# Through-penetration Firestop System: Building Code Definition > How the IBC 2009 define through-penetration firestop system, where the wording differs, and which chapters depend on the term. - Canonical: https://harth.build/resources/glossary/through-penetration-firestop-system/ - 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 | 3 (counted across the codes hosted here) | | Wording identical across codes | Single code (compare before citing one code's wording under another) | ## Direct answer Through-penetration firestop system is a defined term in the International Building Code (IBC) 2009, in Fire and Smoke Protection Features. The code's own words are: “An assemblage of specific materials or products that are designed, tested and fire-resistance rated to resist for a prescribed period of time the spread of fire through penetrations. The F and T Irating criteria for penetration firestop systems shall be in accordance with ASTM E 814 or UL 1479. See definitions of "F rating" and …” 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 3 chapters of this corpus, most often in Fire and Smoke Protection Features (IBC 2009), Exhaust Systems (IMC 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. *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? **Through-penetration Firestop System** — IBC 2009, Fire and Smoke Protection Features: > An assemblage of specific materials or products that are designed, tested and fire-resistance rated to resist for a prescribed period of time the spread of fire through penetrations. The F and T Irating criteria for penetration firestop systems shall be in accordance with ASTM E 814 or UL 1479. See definitions of "F rating" and "T rating." ![Labeled code-term definition diagram: Through-penetration Firestop System: Building Code Definition](https://efwwel0vyt9vy5so.public.blob.vercel-storage.com/images/glossary/through-penetration-firestop-system/diagram-1344.webp) *How the IBC 2009 define through-penetration firestop system, where the wording differs, and which chapters depend on the term.* ## What must be verified before using this guidance? **Through-penetration Firestop System** 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: > An assemblage of specific materials or products that are designed, tested and fire-resistance rated to resist for a prescribed period of time the spread of fire through penetrations. The F and T Irating criteria for penetration firestop systems shall be in accordance with ASTM E 814 or UL 1479. See definitions of "F rating" and "T rating." ## Where through-penetration firestop system is used in the code The term appears in 3 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 | 13 | | [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 | 1 | ### The term in use How the code actually writes about through-penetration firestop system, quoted from the 2009 text hosted here: > 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 time period that the through-penetration firestop system limits the spread of fire through the penetration when tested in accordance with ASTM E 814 or UL 1479. — [IBC 2009, Fire and Smoke Protection Features](https://harth.build/resources/building-codes/us-states/maryland/ibc-2009/fire-and-smoke-protection-features.md) ## Through-penetration Firestop System compared with Fire-resistant Joint System These two are the closest pair in the 2009 I-Codes: about 56 per cent of their defining words are the same. The code states both and compares neither, so the difference is worth naming. | | Wording unique to it | | --- | --- | | **Through-penetration Firestop System** (IBC 2009) | spread, penetrations, f, t, irating, criteria, penetration, firestop, systems, 814, 1479, see | | [Fire-resistant Joint System](https://harth.build/resources/glossary/fire-resistant-joint-system.md) (IBC 2009) | either, 1966, 2079, passage, joints, made, between, assemblies | Everything else in the two definitions is shared. If a project turns on which of the two applies, those words are the whole of the test — and a local amendment that edits one of them without editing the other moves the boundary between through-penetration firestop system and fire-resistant joint system. ## The terms through-penetration firestop system is built out of The definition above leans on 2 other defined terms. Each carries its own code definition, and a local amendment to any of them changes what through-penetration firestop system covers: - **[Penetration Firestop](https://harth.build/resources/glossary/penetration-firestop.md)** — IBC 2009: A through-penetration firestop or a membrane-penetration firestop. - **[Shall](https://harth.build/resources/glossary/shall.md)** — IRC 2009: The term, when used in the code, is construed as mandatory. ## Through-penetration Firestop System: 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 | Exhaust Systems (IMC 2009) | | | Re-check the requirement that uses it | Definitions (IBC 2009) | | | Confirm the dependent definition | Penetration Firestop | | | Confirm the dependent definition | Shall | | | 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) - [Penetration Firestop: Building Code Definition](https://harth.build/resources/glossary/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 through-penetration firestop system? The International Building Code (IBC) 2009 defines it in Fire and Smoke Protection Features as: “An assemblage of specific materials or products that are designed, tested and fire-resistance rated to resist for a prescribed period of time the spread of fire through penetrations. The F and T Irating criteria for penetration firestop systems shall be in accordance with ASTM E 814 or UL 1479. See definitions of "F rating" and "T rating."” 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 through-penetration firestop system? In this corpus the term is used across 3 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 is a through-penetration firestop system? 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: “An assemblage of specific materials or products that are designed, tested and fire-resistance rated to resist for a prescribed period of time the spread of fire through penetrations. The F and T Irating criteria for penetration firestop systems shall be in accordance with ASTM E 814 or UL 1479. See definitions of "F rating" and …” It is defined in IBC 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. --- - Continue in Harth (open this topic in the Harth agent): https://app.harth.build/agent?context=%2Fresources%2Fglossary%2Fthrough-penetration-firestop-system%2F - View this page in a browser: https://harth.build/resources/glossary/through-penetration-firestop-system/ - All resources for agents: https://harth.build/llms.txt