Building Code Glossary
Reduced Flow Valve: Building Code Definition
How the IFC 2009 define reduced flow valve, 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
Reduced flow valve is a defined term in the International Fire Code (IFC) 2009, in Highly Toxic and Toxic Materials. The code's own words are: “A valve equipped with a restricted flow orifice and inserted into a compressedgas cylinder, portable tank or stationary tank that is designed to reduce the maximum flow from the valve under full-flow conditions. The maximum flow rate from the valve is determined with the valve allowed to flow to atmosphere with no other piping or …” 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 Highly Toxic and Toxic Materials (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?
Reduced Flow Valve — IFC 2009, Highly Toxic and Toxic Materials:
A valve equipped with a restricted flow orifice and inserted into a compressedgas cylinder, portable tank or stationary tank that is designed to reduce the maximum flow from the valve under full-flow conditions. The maximum flow rate from the valve is determined with the valve allowed to flow to atmosphere with no other piping or fittings attached.
What must be verified before using this guidance?
Reduced Flow Valve is defined once in this corpus, in the Highly Toxic and Toxic Materials chapter of the International Fire Code (IFC) 2009:
A valve equipped with a restricted flow orifice and inserted into a compressedgas cylinder, portable tank or stationary tank that is designed to reduce the maximum flow from the valve under full-flow conditions. The maximum flow rate from the valve is determined with the valve allowed to flow to atmosphere with no other piping or fittings attached.
Where reduced flow valve 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 |
|---|---|---|
| Highly Toxic and Toxic Materials | IFC 2009 | 4 |
| Definitions | IFC 2009 | 1 |
The terms reduced flow valve 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 reduced flow valve covers:
- Cylinder — IFC 2009: A pressure vessel designed for pressures higher than 40 psia (275.6 kPa) and having a circular cross section.
- Piping — IRC 2009: Where used in this code, “piping” refers to either pipe or tubing, or both.
- Valve — IRC 2009: A device used in piping to control the gas supply to any section of a system of piping or to an appliance.
Reduced Flow Valve: 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 | Highly Toxic and Toxic Materials | |
| Re-check the requirement that uses it | Highly Toxic and Toxic Materials (IFC 2009) | |
| Re-check the requirement that uses it | Definitions (IFC 2009) | |
| Confirm the dependent definition | Cylinder | |
| Confirm the dependent definition | Piping | |
| Confirm the dependent definition | Valve | |
| 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
- Cylinder: Building Code Definition
- Piping: Building Code Definition
- Valve: 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 reduced flow valve?
The International Fire Code (IFC) 2009 defines it in Highly Toxic and Toxic Materials as: “A valve equipped with a restricted flow orifice and inserted into a compressedgas cylinder, portable tank or stationary tank that is designed to reduce the maximum flow from the valve under full-flow conditions. The maximum flow rate from the valve is determined with the valve allowed to flow to atmosphere with no other piping or fittings attached.” 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 reduced flow valve?
In this corpus the term is used across 2 chapters, led by Highly Toxic and Toxic Materials 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.
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