# Joint, Welded: Building Code Definition > How the IMC 2009 define joint, welded, where the wording differs, and which chapters depend on the term. - Canonical: https://harth.build/resources/glossary/joint-welded/ - 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 | 4 (counted across the codes hosted here) | | Wording identical across codes | Single code (compare before citing one code's wording under another) | ## Direct answer Joint, welded is a defined term in the International Mechanical Code (IMC) 2009, in Definitions. The code's own words are: “A gas-tight joint obtained by the joining of metal parts in molten state.” 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 4 chapters of this corpus, most often in Fuel Oil Piping and Storage (IMC 2009), Hydronic Piping (IMC 2009), Fuel Gas (IRC 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? **Joint, Welded** — IMC 2009, Definitions: > A gas-tight joint obtained by the joining of metal parts in molten state. ![Labeled code-term definition diagram: Joint, Welded: Building Code Definition](https://efwwel0vyt9vy5so.public.blob.vercel-storage.com/images/glossary/joint-welded/diagram-1344.webp) *How the IMC 2009 define joint, welded, where the wording differs, and which chapters depend on the term.* ## What must be verified before using this guidance? **Joint, Welded** 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: > A gas-tight joint obtained by the joining of metal parts in molten state. ## Where joint, welded is used in the code The term appears in 4 chapters of the 2009 I-Codes hosted here. The chapters that lean on it hardest are the ones to read next. | Chapter | Code | Mentions | | --- | --- | --- | | [Fuel Oil Piping and Storage](https://harth.build/resources/building-codes/us-states/new-hampshire/imc-2009/fuel-oil-piping-and-storage.md) | IMC 2009 | 7 | | [Hydronic Piping](https://harth.build/resources/building-codes/us-states/new-hampshire/imc-2009/hydronic-piping.md) | IMC 2009 | 7 | | [Fuel Gas](https://harth.build/resources/building-codes/us-states/maryland/irc-2009/fuel-gas.md) | IRC 2009 | 2 | | [Definitions](https://harth.build/resources/building-codes/us-states/new-hampshire/imc-2009/definitions.md) | IMC 2009 | 1 | ## The terms joint, welded 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 joint, welded covers: - **[Joint](https://harth.build/resources/glossary/joint.md)** — IBC 2009: The linear opening in or between adjacent fire-resistance-rated assemblies that is designed to allow independent movement of the building in any plane caused by thermal, seismic, wind or any other loading. ## Joint, Welded: 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 | Fuel Oil Piping and Storage (IMC 2009) | | | Re-check the requirement that uses it | Hydronic Piping (IMC 2009) | | | Re-check the requirement that uses it | Fuel Gas (IRC 2009) | | | Re-check the requirement that uses it | Definitions (IMC 2009) | | | Confirm the dependent definition | Joint | | | 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) - [Joint: Building Code Definition](https://harth.build/resources/glossary/joint.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 joint, welded? The International Mechanical Code (IMC) 2009 defines it in Definitions as: “A gas-tight joint obtained by the joining of metal parts in molten state.” 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 joint, welded? In this corpus the term is used across 4 chapters, led by Fuel Oil Piping and Storage 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 a welded joint? In the 2009 I-Codes hosted here it is a defined term rather than a description. The IMC 2009 states, in Definitions: “A gas-tight joint obtained by the joining of metal parts in molten state.” 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. --- - Continue in Harth (open this topic in the Harth agent): https://app.harth.build/agent?context=%2Fresources%2Fglossary%2Fjoint-welded%2F - View this page in a browser: https://harth.build/resources/glossary/joint-welded/ - All resources for agents: https://harth.build/llms.txt