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

Standard Scope

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.

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