Building Airflow Standard Chart  
                   
Volume of habitable space   cubic feet  
                   
Occupants (bedrooms +1)   occupants
                   
Climate Zone   zone  
                   
Height Correction Factor   factor  
# of stories Height Correction Factor    
1 1    
1.5 0.89    
2 0.81    
2.5 0.76    
3 0.72    
                   
"N" Factor    
  climate zone multiplied by height correction factor   "N" factor  
                   
Building Airflow Standard - Use Greater of Two Methods    
                   
  1. ((15cfm * # occupants) * “N”) = CFM50   CFM50  
                   
      CFM50  
  60                
              BAS  
                   
            House CFM50  
                   
If final house CFM50 is greater than BAS, no work needs done    
                   
Final house CFM 50 between 70% and 100% of BAS, mechanical ventilation recommended  
                   
Final house CFM50 less than 70% of BAS, mechanical ventilation required, see below  
                   
Minimum Mechanical Ventialtion Rate - Greater of Two Methods    
  (15cfm * # of occupants)   cfm  
                   
  (.35 ACH * Volume)   cfm  
  60                
                   
            Minimum mechanical ventilation requried (larger of above) cfm  
                   

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