building hvac operational best practices
TRANSCRIPT
Building HVAC Operational Best Practices
Advancing Better Indoor Air Quality in the Age of COVID-19
Updated October 14, 2020
For additional information please contact:Bala Gnanam, VP - Energy, Environment & [email protected]
bomatoronto.org
Introducing the HVAC Advisory Council and its panel of experts and industry leaders.
BOMA Toronto would like to acknowledge and thank the members of its Return To Work Committee and the HVAC Advisory Council for their support for and input in the development of this document.
BOMA Toronto HVAC Advisory Council
Co-Chairs:Bronwen Edgar, Risk Manager – Sunnybrook Health Science Centre, Epidemiologist; Infection prevention & control
Dr. Brian Fleck, Professor, Faculty of Mechanical Engineering, University of Alberta; HVAC system expert; Area of current research HVAC - “non-pharmaceutical intervention”
Luke Leung, Director, Skidmore Owings & Merrill; Member of ASHRAE Epidemic Task Force; Vice Chair, Environmental Health Committee – ASHRAE; UK Royal Academy of Engineering COVID-19 Task Force
Dr. Jeffrey Siegel, Professor, Department of Civil and Mineral Engineering, University of Toronto; Ventilations & Air Cleaning ExpertMembers:
Liviu Craiu-Botan, National Manager – Energy & Technical Services + Platform Services Team, Oxford Properties Group
Sarah Clarke, VP – Office East, QuadReal Property Group
Cosimo Commisso, Director – Portfolio Operations, Toronto Office, The Cadillac Fairview Corporation
Peter Halkias, VP – Real Estate Management, Epic Investment Services
Graham Leah, Director – Property Management Services, City of Toronto
Martin Luymes, VP - Government & Stakeholder Relations, Heating Refrigerating and Air Conditioning Institute of Canada (HRAI)
David Matarasso, Principal – Property Management, BentallGreenOak
Randall Rothbart, Partner, Solomon Rothbart Goodman LLP; BOMA Toronto Legal Counsel
Gary Summers, Partner & President, Crown Property Management
BOMA Toronto staff members:Susan Allen, President & CEOBala Gnanam, VP – Energy, Environment & AdvocacyGail Taylor, Sr. Manager – Marketing & Communication
2
BOMA Toronto Return to Work Committee
3Landry Biles The Cadillac Fairview Corporation Limited
Joe Brown KingSett Capital
Anthony Casalanguida RioCan
Catherine Cherwinka Adgar
Barbara Ciesla Allied REIT
Eva Circosta Oxford Properties
Sarah Clarke QuadReal Properties Group
Cosimo Commisso The Cadillac Fairview Corporation Limited
Paul Davis Infrastructure Ontario
Jon Douglas Menkes
Antonyos Fanous Infrastructure Ontario
Silvia Fraser Infrastructure Ontario
Randal Froebelius MaRs
Peter Halkias Epic Investment Services
Kevin Hallford Brookfield Properties
David Hoffman Hines
Donald Hogarth BentallGreenOak
Robert Horst Oxford Properties
Grant Humes Toronto Financial District BIA
Brodie Johnson Hines
Taryn Kelly QuadReal Properties Group
Ellen Kennedy IvanhoeCambridge
Searl Kibel Forgestone
Graham Leah City of Toronto
Luke Leong SOM
Christopher Lieb Oxford Properties
J.P. Mackay Allied REIT
Michael Manuel The Cadillac Fairview Corporation Limited
David Matarasso BentallGreenOak
Neil Mathews Oxford Properties
Patrick Matozzo City of Toronto
Maryanne McDougald First Capital REIT
Sandi Mileta-Clancy Triovest
Bill Minnis Oxford Properties
Marvin Morgan BentallGreenOak
Tera Oswald Infrastructure Ontario
Angelo Potkidis The Cadillac Fairview Corporation Limited
Liann Rea Brookfield Properties
Randall Rothbart Solomon Rothbart Tourgis Slodovnick
Steven Sorensen The Cadillac Fairview Corporation Limited
John Spano Oxford Properties
Gary Summers Crown Property Management
Beverly Tay Oxford Properties
Kelly Veale Triovest
Ian Yorston Brookfield Properties
BOMA Toronto staff members:
Susan Allen, President & CEO
Bala Gnanam, VP – Energy, Environment & Advocacy
Gail Taylor, Sr. Manager – Marketing & Communication
Table of Contents 4
Introduction
General Practices
Non-Mechanical Strategies
Mechanical Strategies
• HVAC
> Ventilation
> Upgrading & Improving Filtration
> Air Cleaning Technologies
> Building Pressure Control
> Maintenance
• Building Automation System (BAS)
• Water & Plumbing System
Special Tools
Glossary of Terms
References & Resources
Disclaimer
5
6
6
7
8
11
12
13
14
16
18
The heating, ventilation and air conditioning (HVAC) systems in buildings are critical
to the comfort, health and safety of their occupants. Lately, there have been concerns
about the potential for COVID-19 to spread through buildings’ HVAC systems.
