AHRI 640 (I-P) and 641 (SI): Performance Rating of Commercial and Industrial Humidifiers

This standard applies to factory-made commercial and industrial humidifiers, as defined in Section 3 of this standard.

• Energy Source. This standard applies to electric, gas, or hot water operated commercial and industrial humidifiers, including those that utilize steam from a central steam boiler.


• Installation. Commercial and industrial humidifiers are intended for central air systems or direct, in-space applications, and may be installed in a mechanical room or outdoors.

AHRI 640 (I-P/2017): Performance Rating of Commercial and Industrial Humidifiers

AHRI 641 (SI/2017): Performance Rating of Commercial and Industrial Humidifiers

© 2017, by Air-Conditioning, Heating, and Refrigeration Institute