# Isolated: Building Code Definition

> How the IRC 2009 define isolated, where the wording differs, and which chapters depend on the term.

- Canonical: https://harth.build/resources/glossary/isolated/
- 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 | IRC 2009 (2009 editions transcribed in this corpus) |
| Primary source | IRC 2009 Electrical Definitions (model text, not a jurisdiction's adopted text) |
| Chapters using the term | 37 (counted across the codes hosted here) |
| Wording identical across codes | Single code (compare before citing one code's wording under another) |

## Direct answer

Isolated is a defined term in the International Residential Code (IRC) 2009, in Electrical Definitions. The code's own words are: “(As applied to location.) Not readily accessible to persons unless special means for access are used.” No other I-Code in this corpus defines it, so the IRC 2009 definition is the one to work from. The term is used in 37 chapters of this corpus, most often in Soils and Foundations (IBC 2009), Building Planning (IRC 2009), Masonry (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?

**Isolated** — IRC 2009, Electrical Definitions:

> (As applied to location.) Not readily accessible to persons unless special means for access are used.

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

*How the IRC 2009 define isolated, where the wording differs, and which chapters depend on the term.*

## What must be verified before using this guidance?

**Isolated** is defined once in this corpus, in the [Electrical Definitions](https://harth.build/resources/building-codes/us-states/maryland/irc-2009/electrical-definitions.md) chapter of the International Residential Code (IRC) 2009:

> (As applied to location.) Not readily accessible to persons unless special means for access are used.

## Where isolated is used in the code

The term appears in 37 chapters of the 2009 I-Codes hosted here. The chapters that lean on it hardest are the ones to read next.

| Chapter | Code | Mentions |
| --- | --- | --- |
| [Soils and Foundations](https://harth.build/resources/building-codes/us-states/maryland/ibc-2009/soils-and-foundations.md) | IBC 2009 | 19 |
| [Building Planning](https://harth.build/resources/building-codes/us-states/maryland/irc-2009/building-planning.md) | IRC 2009 | 14 |
| [Masonry](https://harth.build/resources/building-codes/us-states/maryland/ibc-2009/masonry.md) | IBC 2009 | 10 |
| [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 | 10 |
| [Swimming Pools](https://harth.build/resources/building-codes/us-states/maryland/irc-2009/swimming-pools.md) | IRC 2009 | 9 |
| [Structural Design](https://harth.build/resources/building-codes/us-states/maryland/ibc-2009/structural-design.md) | IBC 2009 | 8 |
| [Interior Environment](https://harth.build/resources/building-codes/us-states/maryland/ibc-2009/interior-environment.md) | IBC 2009 | 7 |
| [Fuel Gas](https://harth.build/resources/building-codes/us-states/maryland/irc-2009/fuel-gas.md) | IRC 2009 | 7 |
| [Wall Construction](https://harth.build/resources/building-codes/us-states/maryland/irc-2009/wall-construction.md) | IRC 2009 | 7 |
| [Fire Protection Systems](https://harth.build/resources/building-codes/us-states/rhode-island/ifc-2009/fire-protection-systems.md) | IFC 2009 | 6 |
| [Refrigeration](https://harth.build/resources/building-codes/us-states/new-hampshire/imc-2009/refrigeration.md) | IMC 2009 | 6 |
| [Motor Fuel-dispensing Facilities and Repair Garages](https://harth.build/resources/building-codes/us-states/rhode-island/ifc-2009/motor-fuel-dispensing-facilities-and-repair-garages.md) | IFC 2009 | 5 |

_25 further chapters mention the term._

### The term in use

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

> Isolated poles for uses such as flagpoles or signs and poles used to support buildings that are not adversely affected by a 1/2 inch (12.7 mm) motion at the ground surface due to short-term lateral loads shall be permitted to be designed using lateral bearing pressures equal to two times the tabular values.

— [IBC 2009 §1806.3.4](https://harth.build/resources/building-codes/us-states/maryland/ibc-2009/soils-and-foundations.md)

> In areas designated in Table R301.2(1) as having local historical data documenting structural damage to buildings caused by wind speed-up at isolated hills, ridges and escarpments that are abrupt changes from the general topography of the area, topographic wind effects shall be considered in the design of the building in accordance with Section R30 1.2.1.5.1 or in accordance with the …

— [IRC 2009 §R301.2.1.5](https://harth.build/resources/building-codes/us-states/maryland/irc-2009/building-planning.md)

> Adobe units shall not be used for isolated piers or columns in a load-bearing capacity.

— [IBC 2009 §2109.3.4.4](https://harth.build/resources/building-codes/us-states/maryland/ibc-2009/masonry.md)


## The terms isolated 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 isolated covers:

- **[Readily Accessible](https://harth.build/resources/glossary/readily-accessible.md)** — IECC 2009: Capable of being reached quickly for operation, renewal or inspection without requiring those to whom ready access is requisite to climb over or remove obstacles or to resort to portable ladders or access equipment (see "Accessible").
- **[Accessible](https://harth.build/resources/glossary/accessible.md)** — IBC 2009: A site, building, facilityor portion thereof that complies with this chapter.

## Isolated: 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 IRC | Electrical Definitions | |
| Re-check the requirement that uses it | Soils and Foundations (IBC 2009) | |
| Re-check the requirement that uses it | Building Planning (IRC 2009) | |
| Re-check the requirement that uses it | Masonry (IBC 2009) | |
| Re-check the requirement that uses it | Special Detailed Requirements Based on Use and Occupancy (IBC 2009) | |
| Confirm the dependent definition | Readily Accessible | |
| Confirm the dependent definition | Accessible | |
| 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)
- [Readily Accessible: Building Code Definition](https://harth.build/resources/glossary/readily-accessible.md)
- [Accessible: Building Code Definition](https://harth.build/resources/glossary/accessible.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 isolated?

The International Residential Code (IRC) 2009 defines it in Electrical Definitions as: “(As applied to location.) Not readily accessible to persons unless special means for access are used.” 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 isolated?

In this corpus the term is used across 37 chapters, led by Soils and Foundations 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 types of 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 isolated, which the IRC 2009 defines as “(As applied to location.) Not readily accessible to persons unless special means for access are used.” — read both before applying either, and confirm the wording in the edition your jurisdiction has adopted.

### What does isolated mean?

In the 2009 I-Codes hosted here it is a defined term rather than a description. The IRC 2009 states, in Electrical Definitions: “(As applied to location.) Not readily accessible to persons unless special means for access are used.” It is defined in IRC 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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