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The Indiana Department of Health (IDOH) posted its formal adoption notice on September 2, 2026, confirming that the 2026 FGI Guidelines will govern any Indiana healthcare project application submitted on or after June 1, 2027. This replaces the 2018 FGI Guidelines, which have been Indiana's mandatory standard for new construction since January 1, 2020. The 2026 edition splits enforceable code from supplemental guidance, adds a dedicated commissioning chapter, and fully incorporates ANSI/ASHRAE/ASHE Standard 170-2025, the ventilation standard that sets air change rates, filtration levels, and pressure relationships in Indiana hospitals, surgical centers, and outpatient facilities.
What Did IDOH Announce?
IDOH's authority to set this timeline comes directly from statute. Under Indiana Code 16-21-2-12.5, enacted through House Enrolled Act 1457 in the 2025 legislative session, IDOH must post notice of a new FGI edition within 90 days of its publication (IC 16-21-2-12.5(c)(1)), then set an enforcement date between 270 and 360 days after that notice (IC 16-21-2-12.5(c)(2)).
FGI published the 2026 edition on August 31, 2026. IDOH posted its adoption notice on the Health Care Engineering webpage two days later, on September 2, 2026, satisfying the 90-day requirement, and set June 1, 2027, as the enforcement date, 272 days after the notice, within the statutory 270-to-360-day window. The Indiana Society for Healthcare Engineering has separately confirmed this same timeline and noted that IDOH is moving directly from the 2018 edition to the 2026 edition, skipping the 2022 edition entirely, since the 2026 Guidelines were published before the new statutory process would have allowed 2022 to take effect.
The effective date governs the project application, not the construction schedule. Any application submitted before June 1, 2027, is reviewed under the 2018 FGI Guidelines currently in force. Any application submitted on or after June 1, 2027, is reviewed under the 2026 FGI Codes.
What Changed From the 2018 FGI Guidelines?
FGI restructured its publication model for the 2026 edition. The single "Guidelines" document that mixed enforceable minimums with explanatory commentary is now split into two products: the FGI Codes, written in mandatory, enforceable language and intended for adoption by regulators like IDOH, and separate FGI Handbooks that carry design rationale, illustrations, and non-mandatory guidance.
Part 1 of the 2026 Codes is reorganized into five sequential chapters that follow a project's lifecycle: Introduction, Planning, Design, Construction, and Commissioning. Commissioning now has its own dedicated chapter, separated from general construction requirements. This structural change puts functional verification, confirming that ventilation, pressure relationships, and mechanical sequences perform as designed, on equal footing with design and construction as a distinct, named phase of the code.
What Does ASHRAE 170-2025 Change for Ventilation?
The 2026 FGI Codes for Planning and Design incorporate ANSI/ASHRAE/ASHE Standard 170-2025 in full, including all issued addenda. Indiana's current mandatory standard, the 2018 FGI Guidelines, references ANSI/ASHRAE/ASHE Standard 170-2017. The jump from the 2017 to the 2025 edition of Standard 170 spans eight years of addenda and revisions. As HFM Magazine reported, Standard 170-2025 includes these changes:
- Updated imaging space requirements. Class 2 and Class 3 imaging rooms and their associated non-imaging spaces have revised ventilation requirements, with clarified guidance for nuclear medicine spaces.
- Expanded unoccupied turndown guidance for outpatient spaces, extending turndown provisions across more space types. Aero covered a related turndown mandate under ASHRAE 90.1's Addendum bh, which governs operating room and imaging room turndown under a separate energy standard.
- Updated cooling and heating reserve capacity and fuel on-site requirements, affecting how central plant systems get sized and specified for healthcare occupancies.
- Revised stack discharge requirements, including separation distances and discharge heights for more complex site configurations.
- New allowances for natural ventilation in specific applications, where the 2017 edition addressed only mechanical ventilation.
- Reorganized construction-phase ventilation requirements under Section 10, governing how infection control risk assessments interact with ventilation during active construction near occupied spaces.
