Fire and smoke protection features and interior finishes
Domain 3 covers fire and smoke protection features, interior finishes, and the fire protection systems that support them. The exam focuses on rated assemblies, opening protectives, and finish classifications.
Rated construction
Chapter 7 establishes fire walls, fire barriers, fire partitions, smoke barriers, and horizontal assemblies. Each has a required fire-resistance rating and limits on openings. Opening protectives must match the assembly: a 1-hour fire barrier generally requires a 3/4-hour fire door assembly, installed and maintained per NFPA 80. Penetrations and joints need listed protection systems.
Interior finishes
Chapter 8 classifies interior wall and ceiling finishes by flame spread: Class A is 0-25, Class B is 26-75, and Class C is 76-200. Table 803.13 limits the class by occupancy, sprinkler status, and location, such as exit access corridors. Smoke-developed index is also limited. Floor finishes are Class I or II under Chapter 8.
Fire protection systems
Chapter 9 requires automatic sprinklers, standpipes, fire alarm, and smoke control based on occupancy, height, area, and special hazards. The inspector verifies approved shop drawings, hydraulic calculations, and final acceptance tests.
Worked example
A 1-hour fire barrier separates a storage room from an office corridor. The plans show a standard wood door. That is a violation: the opening must be a 3/4-hour fire door assembly with a self-closing device, labeled frame, and proper clearance. The inspector checks the label, the closing action, and the penetration protection above the ceiling.
Traps
Confusing a fire partition with a fire barrier; specifying flame spread but ignoring smoke-developed index; accepting a door label without checking the frame and hardware; forgetting that sprinklered buildings may allow lower finish classes but not unlimited use.