Facility Infection Risk Estimator v2.1
A Module from
BranchPattern’s
happē tool
USER GUIDE. This module is compatible with all browsers except Microsoft Explorer 11. The information provided in this user guide is intended to supplement the instructions given in the information bubbles associated with module’s input and output.
BranchPattern’s Facility Infection Risk EstimatorTM module is intended to estimate a) the aerosol viral particle removal efficiency resulting from several different removal mechanisms and b) the associated probability of infection for adults and children, given a set of input conditions including space parameters, demographic factors, and time.
This module is one component of our Health and Productivity Performance Estimator (happēTM) tool. The initial version of the tool was developed in 2009 to estimate the impact various indoor environmental quality (IEQ) conditions have on productivity and health. Based on IEQ peer reviewed research, it provides both percentage impacts and dollar amounts using weighted average salary dollars.
BranchPattern uses happēTM as part of pre- and post-occupancy evaluations to assess the impacts that existing space conditions are having on occupants. It’s also used during retrocomissioning and design to assess the relative impacts of different energy conservation measures (ECMs) or system types on productivity and health. BranchPattern has also found that making life cycle cost analyses more comprehensive increases the likelihood for sustainable and health/wellness focused decision-making throughout the design/construction process.
Summary of Changes to v2.1 of the Facility Infection Risk EstimatorTM
- Mask selections have been updated to reflect ongoing changes to the types of mask technology available and new research/testing of effective mask efficiencies.
- Vaccination for SARS-CoV-2 is now included for adults.
New variants of SARS-CoV-2 continue to evolve and spread within our communities. Research regarding the degree of infectiousness, mortality risk and resistance to vaccines of these variants is ongoing. For the following variants, we recommend multiplying the probability of infection results by the factors indicated. As new information becomes available we will update this recommendation.
- UK Variant: Data indicates increased infectiousness from 1.4 to 1.7. We have been using 1.5.
- Delta Variant: Data indicates increased infectiousness from 2.0 to 3.0. We have been using 2.5.
- Omicron BA.1 Subvariant: This impacts both the degree of infectiousness and the effectiveness of the vaccine. Multiply the probability of infection results from the calculator by the following: (8-(3.84*% Boosted))/(1-(0.8*% Boosted))
- Omicron BA.2 subvariant: This impacts both the degree of infectiousness and the effectiveness of the vaccine. Multiply the probability of infection results from the calculator by the following: (10.4-(4.68*% Boosted))/(1-(0.8*% Boosted))
This module was initially peer reviewed by Josephine Lau, Ph.D., Associate Professor of Durham School of Architectural Engineering and Construction, University of Nebraska – Lincoln. Dr. Harmon has subsequently co-authored a peer reviewed paper with Dr. Lau on the tool, available here: https://doi.org/10.1177/1420326X211039544.
Tutorial Videos:
What’s New in Facility Infection Risk Estimator, Version 2
County Case Numbers – Risk Factors
Figuring Out Your CFM Numbers
Case Study: K-12
Case Study: Cafe Dining
| Adult Risk Impact Summary | |
|---|---|
| Estimated Baseline Number of Adults Infected / Room*Day |
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| Estimated Design Number of Adults Infected / Room*Day |
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| Estimated Decrease in Adults Infected / Room*Day |
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| Estimated Baseline Number of Adults Infected / Viral Season |
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| Estimated Design Number of Adults Infected / Viral Season |
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| Estimated Decrease in Adults Infected / Viral Season |
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| Estimated Baseline Salary Dollars Directly Lost / Viral Season |
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| Estimated Design Salary Dollars Directly Lost / Viral Season |
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| Estimated Decrease in Salary Dollars Directly Lost / Viral Season |
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| Child Risk Impact Summary | |
|---|---|
| Estimated Baseline Number of Children Infected / Room*Day |
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| Estimated Design Number of Children Infected / Room*Day |
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| Estimated Decrease in Children Infected / Room*Day |
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| Estimated Baseline Number of Children Infected / Viral Season |
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| Estimated Design Number of Children Infected / Viral Season |
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| Estimated Decrease in Children Infected / Viral Season |
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| Estimated Baseline Child Days Lost / Viral Season |
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| Estimated Design Child Days Lost / Viral Season |
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| Estimated Decrease in Child Days Lost / Viral Season |
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| Adult Probability of Infection | |
|---|---|
| Design Pinfection-settling Per Day |
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| Design Pinfection-ventilation Per Day |
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| Design Pinfection-filtration Per Day |
