Fire Wall Construction refers to the specific structural and material requirements for walls designed to prevent the spread of fire between buildings or distinct sections of a building. According to the 1935-miami-dade-building-code, these walls must be continuous from the foundation to at least 18 inches above the roof level (p. 234).
Solid Masonry Fire Walls
Solid masonry fire walls must be no less than 12 inches thick, while reinforced concrete fire walls must be at least 8 inches thick (p. 234). For hazardous-occupancy-requirements (Groups H and I), solid masonry fire walls may be 8 inches thick for the uppermost 25 feet but must be 12 inches thick for the lower portion (p. 234). These walls cannot be broken into for structural members after construction, and a 4-inch solid masonry separation is required between combustible members entering from opposite sides (p. 234).
Hollow Masonry Fire Walls
Hollow masonry fire walls are prohibited in fire-zones No. 1 (p. 235). Generally, they must be at least 16 inches thick, though 12 inches is permitted for Groups H and I (p. 235). Combustible or unprotected steel members framing into hollow fire walls (≤12 inches thick) cannot project more than 4 inches and must be spaced to maintain a 4-inch separation, with surrounding spaces filled with fire-resistive materials (p. 235).
Fire Division Walls
fire-separation-standards also include fire division walls, which must have a fire-resistive rating of at least four hours and meet thickness requirements for exterior bearing walls of corresponding height (p. 235).
Parapet Walls
fire-wall-construction often extends into parapet walls. On most buildings, exterior and fire walls must project as parapets 18 inches above the roof, unless the building is low-rise (≤20 feet) or fronts a street with an incombustible roof (p. 235). Parapets exceeding six times their thickness in height require lateral support (p. 235).
See also vertical-opening-enclosure and 1935-Miami-Dade-Building-Code_p225_244.