According to ASHRAE, the transmission of SARS-CoV-2 through the air is sufficiently
likely that airborne exposure to the virus should be controlled1. According to U.S.
Centers for Disease Control and Prevention (CDC), the cases involving transmission of
virus through HVAC occurred within enclosed spaces that had inadequate ventilation2.
There is also sufficient data to support that it is much more common for the virus that
causes COVID-19 to spread through close contact with a person who has COVID-19
than through airborne transmission3,4,5.
Changes to building operations, including the operation of heating, ventilating and
air-conditioning systems, can further reduce airborne exposures. It should be noted
that the World Health Organization recently acknowledged that aerosol transmission
cannot be ruled out for some situations. They emphasized more research is needed to
demonstrate conclusively its role in the spread of the virus6,7.
The content of this document is drawn from multiple sources, including the ASHRAE
Epidemic Task Force – Building Readiness (Sept. 30, 2020)8, the opinions of experts
in the area of air filtration and air cleaning, as well as information that was shared
through BOMA Toronto’s Restarting Smart Series of workshops and webinars.
It should be noted that there is no way to totally eliminate the potential risks. This
collection of best practices for the operation of HVAC systems may help to reduce any
potential risks and advance better indoor air quality.
Introduction 5
1 ASHRAE Position Document on Infectious Aerosols, Apr 14, 2020, https://www.ashrae.org/file%20library/about/posi-tion%20documents/pd_infectiousaerosols_2020.pdf
2 U.S. Centers for Disease Control and Prevention (CDC), https://www.cdc.gov/coronavirus/2019-ncov/prevent-get-ting-sick/how-covid-spreads.html
3 U.S. Centers for Disease Control and Prevention (CDC), https://www.cdc.gov/coronavirus/2019-ncov/prevent-get-ting-sick/how-covid-spreads.html
4 Scientific Brief: SARS-CoV-2 and Potential Airborne Transmission, U.S. CDC, https://www.cdc.gov/coronavirus/2019-ncov/more/scientific-brief-sars-cov-2.html
5 COVID-19, How Does It Spread? ASL Video Series, U.S. CDC, https://www.youtube.com/watch?v=m4gborCUzt-k&list=PLvrp9iOILTQatwnqm61jqFrsfUB4RKh6J&index=7&t=0s
6 National Geographic, Science, Published Aug. 11, 2020, https://www.nationalgeographic.com/science/2020/08/how-to-measure-risk-airborne-coronavirus-your-office-classroom-bus-ride-cvd/
7 WHO, Transmission of SARS-CoV-2: implications for infection prevention precautions, https://www.who.int/news-room/commentaries/detail/transmission-of-sars-cov-2-implications-for-infection-prevention-precautions
8 ASHRAE Epidemic Task Force, Building Readiness, Sept. 30, 2020, https://www.ashrae.org/file%20library/technical%20resources/covid-19/ashrae-building-readiness.pdf
• Review Pandemic Preparedness and Response Plan regularly and keep it updated.
• Be aware that changing system settings and sequences of operation without a good understanding of the effects on system operation could result in unintended consequences. In order to ensure health and safety and to minimize the risk of damage to property and equipment, always consult with appropriate professionals before undertaking any project.
• Each building is unique. Therefore, it is important to understand the facility requirements, individual system requirements and operating conditions before undertaking any initiatives to alter the operating parameters of the building systems to help minimize transmission of the virus in the building.
• Involve building operations staff in the process in order ensure knowledge transfer between system experts and building operations staff.
Non-Mechanical StrategiesAccording to U.S. CDC, COVID-19 spreads very easily from person to person, and most commonly through close personal contact9. Best practices generally recommended by healthcare professionals include but are not limited to:
• Policies to promote the use of face masks, shields and other recommended facial coverings
• Policies to promote physical distancing between people as well as within work spaces, meeting areas, breakrooms, lobbies, elevators, etc.
