Type 3 street walls, as shown on Map 4 in Appendix A of this Chapter, shall comply with the provisions of this Section.

(a)        The upper street wall shall be located within two feet of the 12th Avenue mandatory widened sidewalk line, and shall extend along no more than 70 percent of the length of the mandatory widened sidewalk line of the Parcel. Any upper street wall located on the remaining portion of the street frontage of the Parcel shall be set back from the 12th Avenue widened sidewalk line by a minimum distance of either:

(1)        20 feet, if such setback area faces both 12th Avenue and a narrow street; or

(2)        10 feet, if such setback area faces only 12th Avenue.

(b)        The lower street wall shall be located at the same distance from the mandatory widened sidewalk line, or set back not more than 10 feet from the upper street wall required pursuant to paragraph (a) of this Section, and shall extend along at least 80 percent of the length of such required upper street wall. No street wall location regulations shall apply to the remaining portion of the lower street wall frontage of a Parcel.

(c)        The street wall provisions of this Section may apply along a narrow street within 100 feet of its intersection of a wide street.