Dade County Building Code (1935)

fire-separation-standards

Properties1
descriptionStructural requirements for segregating occupancies and protecting openings with fire-resistive materials.

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Fire Separation Standards define the structural requirements to segregate different occupancy-classification within a single building, ensuring that fire does not spread between distinct uses. According to the 1935-miami-dade-building-code, specifically in 1935-Miami-Dade-Building-Code_p25_44, these standards are critical for mixed-occupancy buildings where different portions are placed in different occupancy groups (p. 41). The requirements for specific occupancies, such as Group A through E, further detail when “Special” or “Ordinary” separations are mandated for specific rooms like boiler plants (p. 50, 53, 59, 63).

Types of Fire Separation

The code classifies fire separations into three categories based on their fire-resistive duration and construction requirements (p. 42):

  1. Absolute Fire Separation: Provides effective resistance to fire for not less than four hours. No openings are allowed through an Absolute Fire Separation (p. 42).
  2. Special Fire Separation: Provides resistance for not less than three hours. Openings are permitted but must be protected by self-closing, one-hour fire-resistive doors. The total width of openings in any vertical Special Fire Separation cannot exceed 25% of the wall length in that story, and no single opening can exceed 120 square feet (p. 42). This standard is frequently required for boiler rooms burning liquid or solid fuel in Group A, B, C, D, and E buildings (p. 50, 53, 59, 63).
  3. Ordinary Fire Separation: Provides resistance for not less than one hour. Openings must be protected by self-closing metal-clad doors (p. 42). This standard is required for boiler rooms burning gas in Group A, B, C, D, and E buildings (p. 50, 53, 59, 63).

Structural Requirements for Separations

The physical construction of fire-resistive walls and partitions is detailed in Section 4302 of the code fire-resistive-construction-requirements (p. 287). Minimum thicknesses are specified for various materials to achieve the required fire-resistive periods (1 to 4 hours). Acceptable constructions include:

  • Masonry: Solid or hollow brick, concrete, and clay tile walls, with specific requirements for plastering to contribute to fire resistance (p. 288–289).
  • Concrete: Solid concrete or gunite with reinforcement not less than 0.2% in each direction (p. 289).
  • Gypsum and Plaster: Hollow gypsum blocks and solid gypsum or Portland cement plaster on incombustible studding. Plaster must be at least ½ inch thick on each side to be considered part of the fire resistance (p. 287, 289).

Opening Protection

Openings in fire separations must be protected by fire-resistive doors, shutters, and windows that meet specific standards fire-resistive-door-specifications (p. 292).

Fire Doors

One-hour fire-resistive doors are required for Special and Ordinary fire separations. Acceptable types include:

  • Tin-clad wood-core doors: Constructed with three plies of wood and covered with sheet metal, meeting Underwriters’ Laboratories standards (p. 292).
  • Sheet metal doors: Constructed with two sheets of metal with asbestos insulation between them (p. 292).
  • Metal-clad wood panel doors: Wood panels covered with sheet metal (p. 293).

Hardware for these doors must be heavy-duty, using malleable iron or steel, and sliding tracks must be securely supported (p. 293). Fire doors bearing the label of underwriters-laboratories are accepted as meeting these requirements (p. 293).

Fire Windows

One-hour fire-resistive windows must use frames and sash of solid or hollow metal, fabricated without solder. All glass must be wire glass at least ¼ inch thick, with no single light exceeding 720 square inches (p. 294–295). Maximum sizes are limited based on frame type and window operation (p. 295).

Application and Requirements

Fire separations can be vertical, horizontal, or a combination of both. Each segregated portion of a building is considered a separate building for code compliance purposes (p. 42). The specific type of separation required between different occupancy groups (Group A through J) is determined by a matrix provided in the code (p. 44). For example, Major Theatres (Group A, Division 1) require Absolute separation from most other groups, while Ordinary separation may suffice between less hazardous occupancies (p. 44).

Specific Occupancy Applications

  • Group A (Assembly): Boiler rooms or heating plants burning liquid or solid fuel must be separated from the rest of the building with a “Special Fire Separation” (p. 50). Those burning gas require an “Ordinary Fire Separation” (p. 50). Mixed occupancies require separation as specified in Section 503 (p. 50).
  • Group B (Assembly): Similar to Group A, boiler rooms with liquid/solid fuel require Special separation, and gas-fueled plants require Ordinary separation (p. 53). Mixed occupancies must be separated per Section 503 (p. 54).
  • Group C (Assembly/Schools): Boiler room separation rules mirror Groups A and B (p. 59). Mixed occupancies require separation per Section 503 (p. 59).
  • Group D (Detention/Hospital): Boiler room separation rules mirror previous groups (p. 63). Mixed occupancies require separation per Section 503 (p. 63).
  • Group E (High Hazard): Boiler room separation rules mirror previous groups (p. 63).

These standards are part of the broader code-enforcement-mechanisms and are enforced by the building-inspector to ensure life safety and property protection.

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