• Policies to promote proper hand hygiene
• Policies for enhanced cleaning requirements
• Policies to limit building occupancy levels
• Control the direction of traffic within the building as well as in and out of the building
• Remove any objects that could help transmit the virus from the lobby or other areas where people typically congregate
• Use of approved contact-tracing apps and tools (with appropriate privacy protections)
• Use of approved temperature or thermal scanners (with appropriate privacy protections)
For more details on non-mechanical strategies to mitigate the transmission of COVID-19, refer to the Pathway Back to Work – Commercial Real Estate, Coronavirus & Re-Entry10, published by BOMA Canada.
General Practices 6
9 U.S. Centers for Disease Control and Prevention (CDC), https://www.cdc.gov/coronavi-rus/2019-ncov/prevent-getting-sick/how-covid-spreads.html
10 Pathway Back to Work – Commercial Real Estate, Coronavirus & Re-Entry, BOMA Canada, http://bomacanada.ca/wp-content/uploads/2020/06/Pathway-Back-To-Work-V2-EN-draft3-NR.pdf
These are best practices based on standards and guidelines from ASHRAE and other practitioners to help mitigate the spread of infectious aerosols through buildings’ HVAC systems.
• Changes to building systems require a holistic and systematic approach. Clearly define the objectives and expected outcomes.
• Risk assessment should include a thorough assessment of relevant equipment, systems and controls. Start with components, then move to systems, finally move to the building automation system (BAS) and integrated, whole building operations.
• Understand facility requirements and operational needs.
• Verify that HVAC controls (including remote monitoring, fans, dampers, alarms, etc.) are operable and are functioning properly to move air in and out of the building.
Mechanical Strategies 7
HVAC
1. Ventilation
a. Consider increasing outdoor air ventilation to reduce the recirculation of air back to the space. Consider 100% outside air, where possible and with no significant energy penalty; otherwise, maintain code-required ventilation and provide “Upgrading and Improving Filtration.” See below.
b. While 100% outside is preferable (subject to system and energy constraints), and is possible during warm seasons, in winter bringing in high percentage of outside air is not practical. According to ASHRAE the difference in risk level between 100% outside air and use of MERV-13 filter (or above) over time is marginally small. So under circumstance where high percentage of outside air is limited use minimum outside air per ASHRAE Standard 62.1 and provide a minimum MERV-13 filter11 (or above). Must always maintain code-required ventilation, and provide “Upgrading and Improving Filtration.” See below.
c. Maintain a relative humidity between 40% and 60%. Research indicates that this decreases the bio-burden of infectious particles in the space and decreases the ability of the virus in the air to infect12. Be mindful of potential condensation issues in winter.
d. Increase the quantity of outside air. Clean your cooling coil to recapture lost heat transfer from fouling. Studies indicate that dirty coils reduce the capability for heat transfer.
e. Open outside air intake dampers to their maximum to achieve three air changes, or, four hours minimum flush (2 hours each pre and post occupation). Operate the HVAC systems in “occupied” mode after completing the extended flush to allow the temperature and other indoor conditions to stabilize at set points. Check that the space’s temperature and relative humidity levels are being controlled to the acceptable set points.
e. During occupied times, set system to deliver at least three air exchanges of outside air.
f. Under regular operation, implement flush mode to operate the HVAC system to bring in maximum outside airflow where possible to achieve three air changes of outside air, or, for two hours before and after occupied times. Research shows that flushing the building for this duration will reduce the concentration of airborne infectious particles by 95%.
g. If the building could accommodate and subject to weather conditions, consider opening windows as an enhancement for outside air, especially when the system cannot accommodate MERV-13 filter or high percentage of outside air13.
h. Exhaust systems should run during the flush and occupied mode, two hours before and after occupied periods.
i. Review airflow inside spaces (lobby, elevators, stairwells, washrooms, conference rooms, offices, atriums). Ensure the air throw pathways do not blow on a person’s face and cascade on to others. Use portable air cleaners where movement of air may be slow or restricted.
