In August 2023, the International Code Council (ICC) announced the release of the first few 2024 International Codes, including the 2024 International Mechanical Code (IMC). This article will review important code changes, the code adoption process, and what ICC calls “the most substantial format changes to the International Codes in 25 years.”
Every three years, ICC introduces potential code changes and starts a governmental consensus process. There are four objectives that ICC follows during every code development cycle. These include:
One of the biggest updates to the 2024 IMC came from a 2021 Environmental Protection Agency (EPA) rule that mandated an 85% phasedown in HFC refrigerants over the next 15 years due to their high global warming potential (GWP).
The final EPA rule now accepts six refrigerant alternatives to HFCs for new residential and light commercial air conditioners and heat pumps. These low-GWP and low-flammable alternatives are classified by the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) as A2L refrigerants.
A2L refrigerants have different flammability characteristics than current A1 refrigerants like R-410A. The 2024 IMC includes several code changes that permit using A2L refrigerants for human comfort uses, consistent with industry standards, and will help to facilitate the phasedown of HFCs following EPA rules.
Other updates approved during the development process include:
When reviewing the code, you may notice the visual and formatting changes that are part of what ICC calls an “ongoing digital transformation.” After collecting feedback from print and digital International Code users, ICC applied substantial formatting changes to improve readability, reduce page count, and offer the same experience to print and digital users.
According to ICC, the formatting updates promote a cleaner, more modern look.
Code change identification has also been overhauled in an effort to help users identify changes more precisely. Now, QR codes replace the marginal sidebar markings and arrows.
Scanning a QR code sends you directly to the digital version of the code change. QR codes are placed at the beginning of any section that has a technical revision. If there is no QR code, there are no technical changes to that section.
For those not interested in using the QR codes, you can manually access the code change online by entering the ID found within the QR code into your browser.
Now that the 2024 IMC is available, it must go through an adoption process. The codes that ICC creates are presented as models or templates that a local authority having jurisdiction (AHJ) — like a state, county, or city — can incorporate into its own laws. Before reviewing, adopting, and incorporating the model code, AHJs usually make changes that reflect local practices and laws.
Due to copyright law, any adopted laws that use the 2024 IMC will incorporate it by reference instead of using any code text. That means an AHJ’s adopted law will cite the title, edition, and publishing information of the 2024 IMC.
It may take some time before HVAC professionals across the country start seeing 2024 IMC changes adopted into their own local laws. Since the new code came out in August 2023, most states are still reviewing it.
Currently, 47 states, the District of Columbia, Guam, Puerto Rico, and the U.S. Virgin Islands have adopted a version of the IMC at the state or local level. But, as you can see in the image below, not all AHJs adopt the newest editions of the IMC right away.
While HVAC professionals wait for their AHJs to adopt a new version of the IMC, we encourage them to review the changes and think about participating in the next code development process. According to ICC, the public comment period for submitting code changes for the 2024–2026 code development cycle started on October 16 and ends on January 8, 2024.
A cdpACCESS account is required to submit code change suggestions, vote on proposed changes, or participate in the public comment period. The first 2024 Committee Action Hearing is currently scheduled for April 7–16, 2024.
As states review and adopt the 2024 IMC, we’ll work on keeping our site updated and make sure all students learn about any updated CE requirements. In the meantime, we encourage all HVAC professionals to use their cdpACCESS account and participate in the next code development cycle!
Campbell, D. (2023, August 31). International Code Council Unveils 2024 International Plumbing Code and 2024 International Mechanical Code. Retrieved from https://www.iccsafe.org/about/periodicals-and-newsroom/international-code-council-unveils-2024-international-plumbing-code-and-2024-international-mechanical-code/
International Code Council. (n.d.). New EPA Refrigerant Rules and their Impact on 2024 I-Codes:
what AHJs, HVAC contractors, and others need to know. Retrieved from https://www.iccsafe.org/events/conference/refrigerant-rules-overview-ac22/
International Code Council. (n.d.). New Design for the 2024 International Codes. Retrieved from https://www.iccsafe.org/about/2024-i-code-updates/
International Code Council. (2022, December 07). CP#28-05 – Code Development. Retrieved from https://www.iccsafe.org/wp-content/uploads/CP-28-05-Code-Development-Procedure-12072022-NEW-FORMAT.pdf
International Code Council. (n.d.). Code Adoption Resources. Retrieved from https://www.iccsafe.org/code-adoption-resources/#faqs
International Code Council. (n.d.). 2024 International Mechanical Code. Retrieved from https://shop.iccsafe.org/international-codes/2024-international-mechanical-coder.html