Posted on January 31, 2021
Categories: News from SDP

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Proper ventilation in our schools is one of the layers of safety that will be in place in all of our school district buildings as we prepare to phase students back to in-person learning. Certified ventilation experts have tested nearly every room in every school district building to assess air flow. This is an unprecedented effort in our District, and likely the most comprehensive effort being done by any large public school district in the country. Information about our ventilation efforts can be confusing and there is also a lot of false information out there. Here are the facts about what we have done and will continue to do to support healthy air flow in our schools.

Fact #1: Fresh Air Flow Matters 
Fresh air flow improves air quality by reducing the amount of contaminants in the air and supporting a healthier breathing environment. Fresh air can be supplied by a mechanical building ventilation system (HVAC) or through a window fan.The recommended standard for fresh air flow is 15 cubic feet per minute per person.* Healthy air flow is an important layer of safety in addition to wearing masks, social distancing, frequent handwashing and other safety precautions.

*Standard set by the American Society of Heating, Refrigeration and Air-Conditioning Engineers.

Fact #2: Air Balance Testing Works
Air Balance Testing is the industry standard for determining the amount of outside air that is flowing through a room every minute. The Philadelphia Federation of Teachers union endorsed this testing as part of our comprehensive plan to resume in-person learning.

Fact #3: Certified Air Balancers Conducted All Testing
These professionals have four to eight years of test and balance experience, based on education, and have successfully passed a rigorous, eight-hour written examination that tests their knowledge and technical competence in air and hydronic systems balancing, including fan and pump laws.

Fact #4: Ventilation Test Results Have Been Used to Inform Safe Occupancy Levels for Every Room
Air balance tests identified the amount of fresh air flow in the room in cubic feet per minute (CFM). That number was divided by the recommended standard per person of 15 cfm to determine the safe occupancy level in that room, before social distancing requirements are applied. (Example: if the test measured 300 cfm in the room, 300 divided by 15 means a maximum of 20 people could safely occupy the space.) Social distancing requirements are then applied to determine the safe occupancy level posted on the sign outside of the room.

Fact #5: One of three things will happen if a room was initially determined to have no fresh air flow and showed a zero on the ventilation report:

  1. Option 1: If the room has a ventilation system needing a minor repair, the repair will be made and a new air balance test will be conducted to measure air flow and inform safe occupancy levels. Updated results will be added to the online report.
  2. Option 2: If there is no ventilation system but at least one window in the room, a window fan will be installed to promote fresh air flow and temperatures in the room will be monitored. See this Window Fan Installation video. The three models of fans purchased each have the amount of air flow it generates printed on them by the manufacturer. We have taken the extra precaution of measuring the airflow of the fans with an air balancer to ensure that the rating is correct as noted by the manufacturer. We will also conduct new air balance testing in rooms with fans to inform the safe occupancy signs outside of the room. Updated results will be added to the online report.
  3. Option 3: If the room has a ventilation system needing a major repair and no window, the room will be taken offline and will not be used for person-to-person instruction until the repair is made.

Fact #6: Results from Air Balance Tests By School are Publicly Available Online
Reports for all schools are posted online here and are being updated daily as new reports are submitted by the certified air balancers.When it comes to safely returning to in-person teaching and learning, the safety of our students and staff is our highest priority. The Pennsylvania and Philadelphia Departments of Health and the Centers for Disease Control have consistently emphasized the importance of having multiple layers of safety — such as mandatory mask wearing, social distancing, and frequent hand washing — in place to protect everyone’s health and well-being during this COVID-19 pandemic. The science is clear that when these layers of safety are in place, the risk of transmission is significantly reduced. The District takes very seriously the responsibility to put these proven safeguards in place in every school, and we have done just that and more. These layers of safety include:

  • extensive health and safety protocols,
  • pre-screening protocols in place for students and adults,
  • inventories of PPE for staff and students to support mandatory mask wearing and facial covering while in schools,
  • new classroom and bathroom setups to ensure social distancing,
    plexiglass partitions in offices,
  • touchless hand sanitizer stations in all hallways,
  • cleaning supply stations in classrooms,
  • maximum occupancy signs outside each room and safety signage throughout,
  • enhanced cleaning protocols using EPA-approved cleaning products, and
  • touchless hydration stations  in hallways so water access is hands free.

To learn more about our ventilation efforts and all of our safety plans to protect the health and well-being of everyone in our schools, please visit There you’ll find these Supporting Clean and Healthy School Environments, Safe Return to School and Ventilation Assessments videos and other helpful videos, FAQs and resources to help you know the facts.