Mechanical Strategies con’t 8
11 ASHRAE Building Readiness Guideline for additional details: https://www.ashrae.org/file%20library/technical%20resources/covid-19/ashrae-building-readiness.pdf
12 ASHRAE Epidemic Task Force – Commercial (Updated Aug 17, 2020) https://www.ashrae.org/file%20library/technical%20resources/covid-19/ashrae-commercial-c19-guidance.pdf
13 ASHRAE Technical Resources – Commercial: https://www.ashrae.org/technical-resources/commercial
Mechanical Strategies con’t 9
j. For VAV systems, provide a minimum MERV-13 filter for recirculation. Consider disabling demand control ventilation, if any.
k. Air handling systems should provide adequate airflow with no blockages in the duct system. Consider duct cleaning and disinfection per regular schedule with PPE to protect workers.
l. If a space has occupants after hours (e.g. cleaning crews, maintenance workers, construction workers, etc.), the space should be operated in the occupied mode including the operation of both supply and exhausts systems.
2. Upgrading & Improving Filtration
Air filtration plays an important role in minimizing the risk of transmitting infectious aerosols through the HVAC system. Therefore, consider improving the efficiency of the filters serving HVAC systems.
a. Mechanical filters are the most common types of filters found in HVAC systems. ASHRAE recommends that mechanical filter efficiency be at least MERV 13, MERV 14 or better. This can further reduce the viral load of aerosols. The higher the MERV number, the better the ability of a filter to remove particles from the air. Seal the edges of the filter to eliminate by-pass. It should be noted that filters with higher MERV numbers may require more frequent filter changes in the system in order to maintain the desired airflow.
b. After each filter replacement, make sure the air handling systems and fans can overcome the additional pressure drop of the new filters and still maintain airflow at acceptable levels.
3. Air Cleaning Technologies
It must be understood that there is no single technology that is 100% effective under different application scenarios. There are pros and cons for each technology, and landlords need to make informed decisions when choosing air filtration and air cleaning technologies for their buildings.
a. Understand the facility requirements and operating conditions for each building
b. Understand the inherent risks associated with each technology
c. Consider the installed efficiency vs designed efficiency
d. Many factors can impact the efficacy of air filtration and air cleaning technologies. These include:
> Building characteristics (location, type, use, etc.)
> Operating conditions
> Application
> Maintenance
e. Consider UVC light as an enhancement where spaces require additional measures
4. Building Pressure Control
Maintaining proper pressure within the building and spaces is an important consideration in minimizing the spread of infectious aerosols. Care should be taken when increasing outside air but keeping exhaust and relief air systems as designed. Otherwise, this change may lead to problems such as difficulties in keeping doors closed, reversal of pressure, noise, etc. Improper pressure may also impact other operational areas such as kitchens, washrooms and elevator shafts that are designed to be operated in negative pressure conditions.
a. Maintain equal pressures on all the floors. Maintain slightly positive pressure as compared to outside.
b. When pressuring buildings, account for stack effects and wind effects.
c. To maintain pressure, tenants and visitors should use revolving doors and properly designed vestibules where available, rather than using single swinging doors to enter the building.
Mechanical Strategies con’t 10
5. Maintenance
Proper maintenance is important to ensure that systems are functioning as designed and do not compromise the health and safety of occupants.
a. Ensure that all equipment and systems are maintained according to the schedule prescribed by the original equipment manufacturer (OEM). Where applicable, follow ASHRAE’s 180-2018, Standard Practice for Inspection and Maintenance of Commercial Building HVAC Systems.
b. Consider maintenance for cooling coils, heating coils, condensate drain pans and humidifiers inside air handling equipment per the building’s normal schedule.
c. Disinfect high-touch areas of HVAC and other building service systems e.g. on/off switches, thermostats, etc.
d. Use personal protective equipment (PPE) when maintaining ventilation materials, including filters and condensate. The same care should be exercised when handling and disposing of contaminated materials (vacuumed content, used filters, etc.).
e. Provide PPE for building operators, maintenance technicians and anyone else who must inspect or come in contact with HVAC devices or equipment.
