Building Code Glossary
Fixture Branch: Building Code Definition
How the IPC 2009 define fixture branch, 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
Fixture branch is a defined term in the International Plumbing Code (IPC) 2009, in Definitions. The code's own words are: “A drain serving two or more fixtures that discharges to another drain or to a stack.” 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 4 chapters of this corpus, most often in Vents (IPC 2009), Definitions (IRC 2009), Vents (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?
Fixture Branch — IPC 2009, Definitions:
A drain serving two or more fixtures that discharges to another drain or to a stack.
What must be verified before using this guidance?
Fixture Branch is defined once in this corpus, in the Definitions chapter of the International Plumbing Code (IPC) 2009:
A drain serving two or more fixtures that discharges to another drain or to a stack.
Where fixture branch is used in the code
The term appears in 4 chapters of the 2009 I-Codes hosted here. The chapters that lean on it hardest are the ones to read next.
| Chapter | Code | Mentions |
|---|---|---|
| Vents | IPC 2009 | 6 |
| Definitions | IRC 2009 | 5 |
| Vents | IRC 2009 | 4 |
| Definitions | IPC 2009 | 2 |
The term in use
How the code actually writes about fixture branch, quoted from the 2009 text hosted here:
The relief vent is permitted to be a fixture drain or fixture branch for fixtures located within the same branch interval as the circuit-vented horizontal branch.
The fixture branch or fixture drain shall connect to the combination waste and vent within a distance specified in Table P31 05.1.
The terms fixture branch 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 fixture branch covers:
- Drain — IRC 2009: Any pipe that carries soil and water-borne wastes in a building drainage system.
- Stack — IRC 2009: Any main vertical DWV line, including offsets, that extends one or more stories as directly as possible to its vent terminal.
Fixture Branch: 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 | Vents (IPC 2009) | |
| Re-check the requirement that uses it | Definitions (IRC 2009) | |
| Re-check the requirement that uses it | Vents (IRC 2009) | |
| Re-check the requirement that uses it | Definitions (IPC 2009) | |
| Confirm the dependent definition | Drain | |
| Confirm the dependent definition | Stack | |
| 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 fixture branch?
The International Plumbing Code (IPC) 2009 defines it in Definitions as: “A drain serving two or more fixtures that discharges to another drain or to a stack.” 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 fixture branch?
In this corpus the term is used across 4 chapters, led by Vents 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 is not considered a plumbing fixture?
Plumbing Fixture is a separate defined term. The IRC 2009 defines it as: “A receptor or device that requires both a water-supply connection and a discharge to the drainage system, such as water closets, lavatories, bathtubs and sinks. Plumbing appliances as a special class of fixture are further defined.” That is not the same as fixture branch, which the IPC 2009 defines as “A drain serving two or more fixtures that discharges to another drain or to a stack.” — read both before applying either, and confirm the wording in the edition your jurisdiction has adopted.
What does fixture mean in plumbing?
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 fixture branch, which the IPC 2009 defines as “A drain serving two or more fixtures that discharges to another drain or to a stack.” — read both before applying either, and confirm the wording in the edition your jurisdiction has adopted.
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