C403.8.4 Fractional HP Fan Motors (Mandatory)
Motors for fans that are not less than 1/12 hp (0.062 kW) and less than 1 hp (0.746 kW) shall be electronically commutated motors or shall have a minimum motor efficiency of 70 percent, rated in accordance with DOE 10 CFR 431. These motors shall have the means to adjust motor speed for either balancing or remote control. The use of belt-driven fans to sheave adjustments for airflow balancing instead of a varying motor speed shall be permitted.
Exceptions: The following motors are not required to comply with this section