Which construction type is generally considered to have the lowest fire resistance for structural elements?

• A. Type V (Wood Frame)
• B. Type I (Fire-Resistive)
• C. Type II (Noncombustible)
• D. Type III (Ordinary)

Answer: (A)

The main idea here is how the materials and assemblies behind a building’s structure determine how well it stands up in a fire. Wood-frame construction uses timber members that are combustible, so the structural elements themselves have relatively low inherent fire resistance. This means they lose strength and integrity more quickly when exposed to fire. In contrast, fire-resistive or protected assemblies (Type I) rely on protected, noncombustible materials like concrete and steel with fireproof coatings, and Type II uses noncombustible materials throughout, both of which provide higher fire resistance. Type III mixes a masonry exterior with wood or metal framing but still benefits from the masonry and protective details that boost fire resistance compared with plain wood framing. Because of these differences, wood-frame construction is generally considered to have the lowest fire resistance for structural elements. Fire resistance can be improved with protective finishes or enclosures, but the inherent baseline is lowest for wood-frame construction.