# Duration OF Load: Building Code Definition > How the IBC 2009 define duration of load, where the wording differs, and which chapters depend on the term. - Canonical: https://harth.build/resources/glossary/duration-of-load/ - 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 Structural Design (model text, not a jurisdiction's adopted text) | | Chapters using the term | 3 (counted across the codes hosted here) | | Wording identical across codes | Single code (compare before citing one code's wording under another) | ## Direct answer Duration OF load is a defined term in the International Building Code (IBC) 2009, in Structural Design. The code's own words are: “The period of continuous application of a given load, or the aggregate of periods of intermittent applications of the same load.” 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 3 chapters of this corpus, most often in Structural Tests and Special Inspections (IBC 2009), Definitions (IBC 2009), Structural Design (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? **Duration OF Load** — IBC 2009, Structural Design: > The period of continuous application of a given load, or the aggregate of periods of intermittent applications of the same load. ![Labeled code-term definition diagram: Duration OF Load: Building Code Definition](https://efwwel0vyt9vy5so.public.blob.vercel-storage.com/images/glossary/duration-of-load/diagram-1344.webp) *How the IBC 2009 define duration of load, where the wording differs, and which chapters depend on the term.* ## What must be verified before using this guidance? **Duration OF Load** is defined once in this corpus, in the [Structural Design](https://harth.build/resources/building-codes/us-states/maryland/ibc-2009/structural-design.md) chapter of the International Building Code (IBC) 2009: > The period of continuous application of a given load, or the aggregate of periods of intermittent applications of the same load. ## Where duration of load 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 | | --- | --- | --- | | [Structural Tests and Special Inspections](https://harth.build/resources/building-codes/us-states/maryland/ibc-2009/structural-tests-and-special-inspections.md) | IBC 2009 | 4 | | [Definitions](https://harth.build/resources/building-codes/us-states/maryland/ibc-2009/definitions.md) | IBC 2009 | 1 | | [Structural Design](https://harth.build/resources/building-codes/us-states/maryland/ibc-2009/structural-design.md) | IBC 2009 | 1 | ## The terms duration OF load 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 duration OF load covers: - **[Aggregate](https://harth.build/resources/glossary/aggregate.md)** — IBC 2009: In roofing, crushed stone, crushed slag or water-worn gravel used for surfacing for roof coverings. ## Duration OF Load: 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 | Structural Design | | | Re-check the requirement that uses it | Structural Tests and Special Inspections (IBC 2009) | | | Re-check the requirement that uses it | Definitions (IBC 2009) | | | Re-check the requirement that uses it | Structural Design (IBC 2009) | | | Confirm the dependent definition | Aggregate | | | 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) - [Aggregate: Building Code Definition](https://harth.build/resources/glossary/aggregate.md) - [Design Flood Elevation: Building Code Definition](https://harth.build/resources/glossary/design-flood-elevation.md) - [Loads: Building Code Definition](https://harth.build/resources/glossary/loads.md) - [Seismic Design Category: Building Code Definition](https://harth.build/resources/glossary/seismic-design-category.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 duration of load? The International Building Code (IBC) 2009 defines it in Structural Design as: “The period of continuous application of a given load, or the aggregate of periods of intermittent applications of the same load.” 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 duration of load? In this corpus the term is used across 3 chapters, led by Structural Tests and Special Inspections 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 load requirements for an IBC handrail? Handrail is a separate defined term. The IBC 2009 defines it as: “A horizontal or sloping rail intended for grasping by the hand for guidance or support.” That is not the same as duration OF load, which the IBC 2009 defines as “The period of continuous application of a given load, or the aggregate of periods of intermittent applications of the same load.” — read both before applying either, and confirm the wording in the edition your jurisdiction has adopted. ### What does IBC mean in building codes? Building is a separate defined term. The IBC 2009 defines it as: “Any structure used or intended for supporting or sheltering any use or occupancy.” That is not the same as duration OF load, which the IBC 2009 defines as “The period of continuous application of a given load, or the aggregate of periods of intermittent applications of the same load.” — read both before applying either, and confirm the wording in the edition your jurisdiction has adopted. --- - Continue in Harth (open this topic in the Harth agent): https://app.harth.build/agent?context=%2Fresources%2Fglossary%2Fduration-of-load%2F - View this page in a browser: https://harth.build/resources/glossary/duration-of-load/ - All resources for agents: https://harth.build/llms.txt