All permanent swimming pools constructed, installed, established, or maintained will be completely and continuously surrounded by a permanent durable wall, fence, or barrier, which will be no more than six feet nor less than four feet in height above grade, and will have no opening, mesh, hole, or gap larger than two inches in any dimension, except for doors and gates; provided, however, that if a picket fence is erected or maintained, the horizontal dimension of any gap or opening will not exceed 2 1/2 inches. All fences will be constructed in accordance with other Borough ordinances regulating fences. No fence may contain projections of any kind at any point on the fence's outer surface. A dwelling house or accessory building may be used as part of the required enclosure. All gates used in conjunction with any of the above-described enclosures will conform to the specifications required above as to height and dimensions of openings, mesh, holes, or gaps in the case of fences, and all gates and doors will be equipped with self-closing and self-latching devices to keep the gate or door securely closed at all times when the pools is not in use. Gates and doors must be locked when the pool is not in use or is unguarded or unattended; provided, however, that nothing herein contained will be construed to require the construction of an additional wall, fence, or barrier where, in lieu thereof, the entire premises or a part thereof wherein the pool is contained will be fully enclosed by a wall, fence, or barrier that meets the specifications set forth herein.