# Fireplace Throat: Building Code Definition

> How the IBC 2009, IRC 2009 define fireplace throat, where the wording differs, and which chapters depend on the term.

- Canonical: https://harth.build/resources/glossary/fireplace-throat/
- 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 | IBC 2009, IRC 2009 (2009 editions transcribed in this corpus) |
| Primary source | IBC 2009 Masonry (model text, not a jurisdiction's adopted text) |
| Chapters using the term | 4 (counted across the codes hosted here) |
| Wording identical across codes | Yes (compare before citing one code's wording under another) |

## Direct answer

Fireplace throat is a defined term in the International Building Code (IBC) 2009, in Masonry. The code's own words are: “The opening between the top of the firebox and the smoke chamber.” The IRC 2009 carries the same definition word for word, so the term means the same thing in each. The term is used in 4 chapters of this corpus, most often in Masonry (IBC 2009), Chimneys and Fireplaces (IRC 2009), Definitions (IBC 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](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?

**Fireplace Throat** — IBC 2009, Masonry:

> The opening between the top of the firebox and the smoke chamber.

![Labeled code-term definition diagram: Fireplace Throat: Building Code Definition](https://efwwel0vyt9vy5so.public.blob.vercel-storage.com/images/glossary/fireplace-throat/diagram-1344.webp)

*How the IBC 2009, IRC 2009 define fireplace throat, 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 **Fireplace Throat**, in identical words.

| Code | Where it is defined | Definition |
| --- | --- | --- |
| IBC 2009 | [Masonry](https://harth.build/resources/building-codes/us-states/maryland/ibc-2009/masonry.md) | The opening between the top of the firebox and the smoke chamber. |
| IRC 2009 | [Definitions](https://harth.build/resources/building-codes/us-states/maryland/irc-2009/definitions.md) | The opening between the top of the firebox and the smoke chamber. |

## Where fireplace throat 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 |
| --- | --- | --- |
| [Masonry](https://harth.build/resources/building-codes/us-states/maryland/ibc-2009/masonry.md) | IBC 2009 | 4 |
| [Chimneys and Fireplaces](https://harth.build/resources/building-codes/us-states/maryland/irc-2009/chimneys-and-fireplaces.md) | IRC 2009 | 3 |
| [Definitions](https://harth.build/resources/building-codes/us-states/maryland/ibc-2009/definitions.md) | IBC 2009 | 1 |
| [Definitions](https://harth.build/resources/building-codes/us-states/maryland/irc-2009/definitions.md) | IRC 2009 | 1 |

### The term in use

How the code actually writes about fireplace throat, quoted from the 2009 text hosted here:

> The fireplace throat or damper shall be located a minimum of 8 inches (203 mm) above the top of the fireplace opening.

— [IBC 2009 §2111.7](https://harth.build/resources/building-codes/us-states/maryland/ibc-2009/masonry.md)

> The fireplace throat or damper shall be located a minimum of 8 inches (203 mm) above the lintel.

— [IRC 2009, Chimneys and Fireplaces](https://harth.build/resources/building-codes/us-states/maryland/irc-2009/chimneys-and-fireplaces.md)

## Fireplace Throat: 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 IBC | Masonry | |
| Read the definition in the adopted IRC | Definitions | |
| Re-check the requirement that uses it | Masonry (IBC 2009) | |
| Re-check the requirement that uses it | Chimneys and Fireplaces (IRC 2009) | |
| Re-check the requirement that uses it | Definitions (IBC 2009) | |
| Re-check the requirement that uses it | Definitions (IRC 2009) | |
| 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)
- [Chimney: Building Code Definition](https://harth.build/resources/glossary/chimney.md)
- [Tile: Building Code Definition](https://harth.build/resources/glossary/tile.md)
- [Fireplace: Building Code Definition](https://harth.build/resources/glossary/fireplace.md)
- [Masonry: Building Code Definition](https://harth.build/resources/glossary/masonry.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 fireplace throat?

The International Building Code (IBC) 2009 defines it in Masonry as: “The opening between the top of the firebox and the smoke chamber.” 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 fireplace throat?

In this corpus the term is used across 4 chapters, led by Masonry in the IBC 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 building code requirements for fireplace surrounds?

Building is a separate defined term. The IBC 2009 defines it as: “Any structure used or intended for supporting or sheltering any use or occupancy.” That is not the same as fireplace throat, which the IBC 2009 defines as “The opening between the top of the firebox and the smoke chamber.” — read both before applying either, and confirm the wording in the edition your jurisdiction has adopted.

### Is a chimney liner required by code?

Chimney is a separate defined term. The IBC 2009 defines it as: “A primarily vertical enclosure containing one or more passageways for conveying flue gases to the outside atmosphere.” That is not the same as fireplace throat, which the IBC 2009 defines as “The opening between the top of the firebox and the smoke chamber.” — read both before applying either, and confirm the wording in the edition your jurisdiction has adopted.

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