Indoor Air Quality Surveys Needed Before Reopening Buildings

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17 March 2021

Bureau Veritas is stressing the need to carry out indoor air quality surveys, swab-sampling programs and quantification of fresh air assessments, to ensure premises mitigate any COVID-19 risks.

Following the latest guidance from the Health and Safety Executive (HSE) highlighting the risks of coronavirus transmission in air conditioning and ventilation systems, organisations are being warned to prepare for this possibility when reoccupying buildings.

While the most common form of COVID-19 transmission is through large particles or droplets, which are let off into the air via sneezing, coughing and breathing and eventually settle on a surface, there is evidence to suggest that the virus can be spread by smaller particles called aerosols, which can remain airborne for several hours. It is these particles that pose the risk when indoor air is recirculated through an air handling unit (AHU).

The HSE guidance comes as many businesses prepare to re-open following two months of national lockdown and urges them to check that they have adequate air conditioning and ventilation systems in place, to ensure all areas of their premises are adequately ventilated to limit transmission of COVID-19 aerosol particles.

“While we’re all aware of the danger of coronavirus transmission via droplets and are regimented in social distancing and hand sanitising to prevent the spread, it can’t be forgotten that the virus can also spread via airborne particles, and thus the onus is on businesses to ensure all procedures are met to mitigate these risks for employees, visitors and customers."

–Joe Marais

Engineering Team Leader – Occupational Hygiene, Bureau Veritas

 

Hospitality and Non-Essential Retail Venues Prepare to Reopen

Those in the hospitality industry, non-essential retail and a number of other commercial buildings having closed to the public throughout the national lockdown and as they once again are faced with the well-versed processes of re-opening, Bureau Veritas asserts that clean air and circulation in indoor venues should be a key part of their strategy as we exit national lockdown.

Joe Marais, Engineering Team Leader – Occupational Hygiene at Bureau Veritas, commented: “There are two ways a business can adequately ventilate their premises. First is natural ventilation, such as opening doors and windows. However, a number of buildings also use mechanical ventilation, these are AHUs and air conditioning units that control temperature, humidity, air movement and cleanliness within a space.

“The vast majority of AHUs are capable of introducing fresh outside air, mixed with a proportion of recycled air back into occupied areas. The key issue that we have found is that the fresh air ratio setting on AHUs has been drastically turned down due to the need to recycle air for thermal comfort. The latest guidance from HSE is discouraging the use of 100 per cent recirculation system settings and is encouraging the supply of fresh outdoor air too.”

Indoor Air Quality Risk Assessments

Marais continued: “While we’re all aware of the danger of coronavirus transmission via droplets and are regimented in social distancing and hand sanitising to prevent the spread, it can’t be forgotten that the virus can also spread via airborne particles, and thus the onus is on businesses to ensure all procedures are met to mitigate these risks for employees, visitors and customers.

“This can best be done by carrying out indoor air quality surveys to ensure that each area of the premises is well-ventilated, looking at where natural ventilation can be incorporated, as well as swab testing samples to assess whether the air that is being recirculated is free from harmful pathogens, especially the COVID-19 virus.”

Picture: a photograph of the interior of an office, showing four people working at a desk

Article written by Ella Tansley | Published 17 March 2021

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