Vertical Opening Enclosure refers to the structural and fire-resistive requirements for sealing vertical shafts, stairways, ramps, and elevator hoists to prevent the rapid spread of fire and smoke between floors. The 1935 Miami Dade Building Code p225 244 mandates that these enclosures be constructed based on the building’s occupancy and type, ensuring continuity from the lowest to the highest required point (p. 238).
Stairway and Ramp Enclosures
Stairways and ramps must be enclosed in walls or partitions of not less than two-hour fire-resistive construction, as specified in Section 4302 (p. 238). Exceptions exist for specific occupancies (Groups H and I) where one-hour construction may be permitted (p. 238).
- Doors: Must be self-closing and of at least one-hour fire-resistive construction (p. 238). In buildings under three stories of Types II–V, solid wood slab doors (1⅜” thick) are permitted, but not in smokeproof-towers (p. 238).
- Windows: Must be wire glass with metal frames and sash, unless facing a street/court and not within 10 feet of a lot line (p. 238).
- Ramps: Require solid wall enclosures from floor to floor, with no openings other than self-closing, one-hour fire-resistive doors (p. 238).
Elevator Enclosures
Elevator shafts must be enclosed in masonry conforming to partition requirements for the building type (p. 239).
- Openings: Limited to two per story, not wider than the platform and not exceeding 7’6” in height (p. 239).
- Protection: Openings must be protected by walls and doors of at least one-hour fire-resistive construction (p. 239).
- Capacity: No more than two elevators are allowed in one enclosure; banks of two elevators must be separated by one-hour fire-resistive walls (p. 239).
Other Vertical Openings
Shafts, ducts, and chutes not covered by stair/elevator rules must have enclosing walls conforming to the building’s type of construction (p. 239).
- Lining: Inner vertical surfaces must be completely covered with incombustible materials (p. 239).
- Clearances: Combustible partitions must be kept at least 3 inches from the lining or protected with ⅜” plaster or ¼” asbestos/plaster board (p. 239).
- Sealing: Openings between ducts and floor construction must be filled with mortar or incombustible material supported by wire baskets to prevent fire passage (p. 239).
- Doors/Windows: Doors into shafts must be metal; windows must be wire glass with metal frames or wood clad with 26-gauge metal (p. 239).
These requirements are integral to fire-separation-standards and egress-and-exit-standards, ensuring safe evacuation paths and limiting fire propagation.
Related Documents
See also: 1935-Miami-Dade-Building-Code_p245_264