The following remarks were made regarding the article “2021 ICC Mechanical Code is a mess,” written by Julius Ballanco, P.E., CPD, F-ASPE, president of J.B. Engineering and Code Consulting, published in the July 2020 issue of PM Engineer:

No rock left unturned and no corner skipped in the development of IMC 

In the July edition of PM Engineer magazine, an article was authored by Julius Ballanco, P.E., CPD, noting what he believes to be an “error” in the most recent edition of the International Mechanical Code (IMC). To alleviate any potential confusion, the goal of this letter to the editor is to provide additional insight into the topic for a more comprehensive view into the development of IMC.

Updated on a three-year cycle, all are welcome to participate with the code development process, and usually do. After all, the I-Codes are developed in an open forum with a balance of interests represented and due process that, ultimately, ensures a consensus outcome. This includes, but is not limited to, federal agencies, building and fire code officials, architects, engineers, contractors, consultants and home builders. Even homeowners have participated, in several instances, to speak on code issues that have impacted their lives. While in the case of the IMC, a vast array of mechanical industry experts such as engineers, manufacturers, trade associations and installation contractors participate. This all-encompassing transparent public process ensures the final consensus result balances safety, affordability, resiliency and other public interest considerations.

When adopted, model codes will affect a variety of stakeholders. Understanding this, the International Codes (I-Codes) need to be reflective of industry needs as a whole (in this case mechanical) and not favor a single position or point-of-view.

However, it is acknowledged that some may be confused about alterations to referenced standard requirements, where similar text is located within the codes themselves. In the few instances where the I-Codes extract text from other standards and insert them into the body of the code, the text becomes subject to the actions of the International Code Council’s (ICC) code development process and subsequently may be amended through the code change process, which is exactly what occurred in this case.

This is a great example of why certain administrative section(s) are located within Chapter 1 of the IMC. Chapter 1 states referenced standards are, in fact, part of the code, but only to the prescribed extent of the specific reference. Chapter 1 further explains that in the event of any conflict between the referenced standards and the requirements of the code, the provisions of the code shall apply. These provisions are put in place to address the many circumstances including the specific circumstances outlined in the subject article. The reality is, in some instances, the local AHJ may need to evaluate the use of certain products as they filter into the marketplace. This concept is not new, but rather commonly practiced. As you can imagine, many technologies across the construction industry are constantly evolving and may not have found their way into the codes yet. The ICC code development process is designed to provide an opportunity for new technologies, innovative methods, products and ideas to be vetted in a timely manner, as occurred in this instance.

With the above in mind, it is easy to understand the Code Correlation Committee’s position on non-intervention, as this was not a “correlation issue” or a “known mistake,” but rather a result of the code development process, and the text in the 2021 IMC is written exactly as the voting membership intended.

However, the author asks, should this one item impact a state’s or locality’s decision to adopt the 2021 IMC? To briefly recap, during the 2021 IMC code change process, more than 125 proposed changes were originally submitted. More than half of those proposals, in some form, were successfully incorporated into the contents of the 2021 IMC. The 2021 IMC is a more up-to-date document, with technology and overall mechanical substance, than the previous edition. So, to accurately answer the question, a resounding yes is the correct reply. A state or locality should adopt the 2021 IMC as soon as possible, and begin taking full advantage of the newly updated provisions that occurred throughout the document.

After all, these are codes and standards created by the community for the community. With that in mind, we encourage and invite anyone and everyone to participate in the ICC code development process.

Guy Tomberlin
vice president of PMG programs and resources,
International Code Council

PM Engineer wants to hear your thoughts. If you have any comments concerning our articles or other topics related to the PHVAC industry, send them to for possible inclusion in the Letters to the Editor section of the magazine.