Building Code Glossary
Ground Source Heat Pump Loop System: Building Code Definition
How the IMC 2009 define ground source heat pump loop system, 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
Ground source heat pump loop system is a defined term in the International Mechanical Code (IMC) 2009, in Definitions. The code's own words are: “Piping buried in horizontal or vertical excavations or placed in a body of water for the purpose of transporting heat transfer liquid to and from a heat pump. Included in this definition are closed loop systems in which the liquid is recirculated and open loop systems in which the liquid is drawn from a well …” 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 Hydronic Piping (IMC 2009), Hvdronic Piping (IRC 2009), Definitions (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?
Ground Source Heat Pump Loop System — IMC 2009, Definitions:
Piping buried in horizontal or vertical excavations or placed in a body of water for the purpose of transporting heat transfer liquid to and from a heat pump. Included in this definition are closed loop systems in which the liquid is recirculated and open loop systems in which the liquid is drawn from a well or other source.
What must be verified before using this guidance?
Ground Source Heat Pump Loop System is defined once in this corpus, in the Definitions chapter of the International Mechanical Code (IMC) 2009:
Piping buried in horizontal or vertical excavations or placed in a body of water for the purpose of transporting heat transfer liquid to and from a heat pump. Included in this definition are closed loop systems in which the liquid is recirculated and open loop systems in which the liquid is drawn from a well or other source.
Where ground source heat pump loop system 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 |
|---|---|---|
| Hydronic Piping | IMC 2009 | 5 |
| Hvdronic Piping | IRC 2009 | 4 |
| Definitions | IMC 2009 | 1 |
The terms ground source heat pump loop system is built out of
The definition above leans on 4 other defined terms. Each carries its own code definition, and a local amendment to any of them changes what ground source heat pump loop system covers:
- Heat Transfer Liquid — IMC 2009: The operating or thermal storage liquid in a mechanical system, including water or other liquid base, and additives at the concentration present under
- Heat Pump — IRC 2009: An appliance having heating or heating/cooling capability and that uses refrigerants to extract heat from air, liquid or other sources.
- Liquid — IBC 2009: A material that has a melting point that is equal to or less than 68°F (20°C) and a boiling point that is greater than 68°F (20°C) at 14.7 pounds per square inch absolute (psia) (101 kPa).
- Piping — IRC 2009: Where used in this code, “piping” refers to either pipe or tubing, or both.
Ground Source Heat Pump Loop System: 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 | Hydronic Piping (IMC 2009) | |
| Re-check the requirement that uses it | Hvdronic Piping (IRC 2009) | |
| Re-check the requirement that uses it | Definitions (IMC 2009) | |
| Confirm the dependent definition | Heat Transfer Liquid | |
| Confirm the dependent definition | Heat Pump | |
| Confirm the dependent definition | Liquid | |
| 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
- Heat Transfer Liquid: Building Code Definition
- Heat Pump: Building Code Definition
- Piping: Building Code Definition
- Liquid: 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 ground source heat pump loop system?
The International Mechanical Code (IMC) 2009 defines it in Definitions as: “Piping buried in horizontal or vertical excavations or placed in a body of water for the purpose of transporting heat transfer liquid to and from a heat pump. Included in this definition are closed loop systems in which the liquid is recirculated and open loop systems in which the liquid is drawn from a well or other source.” 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 ground source heat pump loop system?
In this corpus the term is used across 3 chapters, led by Hydronic Piping 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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