UNIFORM BUILDING CODE

'1'
Fire Resistive Construction: structural frame of fire-protected structural steel or iron, or of concrete; exterior walls, inner courts, and walls enclosing vertical openings, of fire-resistive construction; roof construction and floors of fire-resistive construction, doors, windows, and other openings in exterior walls protected by Class "E" or "F" fire doors or windows.
'2'
Heavy Timber Construction: structural frame of fire-protected structural steel or iron, of concrete, masonry or heavy timbers, or using bearing walls; exterior walls of fire-resistive construction; inner court walls of incombustible materials or protected solid wood; roof construction of wood or of incombustible materials; floors and non-bearing partitions of wood or incombustible materials; no concealed or inaccessible spaces in combustible framing.
'3'
Ordinary Masonry Construction: interior load-bearing masonry construction, or concrete walls, or structural frame of steel, reinforced concrete or wood; exterior walls of fire-resistive materials; partitions, floors and roof framing of woods.
'4'
Light Incombustible Frame Construction: structural framework of steel, iron, masonry, or concrete; exterior walls of reinforced concrete or wood; exterior walls of fire-resistive materials; partitions, floors and roof framing of woods.
'5'
Wood Frame Construction: enclosed walls, interior walls, partitions, floors, and roofs of wood, or of wood in combination with other materials.

When two or more types of construction occur in the same building and are not separated by an unpierced wall of four-hour fire-resistive construction, the entire building will be classed in the least fire-resistive class of the type to which it most nearly conforms.

Any building which, by its construction, cannot be classified definitely as Type 1, 2, 3, 4, or 5 will be reported as being in the least fire-resistive class of the type to which it most nearly conforms.