In what had become a rare occurrence, but showing signs of a willingness to once again adopt changes to stay ahead of the curve, the Ohio Board of Building Standards has adopted new rules that modify the suite of Ohio Building Codes. The effective date for these changes is October 15, 2025.

Most of the adopted changes are editorial in nature, with the exception of two noteworthy changes that are worth highlighting.

1. A2L Refrigerants

A significant change which will bring relief to multi-family building design amongst others, adopts language that has already been approved to be adopted as part of the 2027 International Mechanical Code and already made, and refined in the 2022 and 2024 ASHRAE Standards that govern the implementation of A2L refrigerants. The change makes minor tweaks to the language of the IMC, but has a significant impact as the majority of scenarios where A2L refrigerants are run will no longer be required to be located within shafts. A mechanical engineer should be consulted to provide guidance and the ASHRAE standard has some clarifications that mechanical engineers should follow. Building Officials should also take note of the subtle changes in the ASHRAE standard in evaluating enforcement.

2. Regulation of Modular Rooms

The code change introduces a definition and includes requirements for “modular rooms,” which are typically used as pre-fabricated phone booths or small meeting rooms that gained popularity during the pandemic for their flexibility and ease of relocation. While attractive to owners (and often treated as equipment for tax purposes), these rooms raised safety and accessibility concerns. Inspectors frequently observed them obstructing exit paths and lacking sprinklers or fire alarm integration.

The Board of Building standards adopted code language which does 3 things:

1. 1. Requires that building permits be obtained when using these modular rooms.
   2. Establishes rules for how and if they are to be tied into building life safety systems and
   3. By incorporating them as part of the building code and not providing exceptions requires that they be used with accessibility in mind.

Building Officials and Plans Examiners should take note that the definition has been thoughtfully written to exclude modular wall systems, by stating these rooms include a ceiling.

Why This Matters

Both of these changes are welcome additions to the Ohio Building Code. Up until the last decade, Ohio has often been a leader in the adoption and writing of practical changes to the model building code. It will be interesting to see if these most recent adoptions continues a recent trend to recapture that progressive leadership to find real-world solutions facing the built environment that had become muted by the Ohio Legislature.

At MA Design, we view these changes not simply as technical updates, but as indicators of where the industry is headed. For our clients, they represent opportunities to reduce unnecessary costs in projects using A2L refrigerants, to deploy modular rooms more safely and inclusively and to trust that Ohio is shaping codes with the future in mind.