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D.C. Municipal Regulations (Last Updated: September 13, 2017) |
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Title 14. HOUSING |
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Chapter 14-5. HOUSING CODE: HEATING, LIGHTING, AND VENTILATION |
Section 14-502. LIGHTING IN HABITABLE ROOMS
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502.1Each habitable room shall have a glass area transmitting natural light equivalent to that which would be transmitted by a clear glass area at least equal to one tenth (1/10) of the floor area served, consisting of one or more of the following:
(a)Windows;
(b)Glazed doors;
(c)Glazed doors with either or both side lights or transoms; or
(d)Other glass construction facing directly to the outside.
502.2Rooms opening on enclosed porches and meeting the lighting requirements of Article 501-01-e of the 1941 Building Code, as amended (Title 12, DCMR) and rooms lighted through sunporches and meeting the lighting requirements of § 3-515 of the 1961 Building Code, as amended, shall be deemed to have adequate natural light.
502.3The sash area of openable windows, side lights, or transoms, the horizontal projection of the glass area of skylights, and in all other instances the gross glass area, shall be used in computing the required glass area.
502.4Any portion of any glass area facing directly on any wall, portion of a structure, or other light obstruction less than three feet (3 ft.) from that glass area, shall not be included as contributing to the required natural light.
502.5At least fifty percent (50%) of the required glass area shall be a window, glazed door, side light, or transom, each glazed with clear glass.
502.6Obscure glass, glass blocks, or other approved translucent material may be used to transmit up to fifty percent (50%) of the required natural light.