All districts
Fence rules live in Chapter 19 of the City Code, not the zoning ordinance. Every fence or privacy screen needs a permit from the Building Department before construction (19-3, 19-4).
On interior lots, a fence, including a fully sight-obscuring one, may run along side and rear lot lines and along the front yard setback line at 3 to 6 feet above grade; fences may not extend into the front yard (19-8.A). On corner lots, a sight-obscuring fence may project up to 10 feet into the street-side front yard, and a non-sight-obscuring fence of 3 to 4 feet may stand in that street-side yard, with special limits where corner rear yards meet an interior side yard (19-8.B).
Barbed wire, spikes, and pointed toppers are prohibited, as are electrified fences (19-9, 19-10). Nothing over 30 inches may stand in the 25 foot corner sight triangle (Section 28.03 of the zoning ordinance). Privacy screens up to 6 feet are allowed in rear yards at least 3 feet off the lot line (19-7). Fence variances go to the Board of Ordinance Appeals, not the Zoning Board of Appeals (19-11).