Updated 2026-09-07

Building Code Glossary

Fusible Plug: Building Code Definition

How the IMC 2009 define fusible plug, 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.

Add to Harth agentView as markdown

Direct answer

Fusible plug is a defined term in the International Mechanical Code (IMC) 2009, in Definitions. The code's own words are: “A device arranged to relieve pressure by operation of a fusible member at a predetermined temperature.” 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. 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, Harth founder and architectural technology specialist · Published 2026-09-07 · Updated 2026-09-07.

What does this term mean?

Fusible Plug — IMC 2009, Definitions:

A device arranged to relieve pressure by operation of a fusible member at a predetermined temperature.

Labeled code-term definition diagram: Fusible Plug: Building Code Definition — How the IMC 2009 define fusible plug, where the wording differs, and which chapters depend on the term.

What must be verified before using this guidance?

Fusible Plug is defined once in this corpus, in the Definitions chapter of the International Mechanical Code (IMC) 2009:

A device arranged to relieve pressure by operation of a fusible member at a predetermined temperature.

Where fusible plug 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	3
Definitions	IMC 2009	1
Refrigeration	IMC 2009	1

The term in use

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

Discharge piping and devices connected to the discharge side of a fusible plug or rupture member shall have provisions to prevent plugging the pipe in the event of the fusible plug or rupture member functions.

— IFC 2009, Building Services and Systems

The terms fusible plug 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 fusible plug covers:

Device — IRC 2009: Aunit of an electrical system that carries or controls electrical energy as it principal function.

Fusible Plug: 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	Device
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.

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 fusible plug?

The International Mechanical Code (IMC) 2009 defines it in Definitions as: “A device arranged to relieve pressure by operation of a fusible member at a predetermined temperature.” 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 fusible plug?

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 fusible plug?

In the 2009 I-Codes hosted here it is a defined term rather than a description. The IMC 2009 states, in Definitions: “A device arranged to relieve pressure by operation of a fusible member at a predetermined temperature.” 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.

Related pages

The AI-powered workspacefor architects.

Get started for free Continue in Harth