Safety fan

means:

(1) a reversible axial fan in cylindrical housing that is designed and marketed for use in ducted tunnel ventilation that will reverse operations under an emergency ventilation condition;

(2) a fan for use in explosive atmospheres tested and marked according to ISO 80079-36:2016, Explosive atmospheres -- Part 36: Non-electrical equipment for explosive atmospheres -- Basic method and requirements;

(3) an electric-motor-driven-Positive Pressure Ventilator as defined AMCA 240-15; or

(4) fans complying with ANSI/UL 705 (August 23, 2021) Standard for Safety for Power Ventilators and listed as “Power Ventilators for Smoke Control Systems; or

(5) a laboratory exhaust fan designed and marketed specifically for exhausting contaminated air vertically away from a building using high-velocity discharge.