School ventilation

September 2021 - Last evening (September 20, 2021) on KING 5, there was an investigation report regarding statewide K-12 school HVAC systems. In their investigation, data from the Washington Office of Superintendent of Public Instruction (OSPI) shows that nearly 800 school buildings across the state have “poor” ratings for their heating, ventilation, and air conditioning (HVAC) systems. The data used to create the report was self-submitted by school districts. Snohomish School District submitted its data during the 2018-2019 school year. Districts submit scores regarding their heating systems, HVAC distribution and ventilation. We are unaware how KING 5 formulated its database and overall scores using those three data points.

Specifics regarding Snohomish School District
Many of the Snohomish School District schools identified in the KING 5 report (as “poor”) have upgraded their HVAC control systems since the 2018-2019 report. The district has also installed better filtration in keeping with health and engineering expert recommendations and has adjusted the HVAC systems across the district to maximize the amount of fresh air from the outside. Specifically:

  • We have upgraded all filters to MERV 13 filters.
  • Rooms that lack proper ventilation have received portable air purifiers that have HEPA filters and air exchange of 500 square feet in 30 minutes.
  • Air exchange rates meet the recommendations from ASHRAE (American Society of Heating, Refrigerating and Air-Conditioning Engineers).
  • Systems are set to bring in 100% outside air as outside temperatures allow.
  • Schools receive an evening flush out of room air and replaced with fresh air. The amount of fresh air is modulated as temperatures drop during the winter months.