Unvented room
heaters, unvented infrared heaters, and unvented decorative
appliances shall not be installed in any dwelling or occupancy.
Exception: Unvented infrared heaters may be installed
when mechanical ventilation is provided to exhaust at least 4
cubic feet per minute (cfm) (0.0203 m3/s) per 1000 Btu/hr
(0.292 kW) input and it is electrically interlocked with the
heater. Makeup air shall be provided to the space to be
heated.