Bellevue School District has developed ventilation standards for all buildings in the District, based on ASHRAE (American Society of Heating, Refrigerating and Air-Condition Engineers) Re-Opening Guide for Schools.

For ventilation and air circulation we are layering multiple protective strategies including:

  • Increased outside air (ventilation) to each zone to the maximum allowed by the system. Goal will be to exceed rates required by Washington State and ASHRAE. Air is changed over 6.6 – 8.8 times per hour with outside air.
  • Disabled energy saving control functions that would reduce outside air exchange.
  • Ventilation systems and controls that can be monitored and adjusted over the district network.
  • Monitor ventilation systems and controls remotely including carbon dioxide levels which are used as an indicator for fresh air circulation.
  • Operate ventilation systems in occupied mode for one week prior to occupancy.
  • Operate ventilation systems 2 hours before and 2 hours after occupancy.
  • Matching student cohorts to ventilation zones to minimize cross contamination.
  • Using MERV 13 filters that are efficient at capturing airborne viruses and changing them at least once every three months.

What is being done to increase ventilation in classrooms and school hallways?

Systems in all BSD schools have been set to pull in air from outside. District buildings have multiple layers of MERV 8-13 filters in place that are changed every three months. Our ventilation systems are fully commissioned and continuously monitor carbon dioxide levels with sensors as a measure of ventilation.

Do Bellevue schools have air filtration systems in place, such as HEPA or MERV-13?

The district does not have HEPA filters in our HVAC system. We use Tri-Dex 2 ply to 4 ply filters which range from MERV 8-13. Occupied spaces are filtered multiple times by different equipment, such as Heat Pumps, DOAS (Dedicated Outside Air Supply) and Heat Recovery Units. Our filters are changed every three months.

The Bellevue School District acknowledges that we learn, work, live and gather on the Indigenous Land of the Coast Salish peoples, specifically the Duwamish and Snoqualmie Tribes. We thank these caretakers of this land, who have lived and continue to live here, since time immemorial.