# Refrigeration System Classification: Building Code Definition

> How the IMC 2009 define refrigeration system classification, where the wording differs, and which chapters depend on the term.

- Canonical: https://harth.build/resources/glossary/refrigeration-system-classification/
- 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 | IMC 2009 (2009 editions transcribed in this corpus) |
| Primary source | IMC 2009 Definitions (model text, not a jurisdiction's adopted text) |
| Chapters using the term | 2 (counted across the codes hosted here) |
| Wording identical across codes | Single code (compare before citing one code's wording under another) |

## Direct answer

Refrigeration system classification is a defined term in the International Mechanical Code (IMC) 2009, in Definitions. The code's own words are: “Refrigeration systems are classified according to the degree of probability that leaked refrigerant from a failed connection, seal or component will enter an occupied area. The distinction is based on the basic design or location of the components.” No other I-Code in this corpus defines it, so the IMC 2009 definition is the one to work from. The term is used in 2 chapters of this corpus, most often in Definitions (IMC 2009), Refrigeration (IMC 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?

**Refrigeration System Classification** — IMC 2009, Definitions:

> Refrigeration systems are classified according to the degree of probability that leaked refrigerant from a failed connection, seal or component will enter an occupied area. The distinction is based on the basic design or location of the components.

![Labeled code-term definition diagram: Refrigeration System Classification: Building Code Definition](https://efwwel0vyt9vy5so.public.blob.vercel-storage.com/images/glossary/refrigeration-system-classification/diagram-1344.webp)

*How the IMC 2009 define refrigeration system classification, where the wording differs, and which chapters depend on the term.*

## What must be verified before using this guidance?

**Refrigeration System Classification** is defined once in this corpus, in the [Definitions](https://harth.build/resources/building-codes/us-states/new-hampshire/imc-2009/definitions.md) chapter of the International Mechanical Code (IMC) 2009:

> Refrigeration systems are classified according to the degree of probability that leaked refrigerant from a failed connection, seal or component will enter an occupied area. The distinction is based on the basic design or location of the components.

## Where refrigeration system classification is used in the code

The term appears in 2 chapters of the 2009 I-Codes hosted here. The chapters that lean on it hardest are the ones to read next.

| Chapter | Code | Mentions |
| --- | --- | --- |
| [Definitions](https://harth.build/resources/building-codes/us-states/new-hampshire/imc-2009/definitions.md) | IMC 2009 | 1 |
| [Refrigeration](https://harth.build/resources/building-codes/us-states/new-hampshire/imc-2009/refrigeration.md) | IMC 2009 | 1 |

## The terms refrigeration system classification 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 refrigeration system classification covers:

- **[Refrigerant](https://harth.build/resources/glossary/refrigerant.md)** — IRC 2009: A substance used to produce refrigeration by its expansion or evaporation.

## Refrigeration System Classification: 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 IMC | Definitions | |
| Re-check the requirement that uses it | Definitions (IMC 2009) | |
| Re-check the requirement that uses it | Refrigeration (IMC 2009) | |
| Confirm the dependent definition | Refrigerant | |
| 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)
- [Refrigerant: Building Code Definition](https://harth.build/resources/glossary/refrigerant.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)

## 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 refrigeration system classification?

The International Mechanical Code (IMC) 2009 defines it in Definitions as: “Refrigeration systems are classified according to the degree of probability that leaked refrigerant from a failed connection, seal or component will enter an occupied area. The distinction is based on the basic design or location of the components.” 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 refrigeration system classification?

In this corpus the term is used across 2 chapters, led by Definitions 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.

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