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| Design Pinfection-RHinactivation Per Day |
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| Design Pinfection-UVGIinactivation Per Day |
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| Design Pinfection-PAC Per Day |
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| Design Pinfection-mask Per Day |
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| Design Pinfection-total Per Day |
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| Baseline Pinfection-total Per Day |
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| Estimated Decrease in Pinfection-total Per Day Compared to Baseline |
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| Design Pinfection-total Per Viral Season |
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| Baseline Pinfection-total Per Viral Season |
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| Estimated Decrease in Pinfection-total Per Year Compared to Baseline |
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| Child Probability of Infection | |
|---|---|
| Design Child Pinfection-settling Per Day |
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| Design Pinfection-ventilation Per Day |
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| Design Pinfection-filtration Per Day |
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| Design Pinfection-RHinactivation Per Day |
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| Design Pinfection-UVGIinactivation Per Day |
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| Design Pinfection-PAC Per Day |
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| Design Pinfection-mask Per Day |
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| Design Pinfection-total Per Day |
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| Baseline Pinfection-total Per Day |
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| Estimated Decrease in Pinfection-total Per Day Compared to Baseline |
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| Design Pinfection-total Per Viral Season |
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| Baseline Pinfection-total Per Viral Season |
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| Estimated Decrease in Pinfection-total Per Year Compared to Baseline |
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| Aerosol Viral Particle Removal Efficiency Output | |
|---|---|
| Design Settling Efficiency (Esettling) |
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| Design Ventilation (Outdoor Air) Efficiency (Event) |
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| Design Filtration Efficiency (Efiltration) |
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| Design RH Inactivation Efficiency (ERHinactivation) |
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| Design UVGI Inactivation Efficiency (EUVGIinactivation) |
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| Design Portable Air Cleaner Efficiency (EPAC) |
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| Design Mask Efficiency (Emask) |
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| Design Total Efficiency (Etotal) |
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| Baseline Total Efficiency (Etotal) |
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| Hypothetical R Value | |
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| Hypothetical Baseline R Value |
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| Hypothetical Design R Value |
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Disclaimer
This module was developed by employees of BranchPattern and is being made available for public use. The studies and models used for this module (referenced below) are based primarily on a) Influenza (in general and Influenza A in particular) and b) what we know as of 09/01/2020 for SARS-CoV-2. Influenza output is therefore most relevant to Influenza A but general interpretations could be made relative to Influenza B. Interpretations of output for SARS-CoV-2 should be made with the recognition we still have much to learn about SARS-CoV-2 and the resulting COVID-19 illness.
Also note that the mathematical models used by this module represent a simplified version of reality. The Facility Infection Risk EstimatorTM is designed to act as a simple heuristic for comparing the relative impacts from a baseline and design set of conditions. It is important that the user be aware of these simplifications, and that actual removal efficiencies and probabilities of infection will vary from the results given in this module. The results are intended to supplement, not replace, the judgement of qualified individuals competent in the knowledge domains of mechanical engineering, industrial hygiene, indoor air quality, infection control, and particle/pathogen airborne transmission.
The module is provided ‘as is’ without any warranty of any kind, either express, implied, or statutory, including, but not limited to, any warranty that the module will conform to specifications, any implied warranties of merchantability, fitness for a particular purpose, and freedom from infringement, and any warranty that the documentation will conform to the module, or any warranty that the module will be error-free. In no event shall BranchPattern be liable for any damages, including, but not limited to, direct, indirect, special or consequential damages, arising out of, resulting from, or in any way connected with this module, whether or not based upon warranty, contract, tort, or otherwise, whether or not injury was sustained by persons or property or otherwise, and whether or not loss was sustained from, or arose out of the results of, or use of, the module provided hereunder.
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