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Controlled vs uncontrolled air flow in the age of Covid-19

Throughout the Covid-19 pandemic, ventilation has become a primary tool in the fight against the virus’s spread.

Living in a country with a cooler climate, the population spends more time indoors – particularly in winter.

This situation has facilitated the spread of Covid, with cases peaking at just over 68,000 in early January 2021.

It is accepted that good ventilation reduces the risk of transmission in areas where people are gathered together.

Mercifully, the mass roll-out of the Oxford AstraZeneca vaccine and others has led to a massive drop in cases and fatalities.

But over the last 12 months, the importance of good ventilation in fighting viruses has come to the fore, often mentioned in the same breath as masks, hand washing, and social distancing.

How does good ventilation prevent Covid-19?

Adequate ventilation reduces the amount of Covid-19 virus suspended in the air, thereby decreasing the chance of it entering into a person’s respiratory system.

Conversely, indoor areas with poor ventilation see an increase in the risk of disease transmission.

However, ventilation reduces the aerosol risk but has much less of an impact on:

  • droplet transmission (where people are within 2m of each other)
  • contact transmission (touching infected surfaces)

Controlled vs uncontrolled air flow

‘Ventilation’ is the process of controlling air flow in a building. Effective ventilation methods include simple measures like being able to open windows and doors, and mechanical ventilation systems which bring fresh air in via fans. There are numerous types of mechanical ventilation system. A common system is ‘exhaust-only ventilation’ which exhausts stale air and pulls in fresh air via inlets, cracks and other air-leakage sites.

‘Air leakage’ is an example of “uncontrolled air flow” in a building; when outside air enters and conditioned air leaves. While air leakage is a form of ventilation, too much leakage could result in excessive cold air entering in winter, making it more difficult (and expensive) to heat a property.

The Covid-19 pandemic has underlined the importance of being able to ventilate a property when necessary, while also being able to manage “uncontrolled” air flow – i.e. air permeability levels.

Get in touch with Air Tightness Testing Ltd to learn about our air permeability/air leakage testing services, available to developers across England.

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We are registered with iATS (Independent AirTightness Testing Scheme) and use equipment calibrated by UKAS laboratories. Our testing procedures are also recognised by UKAS.