# Water-reactive Material: Building Code Definition > How the IBC 2009, IFC 2009 define water-reactive material, where the wording differs, and which chapters depend on the term. - Canonical: https://harth.build/resources/glossary/water-reactive-material/ - 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 Use and Occupancy Classification (model text, not a jurisdiction's adopted text) | | Chapters using the term | 6 (counted across the codes hosted here) | | Wording identical across codes | Yes (compare before citing one code's wording under another) | ## Direct answer Water-reactive material is a defined term in the International Building Code (IBC) 2009, in Use and Occupancy Classification. The code's own words are: “A material that explodes; violently reacts; produces flammable, toxic or other hazardous gases; or evolves enough heat to cause autoignition or ignition of combustibles upon exposure to water or moisture. Water-reactive materials are subdivided as follows:” The IFC 2009 carries the same definition word for word, so the term means the same thing in each. The term is used in 6 chapters of this corpus, most often in Use and Occupancy Classification (IBC 2009), Definitions (IFC 2009), Hazardous Materials-general Provisions (IFC 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? **Water-reactive Material** — IBC 2009, Use and Occupancy Classification: > A material that explodes; violently reacts; produces flammable, toxic or other hazardous gases; or evolves enough heat to cause autoignition or ignition of combustibles upon exposure to water or moisture. Water-reactive materials are subdivided as follows: ![Labeled code-term definition diagram: Water-reactive Material: Building Code Definition](https://efwwel0vyt9vy5so.public.blob.vercel-storage.com/images/glossary/water-reactive-material/diagram-1344.webp) *How the IBC 2009, IFC 2009 define water-reactive material, 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 **Water-reactive Material**, in identical words. | Code | Where it is defined | Definition | | --- | --- | --- | | IBC 2009 | [Use and Occupancy Classification](https://harth.build/resources/building-codes/us-states/maryland/ibc-2009/use-and-occupancy-classification.md) | A material that explodes; violently reacts; produces flammable, toxic or other hazardous gases; or evolves enough heat to cause autoignition or ignition of combustibles upon exposure to water or moisture. Water-reactive materials are subdivided as follows: | | IFC 2009 | [Water-reactive Solids and Liquids](https://harth.build/resources/building-codes/us-states/rhode-island/ifc-2009/water-reactive-solids-and-liquids.md) | A material that explodes; violently reacts; produces flammable, toxic or other hazardous gases; or evolves enough heat to cause autoignition or ignition of combustibles upon exposure to water or moisture. Water-reactive materials are subdivided as follows: | ## Where water-reactive material is used in the code The term appears in 6 chapters of the 2009 I-Codes hosted here. The chapters that lean on it hardest are the ones to read next. | Chapter | Code | Mentions | | --- | --- | --- | | [Use and Occupancy Classification](https://harth.build/resources/building-codes/us-states/maryland/ibc-2009/use-and-occupancy-classification.md) | IBC 2009 | 7 | | [Definitions](https://harth.build/resources/building-codes/us-states/rhode-island/ifc-2009/definitions.md) | IFC 2009 | 7 | | [Hazardous Materials-general Provisions](https://harth.build/resources/building-codes/us-states/rhode-island/ifc-2009/hazardous-materials-general-provisions.md) | IFC 2009 | 4 | | [Water-reactive Solids and Liquids](https://harth.build/resources/building-codes/us-states/rhode-island/ifc-2009/water-reactive-solids-and-liquids.md) | IFC 2009 | 4 | | [Definitions](https://harth.build/resources/building-codes/us-states/maryland/ibc-2009/definitions.md) | IBC 2009 | 1 | | [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 | 1 | ## The terms water-reactive material 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 water-reactive material covers: - **[Toxic](https://harth.build/resources/glossary/toxic.md)** — IBC 2009: A chemical falling within any of the following categories: ## Water-reactive Material: 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 | Use and Occupancy Classification | | | Read the definition in the adopted IFC | Water-reactive Solids and Liquids | | | Re-check the requirement that uses it | Use and Occupancy Classification (IBC 2009) | | | Re-check the requirement that uses it | Definitions (IFC 2009) | | | Re-check the requirement that uses it | Hazardous Materials-general Provisions (IFC 2009) | | | Re-check the requirement that uses it | Water-reactive Solids and Liquids (IFC 2009) | | | Confirm the dependent definition | Toxic | | | 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) - [Toxic: Building Code Definition](https://harth.build/resources/glossary/toxic.md) - [Corrosive: Building Code Definition](https://harth.build/resources/glossary/corrosive.md) - [Hazardous Materials: Building Code Definition](https://harth.build/resources/glossary/hazardous-materials.md) - [Combustible Liquid: Building Code Definition](https://harth.build/resources/glossary/combustible-liquid.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 water-reactive material? The International Building Code (IBC) 2009 defines it in Use and Occupancy Classification as: “A material that explodes; violently reacts; produces flammable, toxic or other hazardous gases; or evolves enough heat to cause autoignition or ignition of combustibles upon exposure to water or moisture. Water-reactive materials are subdivided as follows:” 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 water-reactive material? In this corpus the term is used across 6 chapters, led by Use and Occupancy Classification 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. --- - Continue in Harth (open this topic in the Harth agent): https://app.harth.build/agent?context=%2Fresources%2Fglossary%2Fwater-reactive-material%2F - View this page in a browser: https://harth.build/resources/glossary/water-reactive-material/ - All resources for agents: https://harth.build/llms.txt