What Changed: 2018 FGI / ASHRAE 170-2017 vs. 2026 FGI / ASHRAE 170-2025
| Area | 2018 FGI / ASHRAE 170-2017 (Indiana's current standard) | 2026 FGI / ASHRAE 170-2025 (effective June 1, 2027) |
|---|---|---|
| Document structure | Single Guidelines document mixing mandatory and advisory content | Split into enforceable Codes and separate advisory Handbooks |
| Part 1 organization | Construction and commissioning requirements distributed across general chapters | Reorganized into five lifecycle chapters, including a dedicated Commissioning chapter |
| Imaging space ventilation | 2017-edition requirements for Class 2/3 imaging rooms | Updated requirements for imaging rooms and associated non-imaging spaces, with clarified nuclear medicine guidance |
| Unoccupied turndown | Limited to specific space types | Expanded guidance, particularly for outpatient spaces |
| Central plant capacity | 2017-edition reserve capacity requirements | Updated cooling/heating reserve capacity and fuel on-site requirements |
| Construction-phase ventilation | Addressed within general construction sections | Reorganized under a dedicated Section 10 |
Which Indiana Projects Does the June 1, 2027 Date Affect?
The IDOH Health Care Engineering program states directly that the 2026 FGI Codes apply to any project application submitted on or after midnight EST on June 1, 2027. A hospital renovation or new construction project that submits its application before that date is reviewed under the 2018 FGI Guidelines currently in force, regardless of how long construction takes afterward. A project that submits on or after June 1, 2027, is reviewed under the 2026 edition, which means its mechanical design, ventilation systems, and commissioning plan need to be built around ASHRAE 170-2025 and the reorganized Part 1 requirements from the start, not retrofitted onto a design based on the outgoing standard.
Frequently Asked Questions
When does the 2026 FGI Guidelines requirement take effect in Indiana?
Enforcement begins June 1, 2027, at 12:00 a.m. EST, per IDOH's September 2, 2026 adoption notice. It applies to any healthcare project application submitted on or after that date, not to the date construction starts or finishes.
What edition governs Indiana healthcare projects right now?
The 2018 FGI Guidelines, mandatory for new construction plans submitted on or after January 1, 2020, remain Indiana's enforced standard until June 1, 2027. Indiana is skipping the 2022 FGI edition entirely and moving directly from 2018 to 2026, since the 2026 Guidelines published before the new statutory notice process would have allowed the 2022 edition to take effect.
Does this affect projects already in design or under construction?
Projects that submit their application before June 1, 2027, continue under the 2018 FGI Guidelines regardless of how long construction takes. Only applications submitted on or after the effective date fall under the 2026 requirements, so a project's application date, not its construction schedule, determines which edition governs.
What is the practical difference between the old "Guidelines" and the new "Codes"?
The 2026 edition separates mandatory, enforceable requirements (the FGI Codes) from supplemental design guidance, rationale, and illustrations (the new FGI Handbooks). Previously, both lived in one document. Authorities like IDOH adopt and enforce the Codes; the Handbooks remain a reference resource rather than an enforceable document.
Does the 2026 FGI Guidelines change ventilation requirements for Indiana hospitals?
Yes. The 2026 Codes incorporate ANSI/ASHRAE/ASHE Standard 170-2025 in full, replacing the 170-2017 edition referenced by Indiana's current 2018 FGI Guidelines. Changes include updated requirements for imaging spaces, expanded unoccupied turndown guidance, revised central plant reserve capacity requirements, and reorganized construction-phase ventilation provisions. These are the technical requirements that TAB and commissioning verify against once a project is designed and built.
Why does FGI 2026 add a dedicated commissioning chapter?
Part 1 of the 2026 Codes follows a project's lifecycle across five chapters, with commissioning named as its own chapter rather than folded into general construction requirements. This structural change reflects how central functional verification, confirming that ventilation, pressure relationships, and mechanical sequences perform as designed, is to getting a healthcare facility from substantial completion to a code-compliant, operational building.
Where to Start
Indiana healthcare projects submitting after June 1, 2027, need ventilation, pressure relationship, and air change verification built around ASHRAE 170-2025 from the start, which is the compliance testing work Aero's compliance services cover for critical environment pressurization and air change verification. If a project is heading toward design under the 2026 FGI Codes, or an existing Indiana healthcare facility needs its ventilation systems tested against the current standard, start that conversation now, before an application is submitted under the wrong code edition. Request an ASHRAE 170 compliance assessment.
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