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Indiana mechanical, plumbing, fuel gas & energy codes

The Indiana Fire Prevention and Building Safety Commission adopts all building, fire and energy codes statewide (675 IAC). Indiana's mechanical, plumbing, fuel gas and commercial energy codes are among the oldest still in force in the US.

Quick answer: Indiana currently uses the 2012 IMC for mechanical work and the 2006 IPC for plumbing (see sources and dates below). A2L status: Variance needed: no statewide A2L rule found

Adopted codes

Mechanical
2012
IMC
Adopted as
2014 Indiana Mechanical Code (675 IAC 18-1.6)
Effective
2014-12-01
Source
Indiana DHS – Rules of the FPBSC
Last checked
2026-10-27 verified
Notes
Being readopted without changes before the Jan 1, 2027 rule-expiration date (LSA #25-779).
Plumbing
2006
IPC
Adopted as
2012 Indiana Plumbing Code (675 IAC 16-1.4)
Effective
2012-12-24
Source
Indiana DHS – Rules of the FPBSC
Last checked
2026-10-27 verified
Fuel Gas
2012
IFGC
Adopted as
2014 Indiana Fuel Gas Code (675 IAC 25-3)
Effective
2014-12-01
Source
Indiana DHS – Rules of the FPBSC
Last checked
2026-10-27 verified
Notes
Included in the LSA #25-779 readoption.
Energy
Commercial: ASHRAE 90.1-2007; Residential: 2018 IECC (DOE)
ASHRAE 90.1 / IECC (via IRC)
Adopted as
2010 Indiana Energy Conservation Code (675 IAC 19-4); 2020 Indiana Residential Code
Effective
Com 2010-05-06; Res 2019-12-26
Source
Indiana DHS – Rules of the FPBSC; U.S. DOE BECP – Indiana
Last checked
2026-10-27 verified
Notes
Residential energy rules are in the 2020 Indiana Residential Code (2018 IRC base). DOE: https://www.energycodes.gov/status/states/indiana

A2L refrigerants in Indiana

The 2012 IMC base doesn't list newer A2L refrigerants such as R-454B in Table 1103.1. No statewide A2L amendment was found on the DHS rules page. Indiana DHS variance records show projects getting A2L variances conditioned on ASHRAE 15-2022. Whether a statewide fix exists or is planned has not been confirmed. Rechecked Oct 29, 2026: the DHS rules page still lists the 2014 Indiana Mechanical Code (2012 IMC) and no A2L rule.

Source: https://www.in.gov/dhs/boards-and-commissions/fpbsc-rules/ · Last checked 2026-10-29 unverified

How A2L rules work nationally

Local amendments & things to watch

  • Rule readoption (LSA #25-779): the 2014 Indiana Building, Mechanical, Fire and Fuel Gas Codes are being readopted before they expire Jan 1, 2027. The comment deadline was Oct 16, 2026. verified source
  • Indiana's Building Code Update Committee is drafting a rule to update the Indiana Building Code (675 IAC 13-2.6) to the 2024 IBC. Its posted meetings run through Dec 2024. Timing for mechanical and other codes is not verified. unverified source