The following regulations shall control the computation and measurement of sign area, sign height, window area and building frontage:
(a) Determining Sign Area or Dimension.
(i) Sign area shall include the face of all the display area of the sign. Sign area shall not include the frame and structural support unless such structural support is determined to constitute an integral part of the sign design.
(ii) For a sign that is framed, outlined, painted or otherwise prepared and intended to provide a background for a sign display, the area of the sign shall be the area of one rectangular shape that encompasses the entire background or frame.
(iii) For a sign comprised of individual letters, figures, or elements on a wall or similar surface of a building or structure, or an irregular shaped ground sign, the area of the sign shall be the area of one rectangular shape that encompasses the perimeter of all the elements in the display.
(1) When separate elements are organized to form a single sign, but the elements are separated by open space, the area shall be the area of one rectangular shape that comprises all the display areas, including the space between the elements.
(2) One minor extension may be permitted to extend above or below the sign area when the area of the extension is less than 25 percent of the open space included in the sign area. For the purposes of this Chapter, only the open space within the sign area that is located above and below the majority of the letters shall be included in the calculation.
(3) For ground signs and projecting signs, the sign area shall be computed by the measurement of one of the faces when two identical display faces are joined, are parallel or within 30 degrees of being parallel to each other.
(4) Air under a ground sign between supporting posts, air between a projecting sign and the wall to which it is attached, and lighting fixtures and associated brackets shall not be included in the calculation of sign area.
(b) Determining Sign Height. The height of a sign shall be measured from the average grade at the base of the sign or support structure to the tallest element of the calculated sign area or support structure. A ground sign on a man-made base, including a graded earth mound, shall be measured from the average site grade prior to the addition of the sign.
(c) Determining Building Frontage and Building Unit. For the purposes of these sign regulations, the length of the building wall that faces a public street or that contains a public entrance to the uses therein shall be considered the building frontage.
(i) The building frontage shall be measured along such building wall between the exterior faces of the exterior side walls.
(ii) In the case of an irregular wall surface, a single straight line extended along such wall surface shall be used to measure the length.
(iii) A building shall have only one building frontage except as otherwise set forth below.
(iv) A building shall have two frontages whenever the lot fronts on two or more streets, or the building has a public entrance on a wall other than the wall that faces the street. The property owner shall determine which wall shall be the primary building frontage and which wall shall be the secondary building frontage. Only one outside wall of any business shall be considered its primary frontage and only one additional wall considered its secondary frontage.
(v) For multi-occupant buildings, the portion of a building that is owned or leased by a single occupant shall be considered a building unit. The building frontage for a building unit shall be measured from the centerline of the party walls defining the building unit.
(d) Determining Window Area. The window area of a building shall be the total glass area of windows on the building frontage. For the purposes of determining window area for ground floor occupants, the ground floor shall be considered to be no more than 15 feet in height above grade.