602.2 Types of Construction

Type I & II are the most common construction for commercial and industrial use

Code Excerpt:

602.2 Types I and II.
Types I and II construction are those types of construction in which the building elements listed in Table 601 are of noncombustible materials.

602.3 Type III.
Type III construction is that type of construction in which the exterior walls are of noncombustible materials and the interior building elements are of any material permitted by this code. Fire-retardant-treated wood framing complying with Section 2303.2 shall be permitted within exterior wall assemblies of a 2-hour rating or less.

602.4 Type IV.
Type IV construction (Heavy Timber, HT) is that type of construction in which the exterior walls are of non-combustible materials and the interior building elements are of solid or laminated wood without concealed spaces. The details of Type IV construction shall comply with the provisions of this section. Fire-retardant-treated wood framing complying with Section 2303.2 shall be permitted within exterior wall assemblies with a 2-hour rating or less.