# Penetration Firestop: Building Code Definition

> How the IBC 2009 define penetration firestop, where the wording differs, and which chapters depend on the term.

- Canonical: https://harth.build/resources/glossary/penetration-firestop/
- 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 (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 | 4 (counted across the codes hosted here) |
| Wording identical across codes | Single code (compare before citing one code's wording under another) |

## Direct answer

Penetration firestop is a defined term in the International Building Code (IBC) 2009, in Fire and Smoke Protection Features. The code's own words are: “A through-penetration firestop or a membrane-penetration firestop.” No other I-Code in this corpus defines it, so the IBC 2009 definition is the one to work from. The term is used in 4 chapters of this corpus, most often in Fire and Smoke Protection Features (IBC 2009), Building Planning (IRC 2009), Exhaust Systems (IMC 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?

**Penetration Firestop** — IBC 2009, Fire and Smoke Protection Features:

> A through-penetration firestop or a membrane-penetration firestop.

![Labeled code-term definition diagram: Penetration Firestop: Building Code Definition](https://efwwel0vyt9vy5so.public.blob.vercel-storage.com/images/glossary/penetration-firestop/diagram-1344.webp)

*How the IBC 2009 define penetration firestop, where the wording differs, and which chapters depend on the term.*

## What must be verified before using this guidance?

**Penetration Firestop** is defined once in this corpus, in the [Fire and Smoke Protection Features](https://harth.build/resources/building-codes/us-states/maryland/ibc-2009/fire-and-smoke-protection-features.md) chapter of the International Building Code (IBC) 2009:

> A through-penetration firestop or a membrane-penetration firestop.

## Where penetration firestop 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 |
| --- | --- | --- |
| [Fire and Smoke Protection Features](https://harth.build/resources/building-codes/us-states/maryland/ibc-2009/fire-and-smoke-protection-features.md) | IBC 2009 | 25 |
| [Building Planning](https://harth.build/resources/building-codes/us-states/maryland/irc-2009/building-planning.md) | IRC 2009 | 6 |
| [Exhaust Systems](https://harth.build/resources/building-codes/us-states/new-hampshire/imc-2009/exhaust-systems.md) | IMC 2009 | 4 |
| [Definitions](https://harth.build/resources/building-codes/us-states/maryland/ibc-2009/definitions.md) | IBC 2009 | 3 |

### The term in use

How the code actually writes about penetration firestop, quoted from the 2009 text hosted here:

> Through penetrations shall be protected by an approved penetration firestop system installed as tested in accordance with ASTM E 814 or UL 1479, with a minimum positive pressure differential of 0.01 inch (2.49 Pa) of water and shall have an F rating of not less than the required fire-resistance rating of the wall penetrated.

— [IBC 2009 §713.3.1.2](https://harth.build/resources/building-codes/us-states/maryland/ibc-2009/fire-and-smoke-protection-features.md)

> Penetrations shall be protected by an approved penetration firestop system installed as tested in accordance with ASTM E 814 or UL 1479, with a minimum positive pressure differential of 0.01 inch of water (3 Pa) and shall have an F rating of not less than the required fire-resistance rating of the wall or floorlceiling assembly penetrated.

— [IRC 2009 §R302.4.1.2](https://harth.build/resources/building-codes/us-states/maryland/irc-2009/building-planning.md)

> Duct penetrations shall be protected with a through-penetration firestop system classified in accordance with ASTM E 814 or UL 1479 and having an "F" and "T" rating equal to the fire-resistance rating of the assembly being penetrated.

— [IMC 2009 §506.3.10.2](https://harth.build/resources/building-codes/us-states/new-hampshire/imc-2009/exhaust-systems.md)


## The terms penetration firestop is built out of

The definition above leans on 1 other defined term. Each carries its own code definition, and a local amendment to any of them changes what penetration firestop covers:

- **[Membrane-penetration Firestop](https://harth.build/resources/glossary/membrane-penetration-firestop.md)** — IBC 2009: A material, device or construction installed to resist for a prescribed time period the passage of flame and heat through openings in a protective membrane in order to accommodate cables, cable trays, conduit, tubing, pipes or similar items.

## Penetration Firestop: 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 | |
| Re-check the requirement that uses it | Fire and Smoke Protection Features (IBC 2009) | |
| Re-check the requirement that uses it | Building Planning (IRC 2009) | |
| Re-check the requirement that uses it | Exhaust Systems (IMC 2009) | |
| Re-check the requirement that uses it | Definitions (IBC 2009) | |
| Confirm the dependent definition | Membrane-penetration Firestop | |
| 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)
- [Membrane-penetration Firestop: Building Code Definition](https://harth.build/resources/glossary/membrane-penetration-firestop.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)

## 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 penetration firestop?

The International Building Code (IBC) 2009 defines it in Fire and Smoke Protection Features as: “A through-penetration firestop or a membrane-penetration firestop.” 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 penetration firestop?

In this corpus the term is used across 4 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.

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