Building Code Glossary
Adapter Fitting: Building Code Definition
How the IPC 2009 define adapter fitting, where the wording differs, and which chapters depend on the term.
On this page
Last updated September 7, 2026 · Definitions quoted from the 2009 International Codes as transcribed in this site's building-codes collection, with the source chapter linked for each quotation. Usage counts are computed over the chapters hosted here, one copy per code. The [ICC code library](https://codes.iccsafe.org/codes) publishes the current model text and the [ICC adoption maps](https://www.iccsafe.org/advocacy/code-adoption-maps/) show which edition a jurisdiction has adopted; those sources control.
Direct answer
Adapter fitting is a defined term in the International Plumbing Code (IPC) 2009, in Definitions. The code's own words are: “An approved connecting device that suitably and properly joins or adjusts pipes and fittings which do not otherwise fit together.” No other I-Code in this corpus defines it, so the IPC 2009 definition is the one to work from. The term is used in 9 chapters of this corpus, most often in Sanitary Drainage (IPC 2009), Sanitary Drainage (IRC 2009), Water Supply and Distribution (IRC 2009). These pages transcribe the 2009 model text; verify the definition against the edition and amendments your authority having jurisdiction has adopted. Record the jurisdiction, the adopted edition, the application date and any local amendment that rewrites the definition before you use it on a live project, because a term redefined by amendment changes every requirement that depends on it.
Content and cited inputs reviewed by Scott Barrington, Harth founder and architectural technology specialist · Published 2026-09-07 · Updated 2026-09-07.
What does this term mean?
Adapter Fitting — IPC 2009, Definitions:
An approved connecting device that suitably and properly joins or adjusts pipes and fittings which do not otherwise fit together.
What must be verified before using this guidance?
Adapter Fitting is defined once in this corpus, in the Definitions chapter of the International Plumbing Code (IPC) 2009:
An approved connecting device that suitably and properly joins or adjusts pipes and fittings which do not otherwise fit together.
Where adapter fitting is used in the code
The term appears in 9 chapters of the 2009 I-Codes hosted here. The chapters that lean on it hardest are the ones to read next.
| Chapter | Code | Mentions |
|---|---|---|
| Sanitary Drainage | IPC 2009 | 6 |
| Sanitary Drainage | IRC 2009 | 6 |
| Water Supply and Distribution | IRC 2009 | 6 |
| Fuel Oil Piping and Storage | IMC 2009 | 2 |
| Hydronic Piping | IMC 2009 | 2 |
| Materials | IPC 2009 | 2 |
| Water Supply and Distribution | IPC 2009 | 2 |
| Fuel Gas | IRC 2009 | 2 |
| Definitions | IPC 2009 | 1 |
The term in use
How the code actually writes about adapter fitting, quoted from the 2009 text hosted here:
Joints between cast-iron and galvanized steel or brass pipe shall be made by either caulked or threadedjoints or with an approved adapter fitting.
Joints between cast-iron and galvanized steel or brass pipe shall be made by either caulked or threaded joints or with an approved adapter fitting.
Joints between different types of plastic pipe or between plastic pipe and other piping material shall be made with an approved adapter fitting.
The terms adapter fitting is built out of
The definition above leans on 2 other defined terms. Each carries its own code definition, and a local amendment to any of them changes what adapter fitting covers:
- Approved — IBC 2009: Acceptable to the code official or authority having jurisdiction.
- Device — IRC 2009: Aunit of an electrical system that carries or controls electrical energy as it principal function.
Adapter Fitting: what to open, and in what order
Every row is a document this term depends on. The ICC code library and the ICC adoption maps cover the middle rows.
| Check | Where | Confirmed |
|---|---|---|
| Read the definition in the adopted IPC | Definitions | |
| Re-check the requirement that uses it | Sanitary Drainage (IPC 2009) | |
| Re-check the requirement that uses it | Sanitary Drainage (IRC 2009) | |
| Re-check the requirement that uses it | Water Supply and Distribution (IRC 2009) | |
| Re-check the requirement that uses it | Fuel Oil Piping and Storage (IMC 2009) | |
| Confirm the dependent definition | Approved | |
| Confirm the dependent definition | Device | |
| Local amendment to any of the above | Jurisdiction's amendment list |
A research aid, not a code determination. The authority having jurisdiction decides which edition and which amendments apply.
Where can you explore related guidance?
Sources and method
Definitions quoted from the 2009 International Codes as transcribed in this site's building-codes collection, with the source chapter linked for each quotation. Usage counts are computed over the chapters hosted here, one copy per code. The ICC code library publishes the current model text and the ICC adoption maps show which edition a jurisdiction has adopted; those sources control.
Source links
Frequently asked questions
What is the code definition of adapter fitting?
The International Plumbing Code (IPC) 2009 defines it in Definitions as: “An approved connecting device that suitably and properly joins or adjusts pipes and fittings which do not otherwise fit together.” The 2009 model text is reproduced here; the definition that binds your project is the one in the edition your jurisdiction has adopted, as amended locally.
Which parts of the code depend on adapter fitting?
In this corpus the term is used across 9 chapters, led by Sanitary Drainage in the IPC 2009. Those are the sections whose scope moves if the definition is amended locally, so read them together with Chapter 2 rather than on their own.
What are the plumbing code requirements for fixtures?
Plumbing is a separate defined term. The IRC 2009 defines it as: “For the purpose of this code, plumbing refers to those installations, repairs, maintenance and alterations regulated by Chapters 25 through 33.” That is not the same as adapter fitting, which the IPC 2009 defines as “An approved connecting device that suitably and properly joins or adjusts pipes and fittings which do not otherwise fit together.” — read both before applying either, and confirm the wording in the edition your jurisdiction has adopted.
What is an adapter fitting?
In the 2009 I-Codes hosted here it is a defined term rather than a description. The IPC 2009 states, in Definitions: “An approved connecting device that suitably and properly joins or adjusts pipes and fittings which do not otherwise fit together.” It is defined in IPC 2009. Because it is a defined term, whatever the adopted edition says it means is what every section using it means — so check Chapter 2 of that edition and any local amendment before relying on this wording.
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