Fire Behavior and Building Classifications

Basic building classifications: crucial in determining how a structure behaves during a fire.
Occupancy classification affects the fire risk and safety measures required.
Fire or fuel load refers to the amount and nature of combustible materials in a building.
Fire resistance indicates how well a building can withstand fire exposure.

Structures are initially classified based on the materials used in their construction.
Building classifications indicate the likelihood of structural collapse during fire and the safety of occupants.
Numerical designation is the only means used by building codes to indicate a building's classification.

Type I: Fire resistive, featuring noncombustible components, with fire resistance ratings of 2-4 hours for bearing walls and 1-2 hours for roof decks.
Type II: Noncombustible or protected noncombustible, where Type II-A requires components to have 1-hour fire resistance and Type II-B can have unprotected components.
Type III: Exterior protected, often with masonry or equivalent materials; has Type III-A (protected) and Type III-B (unprotected) subclasses.
Type IV: Heavy timber construction, with solid or laminated wood structural elements and no concealed spaces. Designation 2HH indicates heavy timber dimensions.
Type V: Wood frame construction, allowing for combustible materials in structural components, often requiring a fire resistance rating.

Establishes types of building construction with classifications represented by a 3-digit number that indicates fire resistance ratings for walls, frames, and floors.

Commonly uses protected steel frames or reinforced concrete components, with insulation for steel to enhance fire resistance.
Local codes apply to interior partitions and occupancies.

Type II-A allows for protected noncombustible components with 1-hour fire ratings.
Type II-B consists of unprotected noncombustible components, commonly resulting in faster failure during fires depending on factors like ceiling height and steel member size.

Combines masonry with ordinary framing, using concealed spaces that must have fire stops to prevent fire spread.
Common features include 2x10" joists and potential combustible concealed spaces post-renovation.

Type IV is recognized for its heavier structural wood components and lack of concealed spaces, posing unique fire hazards due to fuel present in supports.
Type V allows all structural components to be combustible with extensive voids, alongside specific height and area limitations imposed by building codes.