In order to encourage greater flexibility in design, more attractive arrangements of buildings and greater utilization of open spaces, yard regulations for multifamily dwellings are hereby established for single development and for locating several buildings within a group development.
   The yards of multifamily buildings shall be attractively landscaped and related to the space within the dwelling units as well as the yards. Buildings shall be arranged so as to assure privacy between adjacent buildings and intersecting wings of buildings, and from streets and parking and recreation areas, in accordance with the following:
   (a)   Terms used in this section are defined as follows:
      (1)   Cluster development: A development which utilizes the design technique which concentrates buildings in specific areas on the site, allowing the remaining land to be used for recreation, common open space and the preservation of natural areas and environmentally sensitive features. This type of development shall not be governed by the formulas and restrictions listed in subsections (b) through (j) hereof. Yard regulations for cluster developments are listed in Section 1270.32.
      (2)   End or secondary wall: Any exterior wall of a multifamily building, other than a main wall, containing secondary windows of a dining or sleeping room, principal or minor windows of a kitchen or bathroom, or no windows.
      (3)   Group development: A development of more than one multifamily building on a parcel planned as a unit and coordinated with the surrounding neighborhood.
      (4)   Main wall: Any exterior wall of a multifamily building containing the principal windows of a living, dining and/or sleeping room or rooms.
      (5)   Overlapping walls: That portion of the exterior walls which are directly opposite, when two buildings that are parallel, or within thirty degrees of being parallel, face each other across an open yard or court.
      (6)   Single development: A development of one multifamily building on one lot coordinated with the surrounding neighborhood and fronting on a dedicated street.
   (b)   The distance between facing and overlapping buildings or parts thereof in a group development of multifamily buildings shall vary in direct relation to the length and height of buildings. Such minimum distance shall be determined by the formula,
            Minimum Distance =   LA + LB + HA + HB
      The elements of the formula are shown in Illustration E, as follows: