Building Code Glossary
Quantity-distance (Q-D): Building Code Definition
How the IFC 2009 define quantity-distance (q-d), 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
Quantity-distance (q-d) is a defined term in the International Fire Code (IFC) 2009, in Explosives and Fireworks. The code's own words are: “The quantity of explosive material and separation distance relationships providing protection. These relationships are based on levels of risk considered acceptable for the stipulated exposures and are tabulated in the appropriate Q-D tables. The separation distances specified afford less than absolute safety:” No other I-Code in this corpus defines it, so the IFC 2009 definition is the one to work from. The term is used in 2 chapters of this corpus, most often in Explosives and Fireworks (IFC 2009), Definitions (IFC 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?
Quantity-distance (Q-D) — IFC 2009, Explosives and Fireworks:
The quantity of explosive material and separation distance relationships providing protection. These relationships are based on levels of risk considered acceptable for the stipulated exposures and are tabulated in the appropriate Q-D tables. The separation distances specified afford less than absolute safety:
What must be verified before using this guidance?
Quantity-distance (Q-D) is defined once in this corpus, in the Explosives and Fireworks chapter of the International Fire Code (IFC) 2009:
The quantity of explosive material and separation distance relationships providing protection. These relationships are based on levels of risk considered acceptable for the stipulated exposures and are tabulated in the appropriate Q-D tables. The separation distances specified afford less than absolute safety:
Where quantity-distance (q-d) 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 |
|---|---|---|
| Explosives and Fireworks | IFC 2009 | 3 |
| Definitions | IFC 2009 | 1 |
The terms quantity-distance (q-d) is built out of
The definition above leans on 2 other defined terms. Each carries its own code definition, and a local amendment to any of them changes what quantity-distance (q-d) covers:
- Explosive Material — IFC 2009: The term "explosive" material means explosives, blasting agents and detonators.
- Explosive — IBC 2009: A chemical compound, mixture or device, the primary or common purpose of which is to function by explosion.
Quantity-distance (Q-D): 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 IFC | Explosives and Fireworks | |
| Re-check the requirement that uses it | Explosives and Fireworks (IFC 2009) | |
| Re-check the requirement that uses it | Definitions (IFC 2009) | |
| Confirm the dependent definition | Explosive Material | |
| Confirm the dependent definition | Explosive | |
| 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
- Explosive Material: Building Code Definition
- Explosive: 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 quantity-distance (q-d)?
The International Fire Code (IFC) 2009 defines it in Explosives and Fireworks as: “The quantity of explosive material and separation distance relationships providing protection. These relationships are based on levels of risk considered acceptable for the stipulated exposures and are tabulated in the appropriate Q-D tables. The separation distances specified afford less than absolute safety:” 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 quantity-distance (q-d)?
In this corpus the term is used across 2 chapters, led by Explosives and Fireworks in the IFC 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 abbreviation for a building?
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 quantity-distance (q-d), which the IFC 2009 defines as “The quantity of explosive material and separation distance relationships providing protection. These relationships are based on levels of risk considered acceptable for the stipulated exposures and are tabulated in the appropriate Q-D tables. The separation distances specified afford less than …” — read both before applying either, and confirm the wording in the edition your jurisdiction has adopted.
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