viral particles is understandably low. They dissipate into the air where they pose a low risk of someone breathing them in. Indoors, however, is a different matter. The higher the concentration of viral-packed aerosol, the greater the risk of viral transmission.
That’s where good ventilation comes in.
How good ventilation can help protect you against viruses
The key goal of ventilation of indoor spaces is raising the air exchange rate. Essentially, that means replacing the stale indoor air with fresh air from the outside. In homes, that happens mostly from opening windows and doors – which is why we were all encouraged to do so even in the colder winter months.
Commercial buildings however rely on heating, ventilation and air conditioning (HVAC) systems, which remove the old stale air and replace it with new, fresher air – aiming for between three and six air exchanges per hour in order to be sufficient to help keep viruses at bay.
However, keeping a good circulation of fresh air indoors is only part of how ventilation can help prevent the spread of viruses. The other is filtration.
How HEPA can help
HEPA filters are pleated mechanical filters made from fibreglass, foam or cotton and remove up to 99.97% of airborne particles – including ones carrying viruses. They’re used in many commercial and industrial settings to remove harmful particulates, and are a major component of our own extraction systems.
However, some confusion remains about their effectiveness in this area. To address is, it’s worth looking at the details.
Particle sizes play a big part
Our HEPA filters are certified to capture particles up to 0.18 microns and
higher. A Coronavirus particle is roughly around 0.1 micron, and thus technically just about able to make it through a HEPA filter when it’s flying solo.
However, as mentioned above, airborne viruses like Coronavirus do not actually float naked through the air. They make a home in airborne droplets which are often at least 10 microns or larger. Just in terms of size alone, then HEPA filters are realistically able capture the vast majority of potentially harmful Covid-carrying aerosols.
The way particles move also matters massively
Size isn’t the only factor that determines how well a filter can capture particles which might technically be small enough to make it through, as this video shows:
In simple terms, large particles have a lot of inertia. Like a car traveling at high speed on a winding road, this results in them crashing into the many criss-crossing fibres of a HEPA filter and being captured. This is called inertial impaction.
The very smallest particles on the other hand have very little inertia and tend to ‘dance around’ in the air like a mayfly, weaving a convoluted path that also sees them getting captured. This is called Brownian Motion.
Additionally, a filter fibre will also capture a particle if that particle comes within a one particle radius of it. This is known as Interception.
Protecting your staff and customers
As a result, ventilation and extraction systems fitted with HEPA filters are proving an effective way to protect workers from the spread of airborne viruses.
And that’s how good ventilation can help protect you against viruses – by maintaining a good air exchange rate, and filtering out the particles that can carry viruses like Covid-19.
This, together with best practices around mask wearing, and sensible application of at-source extraction solutions, is the best way to keep your workers and customers safe as the world returns to normal following the global pandemic.
Need filters or extraction solutions? We can help
We can also create custom solutions depending on your industry and needs.
Not sure what you need? Get in touch – we’ll be happy to help.