Tetra Tech’s Industrial Hygiene Sciences Group provides comprehensive quantitative assessments to support COVID-19 risk management decisions for return to work and occupancy of office, warehouse, and manufacturing workspaces.
Our quantitative assessment services include exposure evaluation, risk of infection determination, control technology performance modeling, and field testing for validation of control technology effectiveness.
Exposure Evaluation and Risk of Infection
- Evaluation of workspace occupancy patterns based on modeled or monitored uses of the workspace
- Determination of risk (probability) of infection for virus transmission and worker exposure scenarios using scientifically recognized mass-balance stochastic (Monte Carlo) mathematical models, the most current respiratory deposition, and infectivity information for the SARS-CoV-2 virus
Control Technology Effectiveness Evaluation
- Computational fluid dynamic (CFD) modeling for indoor air dispersion in support of control technology evaluation
- Evaluation of the baseline risk of infection for current or proposed ventilation system designs in specific areas within the workspace environment
- Evaluation of the effectiveness in reducing the risk of infection for various control technologies such as high-efficiency filtration, ultraviolet germicidal irradiation, and bipolar ionization, including stochastic (Monte Carlo) analysis of control parameters
- Evaluation of the feasibility of layering one more control technologies on existing HVAC systems in support of selecting control technologies to provide an acceptable level of health protection at the design stage
Testing and Validation
- Physical testing and validation of model results using techniques such as:
- Virus-size particle generation and measurement upstream and downstream of filtration controls
- Physical and mechanical measurements for non-filtration control equipment
- Surrogate testing (e.g., carbon dioxide) for dilution verification