# Lot: Building Code Definition

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

- Canonical: https://harth.build/resources/glossary/lot/
- 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, IRC 2009, IFC 2009 (2009 editions transcribed in this corpus) |
| Primary source | IBC 2009 Definitions (model text, not a jurisdiction's adopted text) |
| Chapters using the term | 80 (counted across the codes hosted here) |
| Wording identical across codes | Yes (compare before citing one code's wording under another) |

## Direct answer

Lot is a defined term in the International Building Code (IBC) 2009, in Definitions. The code's own words are: “A portion or parcel of land considered as a unit.” The IRC 2009, IFC 2009 carry the same definition word for word, so the term means the same thing in each. The term is used in 80 chapters of this corpus, most often in Exhaust Systems (IMC 2009), Fuel Gas (IRC 2009), Flammable and Combustible Liquids (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](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?

**Lot** — IBC 2009, Definitions:

> A portion or parcel of land considered as a unit.

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

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

## What must be verified before using this guidance?

Three of the I-Codes in this corpus define **Lot**, in identical words.

| Code | Where it is defined | Definition |
| --- | --- | --- |
| IBC 2009 | [Definitions](https://harth.build/resources/building-codes/us-states/maryland/ibc-2009/definitions.md) | A portion or parcel of land considered as a unit. |
| IRC 2009 | [Definitions](https://harth.build/resources/building-codes/us-states/maryland/irc-2009/definitions.md) | A portion or parcel of land considered as a unit. |
| IFC 2009 | [Definitions](https://harth.build/resources/building-codes/us-states/rhode-island/ifc-2009/definitions.md) | A portion or parcel of land considered as a unit. |

## Where lot is used in the code

The term appears in 80 chapters of the 2009 I-Codes hosted here. The chapters that lean on it hardest are the ones to read next.

| Chapter | Code | Mentions |
| --- | --- | --- |
| [Exhaust Systems](https://harth.build/resources/building-codes/us-states/new-hampshire/imc-2009/exhaust-systems.md) | IMC 2009 | 44 |
| [Fuel Gas](https://harth.build/resources/building-codes/us-states/maryland/irc-2009/fuel-gas.md) | IRC 2009 | 42 |
| [Flammable and Combustible Liquids](https://harth.build/resources/building-codes/us-states/rhode-island/ifc-2009/flammable-and-combustible-liquids.md) | IFC 2009 | 39 |
| [Fire and Smoke Protection Features](https://harth.build/resources/building-codes/us-states/maryland/ibc-2009/fire-and-smoke-protection-features.md) | IBC 2009 | 35 |
| [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 | 29 |
| [Definitions](https://harth.build/resources/building-codes/us-states/rhode-island/ifc-2009/definitions.md) | IFC 2009 | 23 |
| [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 | 21 |
| [Exhaust Systems](https://harth.build/resources/building-codes/us-states/maryland/irc-2009/exhaust-systems.md) | IRC 2009 | 18 |
| [Building Planning](https://harth.build/resources/building-codes/us-states/maryland/irc-2009/building-planning.md) | IRC 2009 | 13 |
| [General Building Heights and Areas](https://harth.build/resources/building-codes/us-states/maryland/ibc-2009/general-building-heights-and-areas.md) | IBC 2009 | 12 |
| [Definitions](https://harth.build/resources/building-codes/us-states/maryland/irc-2009/definitions.md) | IRC 2009 | 12 |
| [Use and Occupancy Classification](https://harth.build/resources/building-codes/us-states/maryland/ibc-2009/use-and-occupancy-classification.md) | IBC 2009 | 9 |

_68 further chapters mention the term._

### The term in use

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

> Vent outlets shall be located such that flammable vapors will not be trapped by eaves or other obstructions and shall be at least 5 feet (1524 mm) from building openings or lot lines of properties that can be built upon.

— [IFC 2009 §3404.2.7.3.3](https://harth.build/resources/building-codes/us-states/rhode-island/ifc-2009/flammable-and-combustible-liquids.md)

> For the purposes of determining the required wall and opening protection and roof-covering requirements, buildings on the same lot shall be assumed to have an imaginary line between them.

— [IBC 2009 §705.3](https://harth.build/resources/building-codes/us-states/maryland/ibc-2009/fire-and-smoke-protection-features.md)

> The distance to an adjacent lot line shall be determined in accordance with Table 602 and Section 705.

— [IBC 2009 §406.3.7](https://harth.build/resources/building-codes/us-states/maryland/ibc-2009/special-detailed-requirements-based-on-use-and-occupancy.md)

## Lot: 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 | Definitions | |
| Read the definition in the adopted IRC | Definitions | |
| Read the definition in the adopted IFC | Definitions | |
| Re-check the requirement that uses it | Exhaust Systems (IMC 2009) | |
| Re-check the requirement that uses it | Fuel Gas (IRC 2009) | |
| Re-check the requirement that uses it | Flammable and Combustible Liquids (IFC 2009) | |
| Re-check the requirement that uses it | Fire and Smoke Protection Features (IBC 2009) | |
| 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)
- [Building: Building Code Definition](https://harth.build/resources/glossary/building.md)
- [Construction Documents: Building Code Definition](https://harth.build/resources/glossary/construction-documents.md)
- [Registered Design Professional: Building Code Definition](https://harth.build/resources/glossary/registered-design-professional.md)
- [Dwelling Unit: Building Code Definition](https://harth.build/resources/glossary/dwelling-unit.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 lot?

The International Building Code (IBC) 2009 defines it in Definitions as: “A portion or parcel of land considered as a unit.” 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.

### Do the I-Codes define lot the same way?

In the 2009 editions transcribed here, yes: IBC 2009, IRC 2009, IFC 2009 carry the same wording, so the term means the same thing in each. Later editions do diverge on some terms, so confirm against the adopted edition rather than assuming the alignment holds.

### Which parts of the code depend on lot?

In this corpus the term is used across 80 chapters, led by Exhaust Systems in the IMC 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 legal definition of a lot?

In the 2009 I-Codes hosted here it is a defined term rather than a description. The IBC 2009 states, in Definitions: “A portion or parcel of land considered as a unit.” It is defined in IBC 2009, IRC 2009, IFC 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.

### 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 lot, which the IBC 2009 defines as “A portion or parcel of land considered as a unit.” — read both before applying either, and confirm the wording in the edition your jurisdiction has adopted.

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