How does Sefaira Size AHU Design Airflow? 

There is only one air handling unit for the building. Its size is based on the "Design Air Flow" where:

Design Air Flow (AHU) = Sum of Design Air Flows (zone)

Where,

Design Air Flow (Zone) = Whichever is the greatest of either (Outside air per person + Outside air per unit floor area) OR (Total air changes)

Note

This means that although these inputs are in the same place they are not selecting one of the three or summing all three together.

• Outside air per person
• Outside air per unit floor area
• Total air changes

are the 3 items under Ventilation in the "Internal Conditions" tab.

Previously

Design Air Flow = (value input by user in l/s/m2) x (building area)