A tilt slab building is classified as which NFPA 220 construction type?

• A. Type III
• B. Type IV
• C. Type II
• D. Type V

Answer: (C)

NFPA 220 construction types are based on the combustibility of the structural elements and the level of fire resistance of assemblies. A tilt slab building uses poured concrete panels for the exterior and typically a concrete or noncombustible interior structure, with no wood framing involved. Concrete and steel reinforcement are noncombustible, so the building falls under noncombustible construction. That category is designated as Type II.

For contrast, Type I is fire-resistive with higher-rated assemblies, Type III has noncombustible exterior walls but wood interior framing, Type IV uses heavy timber, and Type V uses wood framing throughout. So a standard tilt slab fits best as Type II.