The provisions of this regulation shall govern the minimum standards for basic equipment and facilities used for light and ventilation of a structure.
In place of the means for natural light and ventilation prescribed in this code, alternative arrangement of windows, louvers, or other devices or methods that will provide the equipment minimum performance requirements shall be permitted.
A. 
All areas in a structure shall be provided sufficient light so as not to endanger health and safety. All areas in a structure shall be provided with natural light or equipment to accommodate artificial light of sufficient intensity and distribution so as to permit the maintenance of sanitary conditions and the safe use of the area and the appliances, equipment and fixtures.
B. 
Common halls and stairways. Each common hall and stairway in a structure, other than one- and two-family structures, shall be adequately lighted at all times with an illumination equivalent to at least a sixty-watt standard incandescent light bulb for each 200 square feet of floor area, provided that the spacing between lights may not be greater than 30 feet. Every exterior stairway and exit shall be illuminated.
A. 
All areas in a structure shall be provided sufficient ventilation so as not to endanger health and safety.
B. 
Mechanical ventilation.
(1) 
When mechanical ventilation is provided instead of natural ventilation, the mechanical ventilating system shall be maintained in operation during the occupancy of the structure or portion of it.
(2) 
When part of the air provided by a mechanical ventilation system is recirculated, the portion or volume of air recirculated may not be recirculated to a different habitable area.