Chimneys (other than chimneys for central heating plants), flues, ventilators, skylights, towers, bulkheads, water tanks, cooling towers, and all other decorative features and necessary mechanical appurtenances and similar features usually carried above the roof level, but excluding telegraph, radio and television transmission or broadcasting antennas, and flagpoles shall be exempt from the height provisions of this chapter, provided that:
[1] The aggregate area covered by all such features shall not exceed 15% of the area of the roof of the building of which they are a part.
[2] The height of each such feature shall not exceed five feet above the level of such roof.
[3] All such features shall be constructed or enclosed within walls of a material and design deemed by the Planning Board to be in harmony with that of the mail walls of the building of which they are a part.
[4] Purely architectural embellishments for purposes of providing light, such as atrium roofs or skylights, shall also be permitted, provided that the same do not exceed a height of five feet above the finished roof, and provided that the same do not occupy, in addition to the other appurtenances heretofore allowed by this section, more than 20% of the roof area.
[5] The exterior treatment of all such mechanical penthouses and other projections also permitted herein shall be of materials substantially similar to the facade of the building itself and shall be similarly designed so as to be architecturally an integral part of the structure. The determination of compliance with all aspects of this section shall be by the approving authority as a function of site plan approval.