Dr. Parag Rastogi is Lead Building Physicist at Arbnco (Glasgow, Scotland), where he leads research and development efforts to incorporate cutting-edge research into the health, wellbeing, and climate products.
This is an extended version of the article which appeared in May/June edition of BS News here. You can also view a recording of the associated webinar, recorded in Part 1 of ASHRAE Ireland Chapter COVID-19 mini-series at the end of this page.
The COVID-19 pandemic has had a major short-term impact on workplaces, as people work from home or are unable to work. However, the virus will continue to impact workplaces even as lockdowns ease, since new measures to protect workers’ health must be implemented. The health-promoting aspects of buildings have always been important to our long- and short-term health, wellbeing, comfort, and productivity. The pandemic has sharpened minds to the immediate and catastrophic impacts of building design and operation on disease transmission.
It is virtually certain that social interaction and accessing public places poses a risk of transmission of virus between infected persons and others. Prevailing government guidance on prevention and public health reflects this (NHS 2020; CDC 2020). The upshot is that buildings need to operate assuming aerosol transmission is a sufficiently serious risk. Our recommended approach involves four key features and is based on the Hierarchy of Controls approach (CDC and NIOSH 2015): (1) implement engineering and administrative controls, (2) measure and verify outcomes, (3) inform and engage occupants, and (4) review and improve.
Implement Engineering and Administrative Controls
The controls recommended by professional societies are summarised in Tables 1 and 2 (ASHRAE 2020; CIBSE 2020; REHVA 2020). While several strategies can reduce the risk of transmission, no interventions or combinations of interventions will reduce the risk down to zero. Existing recommendations for controlling the risk of infections in workplaces should be considered by building managers and operators as part of reopening buildings after the ongoing disruption.
Measure and Verify
A protocol is only as good as its implementation, which is why we explicitly include measurement and verification. Most actions recommended for healthy building operation have measurable outcomes, either directly (e.g., temperature) or through proxies (e.g., CO2 for ventilation). Measuring the outcomes of these actions using sensors and inspections/surveys translates engineering intent into operational reality.
Since pathogen transmission considerations have been exacerbated by the current pandemic, we recommend additional measurement points in vulnerable places. These include potential sources such as toilets and elevators. Since the best protection in these places is adequate ventilation/exhaust (ASHRAE 2020; REHVA 2020; CIBSE 2020), a simple CO2 measurement will suffice for general prevention.
Inform and engage occupants
Push notifications and feedback or surveys through the arbn well system can additionally both be used to inform occupants about policies and actions and encourage them to participate in building operation. Occupants often have the best understanding of how policies are working and how hazards are developing or being controlled (OSHA 2020).
Review and Improve
As the properties of COVID-19 are better known, the guidance will change. While it may not feel intuitive, guidance that changes when the evidence demands it is more reliable. Much of the guidance here is based on the understanding of previous epidemics such as SARS, MERS, and H1N1. Some solutions and actions will be modified once more is known about how the virus infectivity and routes change over time.
To improve recommendations for the operation and design of air conditioning and ventilation, we need to be able to determine how long people have spent in a location (dwell time), the directional pathways of airflow around these locations (local, directional airflow), and the level of ventilation necessary to remove airborne transmission of droplets among people in the same space (Pantelic 2019). This process will have to be iterative, and no single action alone will be enough (ASHRAE 2020; REHVA 2020).
While the workface begins to recover from COVID-19, effective planning is vital to ensuring a safe transition back to work for employees. To minimize both potential direct and aerosol transmissions, we propose a strategy comprised of four key features: building operation guidelines, measurement and verification of outcome metrics, occupant notification and engagement, and constant review. Adhering to professionally recommended controls for building operation, both through building engineering and management, allows businesses to better controlling potential infection risks. By then verifying and examining the measurable outcomes of these recommendations, such as temperature, CO2, and occupancy, through arbn well sensors building and facilities managers can better implement and adjust the proposed controls. Coupled with occupant engagement through feedback, surveys, or push notifications employers can continuously remind occupants of policies and have them contribute to strategy adaption and implementation. Reviewing the plan based on the results of measurements and surveys will ultimately help us to ensure that unintended consequences are minimised, and improvements implemented rapidly. By taking all these considerations in mind, we hope to provide building owners and managers the tools to create healthy indoor environments that suppress the transmission of viruses such as COVID-19.
ASHRAE. 2020. ‘ASHRAE Position Document on Infectious Aerosols’. Atlanta, GA, USA. https://www.ashrae.org/file%20library/about/position%20documents/pd_infectiousaerosols_2020.pdf.
CDC. 2020. ‘Coronavirus Disease 2019 (COVID-19) – Prevention & Treatment’. Centers for Disease Control and Prevention. 24 April 2020. https://www.cdc.gov/coronavirus/2019-ncov/prevent-getting-sick/prevention.html.
CDC, and NIOSH. 2015. ‘Hierarchy of Controls’. Workplace Health and Safety Topics. CDC. 13 January 2015. https://www.cdc.gov/niosh/topics/hierarchy/default.html.
CIBSE. 2020. ‘CIBSE COVID-19 Ventilation Guidance’. Version 1. London, UK: The Chartered Institution of Building Services Engineers. https://www.cibse.org/coronavirus-covid-19/emerging-from-lockdown.
NHS. 2020. ‘Staying at Home and Away from Other People (Social Distancing) – Coronavirus (COVID-19)’. Nhs.Uk. 22 April 2020. https://www.nhs.uk/conditions/coronavirus-covid-19/staying-at-home-to-avoid-getting-coronavirus/staying-at-home-and-away-from-other-people/.
OSHA. 2020. ‘Hazard Prevention and Control’. Occupational Safety and Health Administration. 2020. https://www.osha.gov/shpguidelines/hazard-prevention.html.
Pantelic, Jovan. 2019. ‘Designing for Airborne Infection Control’. ASHRAE Journal 61 (7): 64–65.
REHVA. 2020. ‘COVID-19 Guidance’. REHVA: Federation of European Heating, Ventilation and Air Conditioning Associations. 3 April 2020. https://www.rehva.eu/activities/covid-19-guidance?no_cache=1.
Sobek, Olivia Nile, Parag Rastogi, Graeme Jephson, and John Allison. 2020. ‘Best Practice Guide for the Installation for the Installation and Maintenance of an Arbn Well System’. Best Practice Guide 1.3. Glasgow, UK: arbnco Ltd. https://arbnwell.com/wp-content/uploads/2020/05/Best-Practice-Guide-20200512-003.pdf.
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