# Fire Wall: Building Code Definition

> How the IBC 2009, IFC 2009 define fire wall, where the wording differs, and which chapters depend on the term.

- Canonical: https://harth.build/resources/glossary/fire-wall/
- 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, IFC 2009 (2009 editions transcribed in this corpus) |
| Primary source | IBC 2009 Fire and Smoke Protection Features (model text, not a jurisdiction's adopted text) |
| Chapters using the term | 19 (counted across the codes hosted here) |
| Wording identical across codes | No (compare before citing one code's wording under another) |

## Direct answer

Fire wall is a defined term in the International Building Code (IBC) 2009, in Fire and Smoke Protection Features. The code's own words are: “A fire-resistance-rated wall having protected openings, which restricts the spread of fire and extends continuously from the foundation to or through the roof, with sufficient structural stability under fire conditions to allow collapse of construction on either side without collapse of the wall.” The IFC 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 19 chapters of this corpus, most often in Fire and Smoke Protection Features (IBC 2009), Special Detailed Requirements Based on Use and Occupancy (IBC 2009), Duct Systems (IMC 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?

**Fire Wall** — IBC 2009, Fire and Smoke Protection Features:

> A fire-resistance-rated wall having protected openings, which restricts the spread of fire and extends continuously from the foundation to or through the roof, with sufficient structural stability under fire conditions to allow collapse of construction on either side without collapse of the wall.

![Labeled code-term definition diagram: Fire Wall: Building Code Definition](https://efwwel0vyt9vy5so.public.blob.vercel-storage.com/images/glossary/fire-wall/diagram-1344.webp)

*How the IBC 2009, IFC 2009 define fire wall, 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 **Fire Wall**, and the wording is not identical — read the version that governs your question.

| Code | Where it is defined | Definition |
| --- | --- | --- |
| IBC 2009 | [Fire and Smoke Protection Features](https://harth.build/resources/building-codes/us-states/maryland/ibc-2009/fire-and-smoke-protection-features.md) | A fire-resistance-rated wall having protected openings, which restricts the spread of fire and extends continuously from the foundation to or through the roof, with sufficient structural stability under fire conditions to allow collapse of construction on either side without collapse of the wall. |
| IFC 2009 | [Definitions](https://harth.build/resources/building-codes/us-states/rhode-island/ifc-2009/definitions.md) | A fire-resistance-rated wall having protected openings, which restricts the spread of fire and extends continuously from the foundation to or through the roof, with sufficient structural stability under fire conditions to allow collapse of construction on either side without collapse ofthe wall. |

## Where fire wall is used in the code

The term appears in 19 chapters of the 2009 I-Codes hosted here. The chapters that lean on it hardest are the ones to read next.

| Chapter | Code | Mentions |
| --- | --- | --- |
| [Fire and Smoke Protection Features](https://harth.build/resources/building-codes/us-states/maryland/ibc-2009/fire-and-smoke-protection-features.md) | IBC 2009 | 111 |
| [Special Detailed Requirements Based on Use and Occupancy](https://harth.build/resources/building-codes/us-states/maryland/ibc-2009/special-detailed-requirements-based-on-use-and-occupancy.md) | IBC 2009 | 9 |
| [Duct Systems](https://harth.build/resources/building-codes/us-states/new-hampshire/imc-2009/duct-systems.md) | IMC 2009 | 7 |
| [Fire Protection Systems](https://harth.build/resources/building-codes/us-states/rhode-island/ifc-2009/fire-protection-systems.md) | IFC 2009 | 6 |
| [Fire Protection Systems](https://harth.build/resources/building-codes/us-states/maryland/ibc-2009/fire-protection-systems.md) | IBC 2009 | 5 |
| [General Building Heights and Areas](https://harth.build/resources/building-codes/us-states/maryland/ibc-2009/general-building-heights-and-areas.md) | IBC 2009 | 5 |
| [Fire-resistance-rated Construction](https://harth.build/resources/building-codes/us-states/rhode-island/ifc-2009/fire-resistance-rated-construction.md) | IFC 2009 | 4 |
| [Exhaust Systems](https://harth.build/resources/building-codes/us-states/new-hampshire/imc-2009/exhaust-systems.md) | IMC 2009 | 4 |
| [Wood](https://harth.build/resources/building-codes/us-states/maryland/ibc-2009/wood.md) | IBC 2009 | 3 |
| [Definitions](https://harth.build/resources/building-codes/us-states/rhode-island/ifc-2009/definitions.md) | IFC 2009 | 3 |
| [Existing Structures](https://harth.build/resources/building-codes/us-states/maryland/ibc-2009/existing-structures.md) | IBC 2009 | 2 |
| [Masonry](https://harth.build/resources/building-codes/us-states/maryland/ibc-2009/masonry.md) | IBC 2009 | 2 |

