Making Classroom Air Safer During the Pandemic: A Step-by-Step Path to Optimal Air Changes for COVID-19 Mitigation

Published 12/01/2020
By Doug Engel
How to Achieve 5 Air Changes per Hour (ACH) in Classrooms enVerid Systems

Experts recommend at least 5 total air changes per hour (ACH) for classrooms to help ensure the safety of students, teachers and staff during the pandemic. This means the air inside a classroom will be exchanged with clean air once every 12 minutes.

There are two ways to achieve this:

  1. Air changes from outdoor ventilation – can be mechanical (HVAC system) or natural (open windows or doors); or
  2. Air changes from recirculated air that is cleaned – can be done by filtering air centrally by the HVAC system or using in-room fixed or portable HEPA air cleaners

These approaches can be additive, meaning that schools may rely on a combination of methods to achieve the target ACH in the classroom. For example, outdoor air ventilation of 1 ACH + air cleaning of 4 ACH = the target of 5 ACH.

The following decision tree provides an easy way for schools to determine the most direct path to achieve 5 ACH in each classroom.

How to Achieve 5 Air Changes per Hour (ACH) in Classrooms enVerid SystemsThis decision tree is one of the useful tools included in enVerid Systems’  free resource for school administrators and facility managers to help them navigate the most effective path to improving classroom air quality. The guide, entitled “The Definitive Guide to Improving Classroom Air Quality for COVID-19 Mitigation” answers key questions about IAQ in the classroom and provides easy-to-implement recommendations to reduce the risk of airborne virus transmission, including COVID-19, in schools.

Download the free guide to learn more about COVID-19 mitigation in the classroom.

Doug Engel

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