The 2021 International Building Code (IBC) applies to all buildings and structures except detached one- and two-family dwellings and townhouses that are within the scope of the International Residential Code (IRC). This edition introduces numerous updates aimed at improving safety, accessibility, structural performance, and code clarity.

Among the significant revisions, puzzle rooms, commonly known as escape rooms, are now specifically defined and regulated as special amusement areas, requiring compliance with Section 411 and enhanced means-of-egress provisions. For determining the allowable number of hazardous material control areas, portions of a building separated by one or more fire walls are now considered separate buildings.

Accessibility and occupant comfort have also been enhanced. In Group E educational occupancies, classrooms with a volume of 20,000 cubic feet or less must provide improved acoustical performance in accordance with ICC A117.1 standards. The 2017 edition of ICC A117.1 has been adopted, updating accessibility requirements throughout the code.

The provisions governing metal composite materials (MCM) on exterior walls of Types I, II, III, and IV construction have been simplified, and previous sprinkler-related allowances have been removed. In addition, the code now includes specific requirements for the use of intermodal shipping containers as buildings, providing guidance that supplements existing IBC provisions.