In order to comply with Indoor Environmental Quality Credit, Enhanced Indoor Air Quality Strategies, Option 2. Additional Enhanced IAQ Strategies Calculator A all entrances to the building must have entryway systems 10 ft. (3 m) long in the direction of travel B COz monitors must be fitted in all densely occupied spaces and configured to provide an alert all outdoor air supply systems must have an airflow measurement device that measures at least 90% of the airflow D all particle filters in the ventilation system must meet Comit Europen de Normalisation (CEN) standard Class F7 or better