Steel loses roughly half its yield strength by 600 degrees Celsius. Concrete spalls. Timber chars. Left unprotected, a building's structural skeleton can fail well before occupants finish evacuating or firefighters arrive. That gap between fire onset and structural collapse is exactly what fire protection of structural elements closes.

The IBC assigns every construction type a set of hourly fire resistance ratings through Table 601. Type I-A demands 3-hour protection on the primary structural frame; Type II-B demands none. The method you choose to hit those ratings varies by material, geometry, cost, and aesthetics. Spray-applied fire-resistive materials (SFRM) coat steel cheaply but look rough. Intumescent coatings sit thin until heat triggers them to swell into an insulating char. Concrete encasement buries steel inside a protective shell. Gypsum board wraps members in a non-combustible box. Membrane protection, like a rated ceiling assembly, shields everything above it.

For the PDD exam, you need to understand how each method works, when each is appropriate, and how the IBC connects construction type to the required fire resistance rating. You also need to apply these concepts at the detail level, choosing protection strategies and verifying that documented assemblies meet code. The architect's role is to ensure that the selected fire protection system is compatible with the structural design, fits within the architectural enclosure dimensions, and is properly documented.