Ohio mechanical, plumbing, fuel gas & energy codes
The Ohio Board of Building Standards (BBS) adopts statewide commercial codes in OAC Title 4101. The 2024 Ohio Building, Mechanical and Plumbing Codes, based on the 2021 I-Codes, took effect March 1, 2024. Certified local departments enforce them.
Quick answer: Ohio currently uses the 2021 IMC for mechanical work and the 2021 IPC for plumbing (see sources and dates below). A2L status: Allowed: 2024 IMC Chapter 11 adopted (effective Oct 15, 2025)
Adopted codes
Mechanical
2021
IMC
- Adopted as
- 2024 Ohio Mechanical Code (OAC 4101:2)
- Effective
- 2024-03-01
- Source
- Ohio Dept. of Commerce – 2024 OBC/OMC/OPC Rules
- Last checked
- 2026-10-27 verified
- Notes
- Amended effective 2025-10-15 (Amendments Group 105) to bring in the 2024 IMC Chapter 11 refrigeration provisions.
Plumbing
2021
IPC
- Adopted as
- 2024 Ohio Plumbing Code (OAC 4101:3)
- Effective
- 2024-03-01
- Source
- Ohio Dept. of Commerce – 2024 Ohio Plumbing Code Rules
- Last checked
- 2026-10-27 verified
Fuel Gas
2021
IFGC
- Adopted as
- International Fuel Gas Code (referenced by OBC 101.4.1)
- Effective
- 2024-03-01
- Source
- Ohio BBS – 2024 Ohio Building, Mechanical & Plumbing Code Rules
- Last checked
- 2026-10-29 verified
- Notes
- OBC 101.4.1 applies the IFGC to gas piping and appliances. Ohio BBS lists the 2021 IFGC as a referenced standard for the 2024 Ohio codes, which took effect Mar 1, 2024. Ohio's Chapter 35 changes (OAC 4101:1-35-01, eff. Oct 15, 2025) leave the IFGC-21 entry unchanged.
Energy
Residential: 2018 IECC; Commercial: 2021 IECC & ASHRAE 90.1-2019
IECC / ASHRAE 90.1
- Adopted as
- OBC Ch. 13 (commercial); Residential Code of Ohio Ch. 11
- Effective
- Res 2019-07-01; Com 2024-03-01
- Source
- U.S. DOE Building Energy Codes Program – Ohio
- Last checked
- 2026-10-27 verified
A2L refrigerants in Ohio
BBS Amendments Group 105 amended OAC 4101:2-11-01, effective Oct 15, 2025. It brings in the 2024 IMC Chapter 11 refrigeration provisions, including the A2L concentration limits in Table 1103.1, and revises the 1109.2.5 piping exception.
Source: https://dam.assets.ohio.gov/image/upload/com.ohio.gov/DICO/BBS/Rule%20Docs/dico_bbs_omc_amendments_october_2025.pdf · Last checked 2026-10-27 verified
Local amendments & things to watch
- The 2024 OAC rules list only Ohio's deletions and changes. The full combined text is in the Ohio code books on ICC's free Ohio eCode bookshelf. verified source