(a) General.
(1) Scope. The provisions of this regulation shall govern the minimum standards for basic equipment and facilities used for light and ventilation of a structure.
(2) Alternative methods and devices. In place of the means for natural light and ventilation prescribed in this regulation, alternative arrangement of windows, louvers or other devices or methods that will provide the equivalent minimum performance requirements shall be permitted in order to comply with the City of Frederick building code.
(b) Light.
(1) General. 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 distributed so as to permit the maintenance of sanitary conditions and the safe use of the area and the appliances, equipment and fixtures.
(2) 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 the foot candles provided by at least sixty (60) watt standard incandescent light bulb for two hundred (200) square feet of floor area, provided that the spacing between lights may not be greater than thirty (30) feet. Every exterior stairway shall be illuminated.
(c) Ventilation.
(1) General. All areas in a structure shall be provided sufficient ventilation so as not to endanger health and safety.
(2) Mechanical ventilation.
a. 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.
b. When part of the air provided by a mechanical ventilations system is recirculated, the portion or volume of air recirculated may not be recirculated to a different habitable area. (Ord. No. G-88-21, § .11, 12-8-88)

Cross reference--Lighting and ventilation of toilets and bathrooms, § 12-28.