Building Code Glossary
Pressure-relief Valve: Building Code Definition
How the IRC 2009 define pressure-relief 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
Pressure-relief valve is a defined term in the International Residential Code (IRC) 2009, in Definitions. The code's own words are: “A pressure-actuated valve held closed by a spring or other means and designed to automatically relieve pressure at the pressure at which it is set.” No other I-Code in this corpus defines it, so the IRC 2009 definition is the one to work from. The term is used in 5 chapters of this corpus, most often in Water Heaters (IRC 2009), Boilers and Water Heaters (IRC 2009), Definitions (IRC 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, Harth founder and architectural technology specialist · Published 2026-09-07 · Updated 2026-09-07.
What does this term mean?
Pressure-relief Valve — IRC 2009, Definitions:
A pressure-actuated valve held closed by a spring or other means and designed to automatically relieve pressure at the pressure at which it is set.
What must be verified before using this guidance?
Pressure-relief Valve is defined once in this corpus, in the Definitions chapter of the International Residential Code (IRC) 2009:
A pressure-actuated valve held closed by a spring or other means and designed to automatically relieve pressure at the pressure at which it is set.
Where pressure-relief valve is used in the code
The term appears in 5 chapters of the 2009 I-Codes hosted here. The chapters that lean on it hardest are the ones to read next.
| Chapter | Code | Mentions |
|---|---|---|
| Water Heaters | IRC 2009 | 4 |
| Boilers and Water Heaters | IRC 2009 | 3 |
| Definitions | IRC 2009 | 2 |
| Solar Systems | IRC 2009 | 2 |
| Special Piping and Storage Systems | IRC 2009 | 1 |
The term in use
How the code actually writes about pressure-relief valve, quoted from the 2009 text hosted here:
Where the shutoffvalve is installed in the discharge line of an oil pump, a pressure-relief valve shall be incorporated to bypass or return surplus oil.
Pressure-relief Valve compared with Pressure Relief Valve
These two are the closest pair in the 2009 I-Codes: about 61 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 | |
|---|---|
| Pressure-relief Valve (IRC 2009) | set |
| Pressure Relief Valve (IMC 2009) | excess, device, s, setting |
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 pressure-relief valve and pressure relief valve.
The terms pressure-relief valve 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 pressure-relief valve covers:
- 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.
Pressure-relief 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 IRC | Definitions | |
| Re-check the requirement that uses it | Water Heaters (IRC 2009) | |
| Re-check the requirement that uses it | Boilers and Water Heaters (IRC 2009) | |
| Re-check the requirement that uses it | Definitions (IRC 2009) | |
| Re-check the requirement that uses it | Solar Systems (IRC 2009) | |
| 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
- Valve: Building Code Definition
- Building: Building Code Definition
- Construction Documents: Building Code Definition
- Registered Design Professional: 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 pressure-relief valve?
The International Residential Code (IRC) 2009 defines it in Definitions as: “A pressure-actuated valve held closed by a spring or other means and designed to automatically relieve pressure at the pressure at which it is set.” 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 pressure-relief valve?
In this corpus the term is used across 5 chapters, led by Water Heaters in the IRC 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 specifications of a pressure relief valve?
Pressure Relief Valve is a separate defined term. The IMC 2009 defines it as: “A pressure-actuated valve held closed by a spring or other means and designed to relieve pressure automatically in excess of the device's setting.” That is not the same as pressure-relief valve, which the IRC 2009 defines as “A pressure-actuated valve held closed by a spring or other means and designed to automatically relieve pressure at the pressure at which it is set.” — read both before applying either, and confirm the wording in the edition your jurisdiction has adopted.
Related pages
- Pressure Drop: Building Code Definition
Pressure Drop — IRC 2009 definition: The loss in pressure due to friction or obstruction in pipes, valves, fittings, regulators and burners.
- Pressure-limiting Device: Building Code Definition
Pressure-limiting Device — IMC 2009 definition: A pressure-responsive mechanism designed to stop automatically the operation of the pressure-imposing element at a predeterm…
- Pressure Relief Device: Building Code Definition
Pressure Relief Device — IMC 2009 definition: A pressure-actuated valve or rupture member designed to relieve excessive pressure automatically.
- Pressure Relief Valve: Building Code Definition
Pressure Relief Valve — IMC 2009 definition: A pressure-actuated valve held closed by a spring or other means and designed to relieve pressure …
- Pressure Test: Building Code Definition
Pressure Test — IRC 2009 definition: An operation performed to verify the gas-tight integrity of gas piping following its installation or modification.
- Pressure Vessel: Building Code Definition
Pressure Vessel — IFC 2009 definition: A closed vessel designed to operate at pressures above 15 psig (103 kPa).