Type II construction is a classification in the International Building Code (IBC) for buildings whose structural elements, walls and floors are made of noncombustible materials, such as steel or concrete, but with lower fire-resistance ratings than Type I.
It has two subtypes. Type IIA requires a 1-hour fire-resistance rating for the primary structural frame and floors. Type IIB is noncombustible but generally requires no fire-resistance rating for those elements. The construction type, together with occupancy and sprinklers, sets how tall and how large a building may be under IBC Chapter 5 and, for parking garages, Section 406. See Type I construction.
In parking structures
- Many freestanding open parking garages are built as Type IIB or Type IIA, using unprotected or lightly protected concrete or steel, because the IBC allows open garages generous heights and areas for their construction type.
- Precast and cast-in-place concrete often provide inherent fire resistance, so a concrete garage may meet a higher type without added fireproofing.
- Garages attached to or beneath other occupancies may need a higher construction type or rated separations. See fire wall.
The Parkonomics view
Construction type is one of the first code decisions on a garage and one of the most expensive to change later. Confirm the type, the open or enclosed classification and the allowable height and area together, before the structural system is chosen.
Related terms: Type I Construction, International Building Code, Group S-2, Open Parking Garage, 1-Hour Fire Resistance