Building Automation System (BAS)
Keeping systems running keeps the equipment and systems operational. Therefore, it is not recommended to completely shut off HVAC systems in a building that is being temporarily shut down or unoccupied for an undetermined amount of time. The intent is to maintain the building within a reasonable range of temperature and humidity conditions to help avoid developing poor indoor conditions while reducing energy consumption during the shutdown and also cause freezing or overheating conditions indoors .
a. Check important remote or offsite access connections to the Building Management System and BAS to make sure they are functioning properly.
b. If the building is empty, set the BAS to unoccupied temperature and humidity setbacks, and monitor and adjust to preserve IAQ and other health and life safety systems.
c. If occupants are permitted to use the building on a partial or limited basis during a shutdown, it may be desirable to program an override into the BAS. This will allow the systems to return temporarily to normal occupied modes of operations.
d. Before the building is operated under normal operating mode, check that the devices, sensors and controls are within an acceptable calibration for controlling space comfort and ventilation.
e. After the building is restarted and under normal operating mode, verify Occupied / Unoccupied sequencing, and check to see that building and space temperature and relative humidity levels are being controlled to the acceptable set points.
f. Consider an update to the programming to incorporate HVAC strategies to reduce virus transmission prior to future events. Automated control sequences applied as “Epidemic Mode” operations can be manually selected by the operator with one stroke.
g. Refer to the ASHRAE Building Readiness Guideline for additional details: https://www.ashrae.org/file%20library/technical%20resources/covid-19/ashrae-building-readiness.pdf
Mechanical Strategies con’t 11
Water & Plumbing SystemWhen buildings have been shut down for an extended period, water stagnates in the plumbing system and other mechanical systems. This creates an ideal condition for waterborne pathogens (like Legionella pneumophila) and other contaminants, and also leads to severe corrosion. Take proper care when shutting down and restarting buildings.
a. Follow recommended operations and maintenance procedures prescribed by the OEM or the water/environmental service provider. Where appropriate, follow ASHRAE’s standards and guidelines for managing risks associated with building water systems.
b. Keep heating water systems circulating and maintain temperatures above 140°F to avoid microbial incursion. Do not let water temperatures drop below 120°F.
c. Regularly turn on the water and run the drinking fountains, lavatories, urinals, water closets and sinks. Do this once a week or as needed to maintain a minimum disinfectant residual and avoid issues with stagnant water.
d. Refer to ASHRAE Building Readiness Guideline for additional details: https://www.ashrae.org/file%20library/technical%20resources/covid-19/ashrae-building-readiness.pdf
Mechanical Strategies con’t 12
Estimating the risk of airborne COVID-19 in an office setting.
The COVID-19 Aerosol Transmission Estimator14 is a model developed by Prof. Jimenez (Jimenez Group15) at the University of Colorado – Boulder. The research of the Jimenez Group centres on the development and application of advanced instrumentation for real-time, quantitative measurements of the chemical composition of submicron aerosols and gases.
This tool (a model) estimates the riskiness of different activities based on one potential route of coronavirus spread known as aerosols.
NOTE16: This model does not fully account for how your risk increases the closer you get to an infected
person, where the concentration of both aerosols and respiratory droplets will be higher. Potential
risk from contaminated surfaces is also not included. All scenarios assume constant values for room
temperature, pressure, humidity, and how quickly particles settle out of the air onto surfaces due to
gravity. The model also assumes that no one in the local population is immune.
This “slider” model is said to be applicable to offices as well. For example, enter 50 sf/person, which is almost impossible these days to be that dense, and everybody wears a mask. The efficiency of masks has to be fairly accurate, but let’s start with 70% (well below the efficiency of N95 masks) to determine the level of risk.
Fate and Transport of Indoor Microbiological Aerosols (FaTIMA17)
FaTIMA is a web-based tool developed by the National Institute of Standards and Technology (NIST18). FaTIMA can help estimate the indoor fate of microbiological aerosols associated with ventilation, filtration, deposition and inactivation mechanisms. It provides a representation of a single, well-mixed zone that is served by a mechanical ventilation system and incorporates particle source and removal mechanisms. Simulations can be run for a 24-hour period, with the results including the time history of the airborne concentration and surface loading as well as integrated exposure that an occupant might experience.
Special Tools 13
14 COVID-19 Aerosol Transmission Estimator, https://docs.google.com/spreadsheets/d/16K1OQkLD4BjgBdO8ePj6ytf-RpPMlJ6aXFg-3PrIQBbQ/edit#gid=519189277
15 Jimenez Group, http://cires1.colorado.edu/jimenez/
16 National Geographic, Science, Published Aug. 11, 2020, https://www.nationalgeographic.com/science/2020/08/how-to-measure-risk-airborne-coronavirus-your-office-classroom-bus-ride-cvd/
17 Fate and Transport of Indoor Microbiological Aerosols (FaTIMA), NIST, https://www.nist.gov/services-resources/software/fatima
18 National Institute of Standards and Technology, U.S. Department of Commerce, https://www.nist.gov/
Glossary of Terms 14Aerosol: It is a suspension of fine solid particles or liquid droplets in air.
