Building Code Glossary
Dangerous: Building Code Definition
How the IBC 2009 define dangerous, 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
Dangerous is a defined term in the International Building Code (IBC) 2009, in Existing Structures. The code's own words are: “Any building or structure or portion thereof that meets any of the conditions described below shall be deemed dangerous:” 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 29 chapters of this corpus, most often in Hazardous Materials-general Provisions (IFC 2009), Existing Structures (IBC 2009), Flammable Finishes (IFC 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, Harth founder and architectural technology specialist · Published 2026-09-07 · Updated 2026-09-07.
What does this term mean?
Dangerous — IBC 2009, Existing Structures:
Any building or structure or portion thereof that meets any of the conditions described below shall be deemed dangerous:
What must be verified before using this guidance?
Dangerous is defined once in this corpus, in the Existing Structures chapter of the International Building Code (IBC) 2009:
Any building or structure or portion thereof that meets any of the conditions described below shall be deemed dangerous:
Where dangerous is used in the code
The term appears in 29 chapters of the 2009 I-Codes hosted here. The chapters that lean on it hardest are the ones to read next.
| Chapter | Code | Mentions |
|---|---|---|
| Hazardous Materials-general Provisions | IFC 2009 | 13 |
| Existing Structures | IBC 2009 | 10 |
| Flammable Finishes | IFC 2009 | 8 |
| Scope and Administration | IFC 2009 | 6 |
| Explosives and Fireworks | IFC 2009 | 5 |
| Special Detailed Requirements Based on Use and Occupancy | IBC 2009 | 4 |
| Scope and Administration | IBC 2009 | 3 |
| Highly Toxic and Toxic Materials | IFC 2009 | 3 |
| Semiconductor Fabrication Facilities | IFC 2009 | 3 |
| Exhaust Systems | IMC 2009 | 3 |
| Scope and Administration | IMC 2009 | 3 |
| Scope and Administration | IPC 2009 | 3 |
17 further chapters mention the term.
The term in use
How the code actually writes about dangerous, quoted from the 2009 text hosted here:
Prevention, control and mitigation of dangerous conditions related to storage, dispensing, use and handling of hazardous materials shall be in accordance with this chapter.
Materials already in use in a building in compliance with requirements or approvals in effect at the time of their erection or installation shall be permitted to remain in use unless determined by the building code official to be dangerous to life, health or safety.
Flammable vapor areas shall be provided with mechanical ventilation adequate to prevent the dangerous accumulation of vapors.
The terms dangerous is built out of
The definition above leans on 3 other defined terms. Each carries its own code definition, and a local amendment to any of them changes what dangerous covers:
- Structure — IPC 2009: That which is built or constructed or a portion thereof.
- Building — IBC 2009: Any structure used or intended for supporting or sheltering any use or occupancy.
- Shall — IRC 2009: The term, when used in the code, is construed as mandatory.
Dangerous: 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 | Existing Structures | |
| Re-check the requirement that uses it | Hazardous Materials-general Provisions (IFC 2009) | |
| Re-check the requirement that uses it | Existing Structures (IBC 2009) | |
| Re-check the requirement that uses it | Flammable Finishes (IFC 2009) | |
| Re-check the requirement that uses it | Scope and Administration (IFC 2009) | |
| Confirm the dependent definition | Structure | |
| Confirm the dependent definition | Building | |
| 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
- Structure: Building Code Definition
- Building: 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 dangerous?
The International Building Code (IBC) 2009 defines it in Existing Structures as: “Any building or structure or portion thereof that meets any of the conditions described below shall be deemed dangerous:” 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 dangerous?
In this corpus the term is used across 29 chapters, led by Hazardous Materials-general Provisions in the IFC 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 the definition of a dangerous building?
In the 2009 I-Codes hosted here it is a defined term rather than a description. The IBC 2009 states, in Existing Structures: “Any building or structure or portion thereof that meets any of the conditions described below shall be deemed dangerous:” It is defined in IBC 2009. It is not the same as Building, which the IBC 2009 defines separately as “Any structure used or intended for supporting or sheltering any use or occupancy.” 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.
What does IBC mean in building codes?
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 dangerous, which the IBC 2009 defines as “Any building or structure or portion thereof that meets any of the conditions described below shall be deemed dangerous:” — read both before applying either, and confirm the wording in the edition your jurisdiction has adopted.
What is the full meaning of dangerous?
In the 2009 I-Codes hosted here it is a defined term rather than a description. The IBC 2009 states, in Existing Structures: “Any building or structure or portion thereof that meets any of the conditions described below shall be deemed dangerous:” 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.
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