ASHRAE 62.1-2025 ✓ Most Recent

ASHRAE Standard 62.1 specifies minimum ventilation rates for acceptable indoor air quality, minimizes adverse health effects, and protects the integrity of buildings and ventilation systems. A properly designed and maintained ventilation system reduces the risk of mold, mitigates against the spread of nuisance and health hazards in the building, and contributes to occupant comfort and satisfaction.

The 2025 edition of the standard refines and expands the humidity control requirements, adds requirements for emergency ventilation controls to address atypical operating modes, and provides several new methods of calculation. Users of previous editions will find new methods for the calculation of separation distances between outdoor air intakes and exhausts; a new air density correction factor for all ventilation zones; a new method for calculating systems ventilation requirements when multiple standards are followed; a new demand control ventilation control sequence; requirements for air-cleaning system performance, including a calculation for end of useful life efficiency for certain contaminants; and revisions to the performance path for exhaust systems. Also included are updates to provide greater clarity of existing requirements and to align requirements with other codes and standards.