Air Flush (or Flush): A process of purging the building of stale or potentially contaminated air in order to improve the indoor air quality.
Airborne Transmission: Airborne transmission is defined as the spread of an infectious agent caused by the dissemination of droplets (aerosols) that remain infectious when suspended in air over long distances and time.
Air Cleaning or Air purification: Air purification is the process of sanitizing the air by neutralizing airborne toxins (gases and off-gassing, bacteria, viral or fungal matter, toxic pathogens, etc.). Air purification uses a different method than an air filter to purify the air of toxins. Instead of simply trapping airborne particles within the mechanism of a tangible filter, an air purifier emits something to kill, neutralize, transform or otherwise render airborne toxins harmless.
Air Filtration: A process by which particulates in the air (dusts, mites, contaminants, etc.) are removed by forcing the air through a filtering medium. Particulates are “trapped” in the filter.
ASHRAE: American Society of Heating, Refrigeration and Air-conditioning Engineers
BAS: Building Automation System
BOMA: Building Owners and Managers Association
Designed Efficiency: The efficiency at which an equipment is designed to perform.
Heat Exchanger: A device that allows or enables transfer of heat from one medium to another or from one device to another.
Fouling: Accumulation of unwanted deposits on heat transfer surface of a heat exchanger.
HVAC: Heating, Ventilation and Air Conditioning
Infectivity: In epidemiology, infectivity is the ability of a pathogen to infect.
Installed Efficiency: The actual efficiency of the equipment once it is installed and in operation.
Interaction Effects: Where change made to one variable leads to combined effects of two or more variables acting together to produce an outcome that is more (or less) than the intended outcome.
MERV: Minimum Efficiency Reporting Value. It is a system used to evaluate the efficiency of an air filter based on how effective it is at catching particles of varying sizes.
OEM: Original Equipment Manufacturer
PPE: Personal Protective Equipment, as prescribed by healthcare practitioners and experts
Relative Humidity (RH): It is a measure of the moisture in the air, compared to the potential saturation level. Warmer air can hold more moisture.
Respiratory Droplet: is a small droplet produced by exhalation, consisting of saliva or mucus and other matter derived from respiratory tract surfaces.
SARS: Severe Acute Repertory Syndrome
Set Back: It refers to changing the temperature setting on the thermostat for a period of time when the space will not be occupied or require as much heating or cooling.
Set Point: It is the temperature you have “set” your thermostat to maintain.
Stack Effect: Stack effect is air movement caused by thermal differences. Higher-temperature air is less dense than cooler air. As the warmer air rises, it creates a pressure difference, with lower pressure below and higher pressure above.
VAV: Variable Air Volume. It is a type of heating, ventilating, and/or air-conditioning (HVAC) system. Unlike constant air volume (CAV) systems, which supply a constant airflow at a variable temperature, VAV systems vary the airflow at a constant temperature.
UVC: It refers to ultraviolet light with wavelengths between 200 – 280 nanometers (nm). Light in the UVC wavelength can be used for disinfecting water, sterilizing surfaces, destroying harmful micro-organisms in food products and in air.
Wind Effect: When the wind collides with the side of a building, different amounts of pressure are exerted upon different sides of the building. The side directly facing the wind experiences the highest force of air and as a result a higher air pressure.
Glossary of Terms Con’t 15
References & Resources 16
The following references and resources are provided to BOMA Toronto for the purpose of sharing with our audience. BOMA Toronto is not guaranteeing the validity, accuracy or application of information contained within these references and resources. Readers are urged to consult with their own advisors or contact the authors of the information directly for any clarification.
You will find that some of the articles have denoted with an asterisk (*). These are preliminary reports that have not undergone peer review. They should not be considered conclusive, used to inform clinical practice, or referenced by the media as validated information.
