No room in any tenement erected or converted since June seventh, one thousand eight hundred and ninety-five, shall be occupied for living purposes, unless it has a window lighting area of at least twelve square feet, the upper half of which surface shall open fully. At least one window of the required size shall open directly upon a street, yard, or open area not less than that provided for in section six of this act. No room in any other building of the grades referred to in this act shall be occupied for living purposes, unless it has a window or windows of an approved lighting area opening to the outer air. The upper half of all such windows shall open fully.
53 P.S. § 14937