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A Tool to Model Virus Particle Exposure in Residences (ViPER)



Stephen Zimmerman, Brian Polidoro, Lisa Ng, William Stuart Dols, Steven Emmerich


Virus Particle Exposure in Residences (ViPER) is a web-based, single zone indoor air quality and ventilation analysis tool developed by the National Institute of Standards and Technology (NIST) for evaluating an occupant's relative exposure to virus-laden particles exhaled by a temporary, contagious visitor inside a dwelling (i.e., subsequently referred to as the home). This tool is specifically designed for use in a residential environment. When an occupant (the home's resident) anticipates having a visitor (a potential, temporary and continuous source of virus-laden particles), this tool can be used to vary a set of input parameters and then compare the changes to either particle concentration or integrated exposure. Some such parameters include home size, visit duration, and portable air cleaner effectiveness, as well as mechanical ventilation rates and heating, ventilating and air-conditioning system operation strategies. This tool is based on a database of 1,296 CONTAM simulation results. CONTAM is a multizone indoor air quality and airflow analysis program developed by NIST. ViPER allows users to compare a "base" scenario meant to represent their home against multiple "what-if" scenarios meant to mitigate their exposure to virus-laden particles. ViPER is available, along with CONTAM and other NIST-developed software, on the NIST Multizone Modeling Website….
Technical Note (NIST TN) - 2211
Report Number


airflow, CONTAM, , contaminants, occupant exposure, simulation, residential, virus-laden particles


Zimmerman, S. , Polidoro, B. , Ng, L. , Dols, W. and Emmerich, S. (2022), A Tool to Model Virus Particle Exposure in Residences (ViPER), Technical Note (NIST TN), National Institute of Standards and Technology, Gaithersburg, MD, [online],, (Accessed April 22, 2024)
Created March 9, 2022, Updated November 29, 2022