# Type A Unit: Building Code Definition > How the IBC 2009 define type a unit, where the wording differs, and which chapters depend on the term. - Canonical: https://harth.build/resources/glossary/type-a-unit/ - 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 | IBC 2009 (2009 editions transcribed in this corpus) | | Primary source | IBC 2009 Accessibility (model text, not a jurisdiction's adopted text) | | Chapters using the term | 6 (counted across the codes hosted here) | | Wording identical across codes | Single code (compare before citing one code's wording under another) | ## Direct answer Type A unit is a defined term in the International Building Code (IBC) 2009, in Accessibility. The code's own words are: “A dwelling unit or sleeping unit designed and constructed for accessibility in accordance with this code and the provisions for Type A units in ICC Al17.1.” No other I-Code in this corpus defines it, so the IBC 2009 definition is the one to work from. The term is used in 6 chapters of this corpus, most often in Accessibility (IBC 2009), Means of Egress (IFC 2009), Means of Egress (IBC 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? **Type A Unit** — IBC 2009, Accessibility: > A dwelling unit or sleeping unit designed and constructed for accessibility in accordance with this code and the provisions for Type A units in ICC Al17.1. ![Labeled code-term definition diagram: Type A Unit: Building Code Definition](https://efwwel0vyt9vy5so.public.blob.vercel-storage.com/images/glossary/type-a-unit/diagram-1344.webp) *How the IBC 2009 define type a unit, where the wording differs, and which chapters depend on the term.* ## What must be verified before using this guidance? **Type A Unit** is defined once in this corpus, in the [Accessibility](https://harth.build/resources/building-codes/us-states/maryland/ibc-2009/accessibility.md) chapter of the International Building Code (IBC) 2009: > A dwelling unit or sleeping unit designed and constructed for accessibility in accordance with this code and the provisions for Type A units in ICC Al17.1. ## Where type a unit is used in the code The term appears in 6 chapters of the 2009 I-Codes hosted here. The chapters that lean on it hardest are the ones to read next. | Chapter | Code | Mentions | | --- | --- | --- | | [Accessibility](https://harth.build/resources/building-codes/us-states/maryland/ibc-2009/accessibility.md) | IBC 2009 | 45 | | [Means of Egress](https://harth.build/resources/building-codes/us-states/rhode-island/ifc-2009/means-of-egress.md) | IFC 2009 | 15 | | [Means of Egress](https://harth.build/resources/building-codes/us-states/maryland/ibc-2009/means-of-egress.md) | IBC 2009 | 14 | | [Special Construction](https://harth.build/resources/building-codes/us-states/maryland/ibc-2009/special-construction.md) | IBC 2009 | 6 | | [Existing Structures](https://harth.build/resources/building-codes/us-states/maryland/ibc-2009/existing-structures.md) | IBC 2009 | 2 | | [Definitions](https://harth.build/resources/building-codes/us-states/maryland/ibc-2009/definitions.md) | IBC 2009 | 1 | ### The term in use How the code actually writes about type a unit, quoted from the 2009 text hosted here: > At least one accessible route shall connect accessible building or facility entrances with the primary entrance of each Accessible unit, Type A unit and Type B unit within the building or facility and with those exterior and interior spaces and facilities that serve the units. — [IBC 2009 §1107.4](https://harth.build/resources/building-codes/us-states/maryland/ibc-2009/accessibility.md) ## Type A Unit compared with Type B Unit These two are the closest pair in the 2009 I-Codes: about 69 per cent of their defining words are the same. The code states both and compares neither, so the difference is worth naming. | | Wording unique to it | | --- | --- | | **Type A Unit** (IBC 2009) | — no wording of its own | | [Type B Unit](https://harth.build/resources/glossary/type-b-unit.md) (IBC 2009) | b, consistent, design, construction, requirements, federal, fair, housing, act | Everything else in the two definitions is shared. If a project turns on which of the two applies, those words are the whole of the test — and a local amendment that edits one of them without editing the other moves the boundary between type A unit and type B unit. ## The terms type A unit is built out of The definition above leans on 3 other defined terms. Each carries its own code definition, and a local amendment to any of them changes what type A unit covers: - **[Dwelling Unit](https://harth.build/resources/glossary/dwelling-unit.md)** — IBC 2009: A single unit providing complete, independent living facilities for one or more persons, including permanent provisions for living, sleeping, eating, cooking and sanitation. - **[Sleeping Unit](https://harth.build/resources/glossary/sleeping-unit.md)** — IBC 2009: A room or space in which people sleep, which can also include permanent provisions for living, eating, and either sanitation or kitchen facilities but not both. - **[Dwelling](https://harth.build/resources/glossary/dwelling.md)** — IBC 2009: A building that contains one or two dwelling units used, intended or designed to be used, rented, leased, let or hired out to be occupied for living purposes. ## Type A Unit: 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 IBC | Accessibility | | | Re-check the requirement that uses it | Accessibility (IBC 2009) | | | Re-check the requirement that uses it | Means of Egress (IFC 2009) | | | Re-check the requirement that uses it | Means of Egress (IBC 2009) | | | Re-check the requirement that uses it | Special Construction (IBC 2009) | | | Confirm the dependent definition | Dwelling Unit | | | Confirm the dependent definition | Sleeping Unit | | | Confirm the dependent definition | Dwelling | | | 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) - [Sleeping Unit: Building Code Definition](https://harth.build/resources/glossary/sleeping-unit.md) - [Dwelling Unit: Building Code Definition](https://harth.build/resources/glossary/dwelling-unit.md) - [Dwelling: Building Code Definition](https://harth.build/resources/glossary/dwelling.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 type a unit? The International Building Code (IBC) 2009 defines it in Accessibility as: “A dwelling unit or sleeping unit designed and constructed for accessibility in accordance with this code and the provisions for Type A units in ICC Al17.1.” 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 type a unit? In this corpus the term is used across 6 chapters, led by Accessibility in the IBC 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 are the requirements for an ANSI Type A bathroom? Bathroom is a separate defined term. The IRC 2009 defines it as: “An area, including a basin, with one or more of the following: a toilet, a tub or a shower.” That is not the same as type A unit, which the IBC 2009 defines as “A dwelling unit or sleeping unit designed and constructed for accessibility in accordance with this code and the provisions for Type A units in ICC Al17.1.” — read both before applying either, and confirm the wording in the edition your jurisdiction has adopted. ### What are the requirements for an ANSI Type A unit? In the 2009 I-Codes hosted here it is a defined term rather than a description. The IBC 2009 states, in Accessibility: “A dwelling unit or sleeping unit designed and constructed for accessibility in accordance with this code and the provisions for Type A units in ICC Al17.1.” It is defined in IBC 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%2Ftype-a-unit%2F - View this page in a browser: https://harth.build/resources/glossary/type-a-unit/ - All resources for agents: https://harth.build/llms.txt