Building Code Glossary
Refrigeration System, Mechanical: Building Code Definition
How the IMC 2009 define refrigeration system, mechanical, 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
Refrigeration system, mechanical is a defined term in the International Mechanical Code (IMC) 2009, in Definitions. The code's own words are: “A combination of interconnected refrigeration-containing parts constituting one closed refrigerant circuit in which a refrigerant is circulated for the purpose of extracting heat and in which a compressor is used for compressing the refrigerant vapor.” 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 3 chapters of this corpus, most often in Building Services and Systems (IFC 2009), 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.
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?
Refrigeration System, Mechanical — IMC 2009, Definitions:
A combination of interconnected refrigeration-containing parts constituting one closed refrigerant circuit in which a refrigerant is circulated for the purpose of extracting heat and in which a compressor is used for compressing the refrigerant vapor.
What must be verified before using this guidance?
Refrigeration System, Mechanical is defined once in this corpus, in the Definitions chapter of the International Mechanical Code (IMC) 2009:
A combination of interconnected refrigeration-containing parts constituting one closed refrigerant circuit in which a refrigerant is circulated for the purpose of extracting heat and in which a compressor is used for compressing the refrigerant vapor.
Where refrigeration system, mechanical is used in the code
The term appears in 3 chapters of the 2009 I-Codes hosted here. The chapters that lean on it hardest are the ones to read next.
| Chapter | Code | Mentions |
|---|---|---|
| Building Services and Systems | IFC 2009 | 1 |
| Definitions | IMC 2009 | 1 |
| Refrigeration | IMC 2009 | 1 |
Refrigeration System, Mechanical compared with Refrigeration System
These two are the closest pair in the 2009 I-Codes: about 77 per cent of their defining words are the same. The code states both and compares neither, so the difference is worth naming.
| Wording unique to it | |
|---|---|
| Refrigeration System, Mechanical (IMC 2009) | refrigeration, compressor, used, compressing, vapor |
| Refrigeration System (IFC 2009) | — no wording of its own |
Everything else in the two definitions is shared. If a project turns on which of the two applies, those words are the whole of the test — and a local amendment that edits one of them without editing the other moves the boundary between refrigeration system, mechanical and refrigeration system.
The terms refrigeration system, mechanical 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 refrigeration system, mechanical covers:
- Refrigerant — IRC 2009: A substance used to produce refrigeration by its expansion or evaporation.
- Compressor — IMC 2009: A specific machine, with or without accessories, for compressing a gas.
Refrigeration System, Mechanical: 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 IMC | Definitions | |
| Re-check the requirement that uses it | Building Services and Systems (IFC 2009) | |
| 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 | |
| Confirm the dependent definition | Compressor | |
| 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
- Refrigerant: Building Code Definition
- Compressor: 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 refrigeration system, mechanical?
The International Mechanical Code (IMC) 2009 defines it in Definitions as: “A combination of interconnected refrigeration-containing parts constituting one closed refrigerant circuit in which a refrigerant is circulated for the purpose of extracting heat and in which a compressor is used for compressing the refrigerant vapor.” 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, mechanical?
In this corpus the term is used across 3 chapters, led by Building Services and Systems 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 a refrigeration system?
In the 2009 I-Codes hosted here it is a defined term rather than a description. The IMC 2009 states, in Definitions: “A combination of interconnected refrigeration-containing parts constituting one closed refrigerant circuit in which a refrigerant is circulated for the purpose of extracting heat and in which a compressor is used for compressing the refrigerant vapor.” It is defined in IMC 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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