Building ventilation and COVID-19 transmission risk
Contents |
[edit] Introduction
Recycle, refit, refurb, reuse and upcycle – often these are words seen around trendy topics like interiors, furniture and sustainability. Indeed, this has been a growing theme globally – reducing waste, making good of what we have got and applying some reimagination and ingenuity.
[edit] Safety indoors
Social distancing and mask wearing can only go so far in preventing transmission of COVID-19 indoors. They are not barriers to contaminated aerosols, which can build up in poorly ventilated buildings. Specialist building service engineers, Milieu, have brought together the latest research on COVID-19 transmission and share their expertise on how to use ventilation to reduce the risk of COVID transmission indoors.
It is generally agreed by the scientific and medical community that the main route of coronavirus transmission is by respiratory droplets (larger droplets and particles that are exhaled when people cough, sneeze, sing, talk or breathe), which are passed on through close contact with an infected individual. Transmission by these larger respiratory droplets is usually within six feet, hence the two metre social distancing rule.
It was discovered that COVID-19 can also be spread through exposure to virus-containing respiratory droplets that remain suspended in the air over longer distances. These smaller droplets are known as aerosols.
Outdoors, fresh air will dilute and disperse any virally charged particles; it is indoors where this mode of transmission puts us all at higher risk of contracting COVID-19. Therefore, unless clever ventilation systems are incorporated into buildings, transmission risk is even higher.
[edit] Healthier airflow
Aerosols tend to follow airflow. Opening windows and doors allows fresh air to enter indoor spaces, increases airflow and reduces the concentration of virally charged particles.
In rooms where this is not possible, alternate methods of ventilation such as air conditioning (AC) need to be used. However, AC systems that recycle air, without an adequate supply of fresh air, could be responsible for recirculating and spreading airborne viral particles.
In traditional AC systems, where units are placed on the wall, airflow is horizontal, potentially delivering infectious respiratory droplets into the pathways of others.
In an underfloor ventilation system installed by Milieu at Pennybank, Clerkenwell, the airflow is vertical, streaming the air up past occupants to be expelled through cleverly concealed vents. This not only reduces the concentration of any virally charged particles, but it also reduces mixing of air between people sharing a working space.
[edit] Ventilation effectiveness
Milieu has developed a Ventilation Effectiveness Toolkit (milieuconsult.com/ventilation-effectiveness-toolkit/) that assesses ventilation using computational modelling. This method analyses volume, occupancy, vocal activity and existing ventilation rates (natural and mechanical) of a building.
In response to experiences associated with COVID-19, we can take steps to reduce its transmission and reduce the infection rate of any future strains of SARs or other viruses, such as flu and the common cold, all of which impact our health and productivity. An effective way of doing this is by improving the ventilation of our buildings.
This article originally appeared under the headline, 'Reduce the risk of COVID transmission: ventilate your buildings' in the Architectural Technology Journal (at) issue 137 published by CIAT in spring 2021. It was written by Milieu Engineering Consultancy.
--CIAT
[edit] Related articles on Designing Buildings
- Back to the workplace: are you prepared?
- CIAT articles.
- Coronavirus and the construction industry.
- Designing HVAC to resist harmful microorganisms.
- Growing focus on IAQ challenges for specifiers and HVAC manufacturers.
- High efficiency particulate arrestance HEPA.
- IAQ developments accelerated by COVID-19.
- Minimum efficiency reporting value MERV.
- Standalone: The new way forward in non-domestic ventilation.
- Ventilation and control of COVID-19 transmission.
Featured articles and news
Heat pump announcements, what homeowners need to know
An 'ultimate guide to heat pumps' from a heating company.
Construction contract awards reach £7.1bn in February
Their highest level in seven months.
The journey to sustainability in heritage
Research is the key to better understanding.
Heritage approaches to adaptation, mitigation and loss.
Bridging the gap between policy, finance and installation.
Development on brownfield land
Definition, background, policy and the latest consultation.
With the Design Framework for Building Services.
Retrofit of Buildings, a CIOB Technical Publication
Pertinent technical issues, measures and the roles involved.
ECA joins HSE campaign to support mental health
Working Minds’ five simple steps based on risk assessment.
Mental health in the construction industry
Mental health issues in brief with related articles.
Transitional arrangements, Building Control and the BSR.
For pre-October buildings with substantial progress by April.
How to write an inspection and test plan
ITPs for quality control and assurance particular elements.
Why quality counts in domestic ventilation systems
From products, to systems to the installation.
Empowering the Future with CIOB Academy
Lifelong learning, upscaling, and reskilling for the built environment.
Winners of the 2024 ASBP Awards
Project, Product and Initiative according to the 6 pillars.