The safety of our staff and our students is our priority. Our safety expectations and plan are based on current guidance from local, state and federal public health agencies.
Here is what we are doing to address ventilation in our schools.
This is a video recording of the April 2 staff webinar about air quality and ventilation in our school buildings and mitigation measures to ensure ventilation meets COVID safety standards.
- How often are the filters in air exchange units changed or cleaned?
- Some older HVAC systems have metal filters. How are those maintained?
- How was air exchange measured in classrooms?
- How are air exchange requirements calculated?
- Some older HVAC systems are noisy. With social distancing and masks, students’ voice will be hard to hear. What is being done to address this?
- Has anything been done to mitigate toilet plumes from when the toilet is flushed?
- Do you have a ventilation question that is not answered here?
Ventilation in all buildings meets or exceeds CDC recommendations for ventilation in schools. In older schools where HVAC systems do not meet the standards, occupied rooms have been equipped with supplemental air filtration systems.
The CDC recommends fresh air supply of 20 cubic feet per minute (cfm) per person. The CDC standard assumes 25-30 students in a 980 square foot classroom. In hybrid, we have about half the recommended number of students per classroom, resulting in fresh air supply of 40 cfm per person, effectively exceeding the standard by double in most classrooms.
Per CDC and Washington State Department of Health (DOH) recommendations, our systems provide a minimum of four to six air exchanges per hour, and in many cases up to 12 air exchanges per hour. Air exchange systems run two hours before and two hours after school hours to ensure fresh and filtered air before school starts.
Air handler maintenance and filter changes are being done on an accelerated cycle that exceeds manufacturer-recommended change intervals.
Our professionally trained facilities team has completed an audit of HVAC systems in elementary school buildings and is in the process of completing audits in secondary schools. Completed audits verify that:
- All air handling units are operable and functioning appropriately.
- Supply and exhaust fans are operating at increased rates.
- Fresh air intakes have been adjusted to add maximum intake of fresh air into building air circulation.
- All vent airways are unobstructed.
- All thermostat and actuator controls are functioning at or above manufactured performance level.
- HVAC filter ratings have been upgraded throughout the district to the maximum system capacities.
Any deficiencies are on track to be corrected by April 19.
In some older buildings that do not have central HVAC systems, classrooms that do not meet air quality recommendations are being equipped with portable air filtration machines.
Opening windows and outside doors can increase circulation and air quality, but this is not necessary to meet CDC standards in rooms with supplemental air filtration or modern HVAC systems. In buildings constructed after 2000, opening doors and windows can actually reduce the effectiveness of air filtration systems; however, opening doors and windows will not bring a room below CDC standards.