ANSI/ASHRAE/IES Standard 62.1-2019 
Ventilation for Acceptable Indoor Air Quality

(Supersedes ANSI/ASHRAE Standard 62.1-2016)

The revised 2019 edition of the standard includes significant changes, including:

  • New informative tables of ventilation rates per unit area for checking new and existing buildings ventilation calculations
  • Simplified version of the Ventilation Rate Procedure improving calculations for system ventilation efficiency and zone air distribution effectiveness
  • Modified Natural Ventilation Procedure calculation methodology
  • Revised scope to specifically identify occupancies previously not covered


  • Natural ventilation now requires considering the quality of the outdoor air and interaction of the outdoor air with mechanically cooled spaces.
  • Humidity control requirements are now expressed as dew point and not as relative humidity.


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