Building Code Glossary
Designated Seismic System: Building Code Definition
How the IBC 2009 define designated seismic system, 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
Designated seismic system is a defined term in the International Building Code (IBC) 2009, in Structural Tests and Special Inspections. The code's own words are: “Those architectural, electrical and mechanical systems and their components that require design in accordance with Chapter 13 of ASCE 7 and for which the component importance factor, Ip, is greater than 1 in accordance with Section 13.1.3 of ASCE 7.” 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 2 chapters of this corpus, most often in Structural Tests and Special Inspections (IBC 2009), Definitions (IBC 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?
Designated Seismic System — IBC 2009, Structural Tests and Special Inspections:
Those architectural, electrical and mechanical systems and their components that require design in accordance with Chapter 13 of ASCE 7 and for which the component importance factor, Ip, is greater than 1 in accordance with Section 13.1.3 of ASCE 7.
What must be verified before using this guidance?
Designated Seismic System is defined once in this corpus, in the Structural Tests and Special Inspections chapter of the International Building Code (IBC) 2009:
Those architectural, electrical and mechanical systems and their components that require design in accordance with Chapter 13 of ASCE 7 and for which the component importance factor, Ip, is greater than 1 in accordance with Section 13.1.3 of ASCE 7.
Where designated seismic system is used in the code
The term appears in 2 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 | IBC 2009 | 15 |
| Definitions | IBC 2009 | 1 |
The term in use
How the code actually writes about designated seismic system, quoted from the 2009 text hosted here:
Each contractor responsible for the construction of a main wind-or seismic-force-resisting system, designated seismic system or a wind- or seismic-resisting component listed in the statement of special inspections shall submit a written statement of responsibility to the bUilding official and the owner prior to the commencement of work on the system or component.
The terms designated seismic system 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 designated seismic system covers:
- Mechanical Systems — IBC 2009: For the purposes of determining seismic loads in ASCE 7, mechanical systems shall include plumbing systems as specified therein.
Designated Seismic System: 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 IBC | Structural Tests and Special Inspections | |
| Re-check the requirement that uses it | Structural Tests and Special Inspections (IBC 2009) | |
| Re-check the requirement that uses it | Definitions (IBC 2009) | |
| Confirm the dependent definition | Mechanical Systems | |
| 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
- Mechanical Systems: Building Code Definition
- Approved Agency: Building Code Definition
- Special Inspection: Building Code Definition
- Sprayed Fire-resistant Materials: 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 designated seismic system?
The International Building Code (IBC) 2009 defines it in Structural Tests and Special Inspections as: “Those architectural, electrical and mechanical systems and their components that require design in accordance with Chapter 13 of ASCE 7 and for which the component importance factor, Ip, is greater than 1 in accordance with Section 13.1.3 of ASCE 7.” 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 designated seismic system?
In this corpus the term is used across 2 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 seismic 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 designated seismic system, which the IBC 2009 defines as “Those architectural, electrical and mechanical systems and their components that require design in accordance with Chapter 13 of ASCE 7 and for which the component importance factor, Ip, is greater than 1 in accordance with Section 13.1.3 of ASCE 7.” — read both before applying either, and confirm the wording in the edition your jurisdiction has adopted.
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