Section 602 of the International Building Code lists the various building categories. All structures must be categorised into one of the five categories of construction described in Sections 602.2 through 602.5.

To be classified for a certain construction type, the building elements must meet the fire-resistance requirements listed in Tables 601 and 602.

What is Type I Construction, and what does it entail?

Type I construction uses fireproof materials for the building elements mentioned in Table 601 unless otherwise specified in Section 603.

Concrete, masonry, and non-combustible steel are examples of such materials.

The phrase “non-combustible material” refers to a substance that passes the ASTM E 136 test protocols for determining the combustibility of primary materials.

While non-combustible materials are required for all construction elements in a Type I structure, Section 603 specifies when combustible materials may be utilised.

Section 603 lists 26 things that direct you to other parts of the code that permit you to utilise the materials specified in this section.

While they are flammable materials, they are modest compared to the entire structure. Millwork used as door frames or window sashes, for example, is one of the materials specified. Despite being flammable, they are permitted in noncombustible structures due to code restrictions.

Any substance not designated as noncombustible is referred to as “combustible material.”

What is Type II Construction, and how does it differ from Type I?

Type II construction is the same as Type I construction, except that the non-combustible building materials mentioned in Table 601 are used unless otherwise specified in Section 603.

What is Type III Construction, and what does it entail?

The external walls of Type III construction are made of fireproof materials, while the inner building parts can be made of any material authorised by regulation. This means that the internal structure can be either combustible or noncombustible materials.