
The International Building Code (IBC) either is in use or adopted in all 50 states of the United States of America, as well as the District of Columbia, Guam, Northern Marianas Islands, the U.S. Virgin Islands, and Puerto Rico. However, as it is the International Building Code, and part of a series of International Codes (“I-Codes”), it is used in multiple locations worldwide, including the 15 countries of the Caribbean Community and Common Market (CARICOM), Jamaica, and Georgia. Furthermore, the IBC has served as the basis for legislative building codes in Mexico, Abu Dhabi, and Haiti, among other places.
IBC Development
The International Code Council (ICC) promulgates a new International Building Code every 3 years through the ICC Code Development Process. As such, the current version of the IBC is the 2021 edition, also known as ICC IBC-2021.
Developed through the review of proposed changes submitted by code enforcement officials, industry representatives, design professionals, and other interested parties, the 2021 International Building Code, just as its mass of predecessors, establishes minimum guidelines for building systems that make possible the use of new materials and new building designs. This is carried out in a manner that provides a reasonable level of safety, public health, and general welfare through prescriptive and performance related guidelines.
International Building Code: What’s Covered
In general, the IBC is focused on means of egress facilities, stability, sanitation, adequate light and ventilation, energy conservation, and safety to life and property from fire, explosion, and other hazards. These topics are addressed throughout the 35 chapters of the expansive ICC IBC-2021 document, which each cover a separate topic like Types of Construction (Chapter 6) and Steel (Chapter 22), and Annexes A-N.
While the International Building Code (ICC IBC-2021) serves as the basis for laws and regulations in communities across the United States and in other countries, it is used in a variety of nonregulatory settings, including voluntary compliance programs, the insurance industry, certification of individuals and buildings, U.S. federal agencies, facilities management, best practices benchmarks, and reference works.

International Building Code: Changes to the 2021 Edition
ICC IBC-2021 is a hefty document, containing a plenitude of sections that together comprise over 750 pages. It has undergone numerous changes from the 2018 edition, including but not limited to:
- Puzzle rooms (escape rooms) were defined and regulated as amusement areas (now requiring compliance with Section 411, “Special Amusement Areas”).
- For educational occupancies (Group E), enhanced classroom acoustics in compliance with ICC A117.1 are to be provided in all classrooms with a volume of 20,000 cubic feet or less.
- The use of intermodal shipping containers was specifically addressed.
- Automatic sprinkler protection became required in Group S-2 open parking garages where any fire area exceeds 48,000 square feet.
- ICC A117.1-2017 was adopted (you can learn more about this standard in our post ANSI A117.1-2017: Accessible and Usable Buildings).
- The 2021 IBC snow map was updated to match ASCE 7 snow maps, and secondary rain loads were updated to be consistent with ASCE 7 (you can learn more about this standard in our post ASCE/SEI 7-2022: Minimum Design Loads and Associated Criteria for Buildings and Other Structures).
- Frost protection for egress doors was added to the foundation requirements.
- Three new types of construction (Types IV-A, IV-B, and IV-C) allow mass timber buildings of taller heights, more stories above grade, and greater allowable areas compared to existing provisions for heavy timber buildings.
Any user of International Building Code who wants to see further technical changes made to the 2021 IBC can find them noted through solid vertical lines in the document’s margins.
International Building Code: Changes to the 2018 Edition
The previous edition of the IBC was also a significant revision. Some highlights of the changes made to ICC IBC-2018 from the 2015 edition include:
- Accessory storage spaces of any size became permitted to be classified as part of the occupancy to which they are accessory.
- New code sections were introduced to address medical gas systems and higher education laboratories.
- Use of fire walls to create separate buildings was limited to only the determination of permissible types of construction based on allowable building area and height.
- Where an elevator hoistway door opens into a fire-resistance-rated corridor, the opening should be protected in a manner to address smoke intrusion into the hoistway.
- The occupant load factor for business uses was revised to one occupant per 150 square feet.
- The minimum lateral load that fire walls are required to resist became five pounds per square foot.
- Wind speed maps were updated, including maps for the state of Hawaii.
Other I-Codes by the International Code Council
ICC IBC-2021 does not apply to the repair, alteration, change of occupancy, addition, and relocation of existing buildings, as this is instead the focus of ICC IEBC-2021: 2021 International Existing Building Code. In fact, there are numerous “I-Codes” published by the International Code Council, all of which are fully compatible with one another. These include:
ICC IECC-2021: 2021 International Energy Conservation Code (Learn more in our post 2021 International Energy Conservation Code)
ICC IFC-2021: 2021 International Fire Code (Learn more in our posts 2021 International Fire Code and Commentary to the International Fire Code)
ICC IFGC-2021: 2021 International Fuel Gas Code
ICC IMC-2021: 2021 International Mechanical Code
ICC IPC-2021: 2021 International Plumbing Code
ICC IPMC-2021: 2021 International Property Maintenance Code
ICC IPSDC-2021: 2021 International Private Sewage Disposal Code
ICC IRC-2021: 2021 International Residential Code
ICC ISPSC-2021: 2021 International Swimming Pool And Spa Code (ISPSC)
ICC IWUIC-2021: 2021 International Wildland-Urban Interface Code
ICC IZC-2021: 2021 International Zoning Code
ICC PC-2021: 2021 ICC Performance Code for Buildings and Facilities
ICC IBC-2021: 2021 International Building Code and other ICC standards are available on the ANSI Webstore. Those who need several I-Codes might be interested in the ICC International Building Code Package (IBC).
Thanks for this article.
The International Building Code (IBC) either is in use or adopted in all 50 states of the United States of America.
Montana doesn’t even require permits for single family homes–who in enforcing the IBC/IRC there?
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hi I am working on a project of gas distribution network. RTP gas pipeline will be installed in underground utility corridor having other utilites like HV/LV Cable, telecom,sewer, storm water…issue is there is a very narrow corridor availabe for gas line i.e 1 meter. the gas pressure is 705 psig. i need to know is there any international standard for this type of design.
What states have or are in the process of adopting IBC-21?
we are doing the change in January the later part of. I am relatively new to being a building official and noticed there is not a lot of literature out there that have the significant changes from 15 to 21 i would like to find something i can give to the contractors so when we have a meeting they can look it over and we can decide what amendments we want to change as a whole.