Updated 2026-09-07

Building Code Glossary

Building Trap: Building Code Definition

How the IPC 2009 define building trap, where the wording differs, and which chapters depend on the term.

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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.

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Direct answer

Building trap is a defined term in the International Plumbing Code (IPC) 2009, in Definitions. The code's own words are: “A device, fitting or assembly of fittings installed in the building drain to prevent circulation of air between the drainage system of the building and the building sewer.” No other I-Code in this corpus defines it, so the IPC 2009 definition is the one to work from. The term is used in 3 chapters of this corpus, most often in Definitions (IPC 2009), Traps, Interceptors and Separators (IPC 2009), Traps (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, Harth founder and architectural technology specialist · Published 2026-09-07 · Updated 2026-09-07.

What does this term mean?

Building Trap — IPC 2009, Definitions:

A device, fitting or assembly of fittings installed in the building drain to prevent circulation of air between the drainage system of the building and the building sewer.

Labeled code-term definition diagram: Building Trap: Building Code Definition — How the IPC 2009 define building trap, where the wording differs, and which chapters depend on the term.

What must be verified before using this guidance?

Building Trap is defined once in this corpus, in the Definitions chapter of the International Plumbing Code (IPC) 2009:

A device, fitting or assembly of fittings installed in the building drain to prevent circulation of air between the drainage system of the building and the building sewer.

Where building trap 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
Definitions	IPC 2009	2
Traps, Interceptors and Separators	IPC 2009	2
Traps	IRC 2009	2

The terms building trap is built out of

The definition above leans on 5 other defined terms. Each carries its own code definition, and a local amendment to any of them changes what building trap covers:

Drainage System — IPC 2009: Piping within a public or private premise that conveys sewage, rainwater or other liquid wastes to a point of disposal.
Building Drain — IRC 2009: The lowest piping that collects the discharge from all other drainage piping inside the house and extends 30 inches (762 mm) in developed length of pipe, beyond the exterior walls and conveys the drainage to the building sewer.
Building Sewer — IRC 2009: That part of the drainage system that extends from the end of the building drain and conveys its discharge to a public sewer, private sewer, individual sewage-diSposal system or other point of disposal.
Building — IBC 2009: Any structure used or intended for supporting or sheltering any use or occupancy.
Fitting — IRC 2009: An accessory such as a locknut, bushing or other part of a wiring system that is intended primarily to perform a mechanical rather than an electrical function.

Building Trap: 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 IPC	Definitions
Re-check the requirement that uses it	Definitions (IPC 2009)
Re-check the requirement that uses it	Traps, Interceptors and Separators (IPC 2009)
Re-check the requirement that uses it	Traps (IRC 2009)
Confirm the dependent definition	Drainage System
Confirm the dependent definition	Building Drain
Confirm the dependent definition	Building Sewer
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 building trap?

The International Plumbing Code (IPC) 2009 defines it in Definitions as: “A device, fitting or assembly of fittings installed in the building drain to prevent circulation of air between the drainage system of the building and the building sewer.” 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 building trap?

In this corpus the term is used across 3 chapters, led by Definitions in the IPC 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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