BOMA
1. Pathway Back to Work – Commercial Real Estate, Coronavirus & Re-Entry, BOMA Canada, http://bomacanada.ca/wp-content/uploads/2020/06/Pathway-Back-To-Work-V2-EN-draft3-NR.pdf
Building Reopening
1. ASHRAE Epidemic Task Force – Commercial (Updated Aug 17, 2020): https://www.ashrae.org/file%20library/technical%20resources/covid-19/ashrae-commercial-c19-guidance.pdf
2. ASHRAE Building Readiness for COVID-19 Reopening - Updated 9-30-2020: https://www.ashrae.org/file%20library/technical%20resources/covid-19/ashrae-building-readiness.pdf
Infectious Aerosols and HVAC Systems
2. ASHRAE Position Document on Infectious Aerosols – Published 4-14-2020: https://www.ashrae.org/file%20library/about/position%20documents/pd_infectiousaerosols_2020.pdf
3. U.S. Centers for Disease Control and Prevention (CDC), https://www.cdc.gov/coronavirus/2019-ncov/prevent-getting-sick/how-covid-spreads.html
4. COVID-19, How Does It Spread?, ASL Video Series, U.S. CDC, https://www.youtube.com/watch?v=m4gborCUztk&list=PLvrp9iOILTQatwnqm61jqFrsfUB4RKh6J&index=7&t=0s
5. ASHRAE Epidemic Task Force – Scientific Data Committee (Updated Apr. 17, 2020): https://www.ashrae.org/file%20library/technical%20resources/covid-19/ashrae-scientific-c19-guidance.pdf
6. ASHRAE Scientific Resources: https://www.ashrae.org/technical-resources/ashrae-scientific-resources
7. Identification of SARS-CoV-2 RNA in Healthcare Heating, Ventilation, and Air Conditioning Units https://www.medrxiv.org/content/10.1101/2020.06.26.20141085v1 *
8. Mechanistic Transmission Modeling of COVID-19 on the Diamond Princess Cruise Ship Demonstrates the Importance of Aerosol Transmission: https://www.medrxiv.org/content/10.1101/2020.07.13.20153049v1 *
9. Aerosol and surface contamination of SARS-CoV-2 observed in quarantine and isolation care: https://www.nature.com/articles/s41598-020-69286-3
10. Viable SARS-CoV-2 in the air of a hospital room with COVID-19 patients (Healthcare-specific air sampling): https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7418726/ *
11. Can Air-Conditioning Systems Contribute to the Spread of SARS/MERS/COVID-19 Infection? Insights from a Rapid Review of the Literature: https://www.mdpi.com/1660-4601/17/17/6052/htm
12. Airborne route and bad use of ventilation systems as non-negligible factors in SARS-CoV-2 transmission (Poor ventilation and airborne transmission): https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7182754/
References & Resources Con’t 17
13. Review of indoor aerosol generation, transport, and control in the context of COVID‐19 (Indoor aerosol generation – overview with diagrams): https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7405119/
14. SARS-CoV-2 in the environment: Modes of transmission, early detection and potential role of pollutions (SARS-CoV-2 in the environment, modes of transmission): https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7361046/
15. Airborne transmission of severe acute respiratory syndrome coronavirus‐2 to healthcare workers: a narrative review (Healthcare-specific re. aerosol-generating medical procedures; explainers): https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7264768/
16. Air and environmental sampling for SARS-CoV-2 around hospitalized patients with coronavirus disease 2019 (COVID-19) (Contrary evidence: no aerosol transmission with 12 air-changes per hour): https://pubmed.ncbi.nlm.nih.gov/32507114/
Ventilation
1. Effects of personalized ventilation interventions on airborne infection risk and transmission between occupants (Personalized ventilation interventions): https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7260576/
Air-Cleaning Technologies
1. Air Cleaning Technologies - An Evidence-Based Analysis (2005): https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3382390/
2. Airborne SARS-CoV-2 is Rapidly Inactivated by Simulated Sunlight; https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7313838/
3. COVID-19 (Corona Virus) and Air Filtration Frequently Asked Questions (FAQs): https://www.nafahq.org/covid-19-corona-virus-and-air-filtration-frequently-asked-questions-faqs/
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BOMA Toronto does not represent, warrant or guarantee that this review of best practices includes any and all best practices that may be necessary in order to mitigate the risk of COVID-19 transmission or increase indoor air quality in any particular circumstances.
Disclaimer 18
For additional information please contact:Bala Gnanam, VP - Energy, Environment & [email protected]
bomatoronto.org
On behalf of our membership we would like to thank all the Council members for volunteering their time and sharing your expertise and insights to help us with this important mission.
Building HVAC Operational Best Practices
Advancing Better Indoor Air Quality in the Age of COVID-19
Updated October 14, 2020