Excavations near a public street. Any person, firm, association or corporation owning land within the corporate limits of the Village of Stewart Manor, upon which land there is any public street, sidewalk, road or highway as a result of which the surface shall be lower than the grade of the public street, sidewalk, road or highway adjacent to said land, shall construct a chain link fence along the boundaries of such land adjacent to said public street, sidewalk, road or highway. Such chain link fence shall be constructed so as to prevent children and other persons from gaining access to said premises in which the excavation is located. Such chain link fence shall be a minimum height of seven feet in the business zone and four feet in all residential zones. The height requirements set forth in this section may be varied only in the discretion of the Building Inspector upon good cause shown.