Building Code Glossary
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.
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.
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, 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:
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 | 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 | 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 | IBC 2009 | 7 |
| Definitions | IFC 2009 | 7 |
| Hazardous Materials-general Provisions | IFC 2009 | 4 |
| Water-reactive Solids and Liquids | IFC 2009 | 4 |
| Definitions | IBC 2009 | 1 |
| Special Detailed Requirements Based on Use and Occupancy | 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 — 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 and the ICC 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
- Toxic: Building Code Definition
- Corrosive: Building Code Definition
- Hazardous Materials: Building Code Definition
- Combustible Liquid: Building Code Definition
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 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.
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