# Occupancy Category: Building Code Definition

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

- Canonical: https://harth.build/resources/glossary/occupancy-category/
- 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 Structural Design (model text, not a jurisdiction's adopted text) |
| Chapters using the term | 9 (counted across the codes hosted here) |
| Wording identical across codes | Single code (compare before citing one code's wording under another) |

## Direct answer

Occupancy category is a defined term in the International Building Code (IBC) 2009, in Structural Design. The code's own words are: “A category used to determine structural requirements based on occupancy.” 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 9 chapters of this corpus, most often in Structural Design (IBC 2009), Structural Tests and Special Inspections (IBC 2009), Existing Structures (IBC 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?

**Occupancy Category** — IBC 2009, Structural Design:

> A category used to determine structural requirements based on occupancy.

![Labeled code-term definition diagram: Occupancy Category: Building Code Definition](https://efwwel0vyt9vy5so.public.blob.vercel-storage.com/images/glossary/occupancy-category/diagram-1344.webp)

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

## What must be verified before using this guidance?

**Occupancy Category** is defined once in this corpus, in the [Structural Design](https://harth.build/resources/building-codes/us-states/maryland/ibc-2009/structural-design.md) chapter of the International Building Code (IBC) 2009:

> A category used to determine structural requirements based on occupancy.

## Where occupancy category is used in the code

The term appears in 9 chapters of the 2009 I-Codes hosted here. The chapters that lean on it hardest are the ones to read next.

| Chapter | Code | Mentions |
| --- | --- | --- |
| [Structural Design](https://harth.build/resources/building-codes/us-states/maryland/ibc-2009/structural-design.md) | IBC 2009 | 35 |
| [Structural Tests and Special Inspections](https://harth.build/resources/building-codes/us-states/maryland/ibc-2009/structural-tests-and-special-inspections.md) | IBC 2009 | 18 |
| [Existing Structures](https://harth.build/resources/building-codes/us-states/maryland/ibc-2009/existing-structures.md) | IBC 2009 | 4 |
| [Soils and Foundations](https://harth.build/resources/building-codes/us-states/maryland/ibc-2009/soils-and-foundations.md) | IBC 2009 | 3 |
| [Masonry](https://harth.build/resources/building-codes/us-states/maryland/ibc-2009/masonry.md) | IBC 2009 | 2 |
| [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 | 2 |
| [Definitions](https://harth.build/resources/building-codes/us-states/maryland/ibc-2009/definitions.md) | IBC 2009 | 1 |
| [Wood](https://harth.build/resources/building-codes/us-states/maryland/ibc-2009/wood.md) | IBC 2009 | 1 |
| [Definitions](https://harth.build/resources/building-codes/us-states/maryland/irc-2009/definitions.md) | IRC 2009 | 1 |

### The term in use

How the code actually writes about occupancy category, quoted from the 2009 text hosted here:

> Each building and structure shall be assigned an occupancy category in accordance with Table 1604.5.

— [IBC 2009 §1604.5](https://harth.build/resources/building-codes/us-states/maryland/ibc-2009/structural-design.md)

> Masonry construction shall be inspected and verified in accordance with the requirements of Sections 1704.5.1 through 1704.5.3, depending on the occupancy category of the building or structure.

— [IBC 2009 §1704.5](https://harth.build/resources/building-codes/us-states/maryland/ibc-2009/structural-tests-and-special-inspections.md)

> When a change of occupancy results in a structure being reclassified to a higher occupancy category, the structure shall conform to the seismic requirements for a new structure of the higher occupancy category.

— [IBC 2009 §3408.4](https://harth.build/resources/building-codes/us-states/maryland/ibc-2009/existing-structures.md)


## The terms occupancy category 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 occupancy category covers:

- **[Occupancy](https://harth.build/resources/glossary/occupancy.md)** — IMC 2009: The purpose for which a building, or portion thereof, is utilized or occupied.

## Occupancy Category: 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 | Structural Design | |
| Re-check the requirement that uses it | Structural Design (IBC 2009) | |
| Re-check the requirement that uses it | Structural Tests and Special Inspections (IBC 2009) | |
| Re-check the requirement that uses it | Existing Structures (IBC 2009) | |
| Re-check the requirement that uses it | Soils and Foundations (IBC 2009) | |
| Confirm the dependent definition | Occupancy | |
| 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)
- [Occupancy: Building Code Definition](https://harth.build/resources/glossary/occupancy.md)
- [Design Flood Elevation: Building Code Definition](https://harth.build/resources/glossary/design-flood-elevation.md)
- [Loads: Building Code Definition](https://harth.build/resources/glossary/loads.md)
- [Seismic Design Category: Building Code Definition](https://harth.build/resources/glossary/seismic-design-category.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 occupancy category?

The International Building Code (IBC) 2009 defines it in Structural Design as: “A category used to determine structural requirements based on occupancy.” 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 occupancy category?

In this corpus the term is used across 9 chapters, led by Structural Design 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 are the different occupancy classifications in the North Carolina building code?

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 occupancy category, which the IBC 2009 defines as “A category used to determine structural requirements based on occupancy.” — read both before applying either, and confirm the wording in the edition your jurisdiction has adopted.

### What is the IBC occupancy classification?

Occupancy Classification is a separate defined term. The IFC 2009 defines it as: “For the purposes of this code, certain occupancies are defined as follows:” That is not the same as occupancy category, which the IBC 2009 defines as “A category used to determine structural requirements based on occupancy.” — read both before applying either, and confirm the wording in the edition your jurisdiction has adopted.

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