Building Code Glossary
Environmental Air: Building Code Definition
How the IMC 2009 define environmental air, 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
Environmental air is a defined term in the International Mechanical Code (IMC) 2009, in Definitions. The code's own words are: “Air that is conveyed to or from occupied areas through ducts which are not part of the heating or air-conditioning system, such as ventilation for human usage, domestic kitchen range exhaust, bathroom exhaust and domestic clothes dryer exhaust.” 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 Exhaust Systems (IMC 2009), Class 2 Remote-control, Signaling and Power-limited Circuits (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?
Environmental Air — IMC 2009, Definitions:
Air that is conveyed to or from occupied areas through ducts which are not part of the heating or air-conditioning system, such as ventilation for human usage, domestic kitchen range exhaust, bathroom exhaust and domestic clothes dryer exhaust.
What must be verified before using this guidance?
Environmental Air is defined once in this corpus, in the Definitions chapter of the International Mechanical Code (IMC) 2009:
Air that is conveyed to or from occupied areas through ducts which are not part of the heating or air-conditioning system, such as ventilation for human usage, domestic kitchen range exhaust, bathroom exhaust and domestic clothes dryer exhaust.
Where environmental air 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 |
|---|---|---|
| Exhaust Systems | IMC 2009 | 2 |
| Class 2 Remote-control, Signaling and Power-limited Circuits | IRC 2009 | 2 |
| Definitions | IMC 2009 | 1 |
The term in use
How the code actually writes about environmental air, quoted from the 2009 text hosted here:
Cables installed in ducts, plenums and other spaces used to convey environmental air shall be Type CL2P cables listed as being suitable for the use and listed as having adequate fire-resistant and low smoke-producing characteristics.
The terms environmental air 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 environmental air covers:
- Air-conditioning System — IRC 2009: A system that consists of heat exchangers, blowers, filters, supply, exhaust and return-air systems, and shall include any apparatus installed in connection therewith.
- Clothes Dryer — IRC 2009: An appliance used to dry wet laundry by means of heated air.
- Ventilation — IBC 2009: The natural or mechanical process of supplying conditioned or unconditioned air to, or removing such air from, any space.
- Bathroom — IRC 2009: An area, including a basin, with one or more of the following: a toilet, a tub or a shower.
- Kitchen — IRC 2009: Kitchen shall mean an area used, or designated to be used, for the preparation of food.
Environmental Air: 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 | Exhaust Systems (IMC 2009) | |
| Re-check the requirement that uses it | Class 2 Remote-control, Signaling and Power-limited Circuits (IRC 2009) | |
| Re-check the requirement that uses it | Definitions (IMC 2009) | |
| Confirm the dependent definition | Air-conditioning System | |
| Confirm the dependent definition | Clothes Dryer | |
| Confirm the dependent definition | Ventilation | |
| 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
- Air-conditioning System: Building Code Definition
- Clothes Dryer: Building Code Definition
- Ventilation: Building Code Definition
- Bathroom: 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 environmental air?
The International Mechanical Code (IMC) 2009 defines it in Definitions as: “Air that is conveyed to or from occupied areas through ducts which are not part of the heating or air-conditioning system, such as ventilation for human usage, domestic kitchen range exhaust, bathroom exhaust and domestic clothes dryer exhaust.” 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 environmental air?
In this corpus the term is used across 3 chapters, led by Exhaust Systems 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 the definition of environmental air?
In the 2009 I-Codes hosted here it is a defined term rather than a description. The IMC 2009 states, in Definitions: “Air that is conveyed to or from occupied areas through ducts which are not part of the heating or air-conditioning system, such as ventilation for human usage, domestic kitchen range exhaust, bathroom exhaust and domestic clothes dryer exhaust.” 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.
What are the ventilation requirements according to the International Mechanical Code?
Ventilation is a separate defined term. The IBC 2009 defines it as: “The natural or mechanical process of supplying conditioned or unconditioned air to, or removing such air from, any space.” That is not the same as environmental air, which the IMC 2009 defines as “Air that is conveyed to or from occupied areas through ducts which are not part of the heating or air-conditioning system, such as ventilation for human usage, domestic kitchen range exhaust, bathroom exhaust and domestic clothes dryer exhaust.” — read both before applying either, and confirm the wording in the edition your jurisdiction has adopted.
What does "ventilation air" mean?
Ventilation Air is a separate defined term. The IMC 2009 defines it as: “That portion of supply air that comes from the outside (outdoors), plus any recirculated air that has been treated to maintain the desired quality of air within a designated space.” That is not the same as environmental air, which the IMC 2009 defines as “Air that is conveyed to or from occupied areas through ducts which are not part of the heating or air-conditioning system, such as ventilation for human usage, domestic kitchen range exhaust, bathroom exhaust and domestic clothes dryer exhaust.” — read both before applying either, and confirm the wording in the edition your jurisdiction has adopted.
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