# Stack Vent: Building Code Definition

> How the IRC 2009, IPC 2009 define stack vent, where the wording differs, and which chapters depend on the term.

- Canonical: https://harth.build/resources/glossary/stack-vent/
- Last updated: 2026-09-07
- Data source: 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.

## Key facts

| Fact | Value |
| --- | --- |
| Defined in | IRC 2009, IPC 2009 (2009 editions transcribed in this corpus) |
| Primary source | IRC 2009 Definitions (model text, not a jurisdiction's adopted text) |
| Chapters using the term | 6 (counted across the codes hosted here) |
| Wording identical across codes | No (compare before citing one code's wording under another) |

## Direct answer

Stack vent is a defined term in the International Residential Code (IRC) 2009, in Definitions. The code's own words are: “The extension of soil or waste stack above the highest horizontal drain connected.” The IPC 2009 words it differently, in Definitions: “The extension of a soil or waste stack above the highest horizontal drain connected to the stack.” The IPC 2009 defines the same term with different wording, so the controlling text depends on which code governs the question in front of you — the comparison below sets the versions side by side. The term is used in 6 chapters of this corpus, most often in Vents (IPC 2009), Vents (IRC 2009), Definitions (IPC 2009). These pages transcribe the 2009 model text; verify the definition against the edition and amendments your authority having jurisdiction has adopted.

*Content and cited inputs reviewed by [Scott Barrington](https://nz.linkedin.com/in/barrington), Harth founder and architectural technology specialist · Published 2026-09-07 · Updated 2026-09-07.*

## What does this term mean?

**Stack Vent** — IRC 2009, Definitions:

> The extension of soil or waste stack above the highest horizontal drain connected.

![Labeled code-term definition diagram: Stack Vent: Building Code Definition](https://efwwel0vyt9vy5so.public.blob.vercel-storage.com/images/glossary/stack-vent/diagram-1344.webp)

*How the IRC 2009, IPC 2009 define stack vent, where the wording differs, and which chapters depend on the term.*

## What must be verified before using this guidance?

Two of the I-Codes in this corpus define **Stack Vent**, and the wording is not identical — read the version that governs your question.

| Code | Where it is defined | Definition |
| --- | --- | --- |
| IRC 2009 | [Definitions](https://harth.build/resources/building-codes/us-states/maryland/irc-2009/definitions.md) | The extension of soil or waste stack above the highest horizontal drain connected. |
| IPC 2009 | [Definitions](https://harth.build/resources/building-codes/us-states/new-hampshire/ipc-2009/definitions.md) | The extension of a soil or waste stack above the highest horizontal drain connected to the stack. |

## Where stack vent is used in the code

The term appears in 6 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](https://harth.build/resources/building-codes/us-states/new-hampshire/ipc-2009/vents.md) | IPC 2009 | 23 |
| [Vents](https://harth.build/resources/building-codes/us-states/maryland/irc-2009/vents.md) | IRC 2009 | 18 |
| [Definitions](https://harth.build/resources/building-codes/us-states/new-hampshire/ipc-2009/definitions.md) | IPC 2009 | 3 |
| [Definitions](https://harth.build/resources/building-codes/us-states/maryland/irc-2009/definitions.md) | IRC 2009 | 3 |
| [Sanitary Drainage](https://harth.build/resources/building-codes/us-states/maryland/irc-2009/sanitary-drainage.md) | IRC 2009 | 2 |
| [Sanitary Drainage](https://harth.build/resources/building-codes/us-states/new-hampshire/ipc-2009/sanitary-drainage.md) | IPC 2009 | 1 |

### The term in use

How the code actually writes about stack vent, quoted from the 2009 text hosted here:

> All individual, branch and circuit vents shall connect to a vent stack, stack vent, air admittance valve or extend to the open air.

— [IPC 2009 §905.1](https://harth.build/resources/building-codes/us-states/new-hampshire/ipc-2009/vents.md)

> All individual branch and circuit vents shall connect to a vent stack, stack vent or extend to the open air.

— [IRC 2009 §3104.1](https://harth.build/resources/building-codes/us-states/maryland/irc-2009/vents.md)


## The terms stack vent is built out of

The definition above leans on 3 other defined terms. Each carries its own code definition, and a local amendment to any of them changes what stack vent covers:

- **[Waste](https://harth.build/resources/glossary/waste.md)** — IRC 2009: Liquid-borne waste that is free of fecal matter.
- **[Drain](https://harth.build/resources/glossary/drain.md)** — IRC 2009: Any pipe that carries soil and water-borne wastes in a building drainage system.
- **[Stack](https://harth.build/resources/glossary/stack.md)** — IRC 2009: Any main vertical DWV line, including offsets, that extends one or more stories as directly as possible to its vent terminal.

## Stack Vent: what to open, and in what order

Every row is a document this term depends on. The [ICC code library](https://codes.iccsafe.org/codes) and the [ICC adoption maps](https://www.iccsafe.org/advocacy/code-adoption-maps/) cover the middle rows.

| Check | Where | Confirmed |
| --- | --- | --- |
| Read the definition in the adopted IRC | Definitions | |
| 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 | Vents (IRC 2009) | |
| Re-check the requirement that uses it | Definitions (IPC 2009) | |
| Re-check the requirement that uses it | Definitions (IRC 2009) | |
| Confirm the dependent definition | Waste | |
| 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?

- [Explore all glossary guidance](https://harth.build/resources/glossary.md)
- [Waste: Building Code Definition](https://harth.build/resources/glossary/waste.md)
- [Stack: Building Code Definition](https://harth.build/resources/glossary/stack.md)
- [Drain: Building Code Definition](https://harth.build/resources/glossary/drain.md)

## 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](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.

### Source links

- [codes.iccsafe.org](https://codes.iccsafe.org/codes)

- [iccsafe.org](https://www.iccsafe.org/advocacy/code-adoption-maps/)

## Frequently asked questions

### What is the code definition of stack vent?

The International Residential Code (IRC) 2009 defines it in Definitions as: “The extension of soil or waste stack above the highest horizontal drain connected.” 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 stack vent?

In this corpus the term is used across 6 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 the definition of a vent stack?

Vent Stack is a separate defined term. The IRC 2009 defines it as: “A vertical vent pipe installed to provide circulation of air to and from the drainage system and which extends through one or more stories.” That is not the same as stack vent, which the IRC 2009 defines as “The extension of soil or waste stack above the highest horizontal drain connected.” — read both before applying either, and confirm the wording in the edition your jurisdiction has adopted.

### What are the code requirements for plumbing stack vents?

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 stack vent, which the IRC 2009 defines as “The extension of soil or waste stack above the highest horizontal drain connected.” — read both before applying either, and confirm the wording in the edition your jurisdiction has adopted.

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