Updated 2026-09-07

Building Code Glossary

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.

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.

Add to Harth agentView as markdown

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, 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 — 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	The opening between the top of the firebox and the smoke chamber.
IRC 2009	Definitions	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	IBC 2009	4
Chimneys and Fireplaces	IRC 2009	3
Definitions	IBC 2009	1
Definitions	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

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

— IRC 2009, Chimneys and Fireplaces

Fireplace Throat: 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 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.

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 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.

Related pages

The AI-powered workspacefor architects.

Get started for free Continue in Harth