Which system is held together by vertical posts and horizontal beams, featuring an open stairwell that allows products of combustion to extend from one floor to another?

• A. Balloon Frame
• B. Post and Beam
• C. Type II - Non-Combustible
• D. Type V - Wood Frame Construction

Answer: (B)

The system being described relies on a skeletal framework formed by vertical posts supporting horizontal beams, creating a distinct open, load-bearing frame. This layout leaves large interior voids and often an open stairwell, which becomes a direct vertical conduit for heat, smoke, and flames to move from one floor to the next. That vertical shaft effect is a key fire behavior concern with post-and-beam construction: the fire can extend quickly through the building via these open spaces and the stairwell, rather than being confined by continuous, fire-stopped walls. This is why a post-and-beam framework is the best match for the scenario.