COVID-19 Recovery Office Building Ventilation Recommendations.

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Last week, CDC published new COVID-19 recommendations for office buildings. TAG believes the recommendations are essential to ensure employee safety and further recommends employers consult with an HVAC (heating, ventilation, and air conditioning)/ventilation expert on steps to improve ventilation in the building, which include:

• Increase the percentage of outdoor air (e.g., using economizer modes of HVAC operations) potentially as high as 100%. It will be necessary to first verify compatibility with HVAC system capabilities for both temperature and humidity control as well as compatibility with outdoor/indoor air quality considerations.

• If possible, increase the total airflow supply to occupied spaces.

• Disable demand-control ventilation (DCV) controls that reduce air supply based on temperature or occupancy.

• When environmental conditions and building requirements allow, consider using natural ventilation (i.e., opening windows if possible and safe to do so) to increase outdoor air dilution of indoor air.

• Improve central air filtration:

  • Increase air filtration to as high as possible (MERV 13 or 14) without significantly diminishing design airflow.

  • Inspect filter housing and racks to ensure appropriate filter fit.

  • Check for ways to minimize filter bypass.

• Consider running the building ventilation system even during unoccupied times to maximize dilution ventilation.

• Generate clean-to-less-clean air movement by re-evaluating the positioning of supply and exhaust air diffusers and/or dampers and adjusting zone supply and exhaust flow rates to establish measurable pressure differentials. Have staff work in areas served by “clean” ventilation zones that do not include higher-risk areas such as visitor reception or exercise facilities (if open).

 

Employers should also consider:

• Using portable high-efficiency particulate air (HEPA) fan/filtration systems to enhance air cleaning (especially in higher risk areas).

• Ensuring exhaust fans in restroom facilities are functional and operating at full capacity when the building is occupied.

• Using ultraviolet germicidal irradiation (UVGI) as a supplement to help inactivate the virus.