_7 further chapters mention the term._

### The term in use

How the code actually writes about fire wall, quoted from the 2009 text hosted here:

> Where a fire wall also separates occupancies that are required to be separated by a fire barrier wall, the most restrictive requirements of each separation shall apply.

— [IBC 2009 §706.1](https://harth.build/resources/building-codes/us-states/maryland/ibc-2009/fire-and-smoke-protection-features.md)

> A listed smoke damper designed to resist the passage of smoke shall be provided at each point that a duct or air transfer opening penetrates a fire wall that serves as a horizontal exit.

— [IMC 2009 §607.5.1.1](https://harth.build/resources/building-codes/us-states/new-hampshire/imc-2009/duct-systems.md)

> The height limitation for buildings of Type IIA construction in Groups R-l and R-2 shall be increased to nine stories and 100 feet (30 480 mm) where the building is separated by not less than 50 feet (15 240 mm) from any other building on the lot and from lot lines, the exits are segregated in an area enclosed by …

— [IBC 2009 §509.6](https://harth.build/resources/building-codes/us-states/maryland/ibc-2009/general-building-heights-and-areas.md)

## Fire Wall: 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 | Fire and Smoke Protection Features | |
| Read the definition in the adopted IFC | Definitions | |
| Re-check the requirement that uses it | Fire and Smoke Protection Features (IBC 2009) | |
| Re-check the requirement that uses it | Special Detailed Requirements Based on Use and Occupancy (IBC 2009) | |
| Re-check the requirement that uses it | Duct Systems (IMC 2009) | |
| Re-check the requirement that uses it | Fire Protection Systems (IFC 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)
- [Shaft: Building Code Definition](https://harth.build/resources/glossary/shaft.md)
- [Damper: Building Code Definition](https://harth.build/resources/glossary/damper.md)
- [Fire-resistance Rating: Building Code Definition](https://harth.build/resources/glossary/fire-resistance-rating.md)
- [Fire Barrier: Building Code Definition](https://harth.build/resources/glossary/fire-barrier.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 fire wall?

The International Building Code (IBC) 2009 defines it in Fire and Smoke Protection Features as: “A fire-resistance-rated wall having protected openings, which restricts the spread of fire and extends continuously from the foundation to or through the roof, with sufficient structural stability under fire conditions to allow collapse of construction on either side without collapse of the wall.” 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 fire wall?

In this corpus the term is used across 19 chapters, led by Fire and Smoke Protection Features 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 rules for building a firewall?

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 fire wall, which the IBC 2009 defines as “A fire-resistance-rated wall having protected openings, which restricts the spread of fire and extends continuously from the foundation to or through the roof, with sufficient structural stability under fire conditions to allow collapse of construction on either side without collapse …” — read both before applying either, and confirm the wording in the edition your jurisdiction has adopted.

### What is a fire wall?

In the 2009 I-Codes hosted here it is a defined term rather than a description. The IBC 2009 states, in Fire and Smoke Protection Features: “A fire-resistance-rated wall having protected openings, which restricts the spread of fire and extends continuously from the foundation to or through the roof, with sufficient structural stability under fire conditions to allow collapse of construction on either side without collapse of the wall.” It is defined in IBC 2009, IFC 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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