Building Code Glossary
Pressure Relief Device: Building Code Definition
How the IMC 2009 define pressure relief device, 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 device is a defined term in the International Mechanical Code (IMC) 2009, in Definitions. The code's own words are: “A pressure-actuated valve or rupture member designed to relieve excessive pressure automatically.” No other I-Code in this corpus defines it, so the IMC 2009 definition is the one to work from. The term is used in 11 chapters of this corpus, most often in Cryogenic Fluids (IFC 2009), Motor Fuel-dispensing Facilities and Repair Garages (IFC 2009), Compressed Gases (IFC 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 Device — IMC 2009, Definitions:
A pressure-actuated valve or rupture member designed to relieve excessive pressure automatically.
What must be verified before using this guidance?
Pressure Relief Device is defined once in this corpus, in the Definitions chapter of the International Mechanical Code (IMC) 2009:
A pressure-actuated valve or rupture member designed to relieve excessive pressure automatically.
Where pressure relief device is used in the code
The term appears in 11 chapters of the 2009 I-Codes hosted here. The chapters that lean on it hardest are the ones to read next.
| Chapter | Code | Mentions |
|---|---|---|
| Cryogenic Fluids | IFC 2009 | 37 |
| Motor Fuel-dispensing Facilities and Repair Garages | IFC 2009 | 30 |
| Compressed Gases | IFC 2009 | 14 |
| Highly Toxic and Toxic Materials | IFC 2009 | 13 |
| Flammable Gases and Flammable Cryogenic Fluids | IFC 2009 | 12 |
| Building Services and Systems | IFC 2009 | 9 |
| Refrigeration | IMC 2009 | 6 |
| Hazardous Materials-general Provisions | IFC 2009 | 3 |
| Flammable and Combustible Liquids | IFC 2009 | 2 |
| Special Detailed Requirements Based on Use and Occupancy | IBC 2009 | 1 |
| Definitions | IMC 2009 | 1 |
The term in use
How the code actually writes about pressure relief device, quoted from the 2009 text hosted here:
Heat exchangers, vaporizers, insulation casings surrounding containers, vessels and coaxial piping systems in which liquefied cryogenic fluids could be trapped because of leakage from the primary container shall be provided with a pressure relief device.
The discharge pipe from the pressure relief device shall distribute ammonia in the bottom of the tank, but no lower than 33 feet (10 058 mm) below the maximum liquid level.
Joints and all refrigerant-containing parts of a refrigerating system located in an air duct of an air-conditioning system carrying conditioned air to and from human-occupied space shall be constructed to withstand, without leakage, a pressure of 150 percent of the higher of the design pressure or pressure relief device setting.
The terms pressure relief device 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 device 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 Device: 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 IMC | Definitions | |
| Re-check the requirement that uses it | Cryogenic Fluids (IFC 2009) | |
| Re-check the requirement that uses it | Motor Fuel-dispensing Facilities and Repair Garages (IFC 2009) | |
| Re-check the requirement that uses it | Compressed Gases (IFC 2009) | |
| Re-check the requirement that uses it | Highly Toxic and Toxic Materials (IFC 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 device?
The International Mechanical Code (IMC) 2009 defines it in Definitions as: “A pressure-actuated valve or rupture member designed to relieve excessive pressure automatically.” 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 device?
In this corpus the term is used across 11 chapters, led by Cryogenic Fluids 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 a pressure relief device?
In the 2009 I-Codes hosted here it is a defined term rather than a description. The IMC 2009 states, in Definitions: “A pressure-actuated valve or rupture member designed to relieve excessive pressure automatically.” It is defined in IMC 2009. Because it is a defined term, whatever the adopted edition says it means is what every section using it means — so check Chapter 2 of that edition and any local amendment before relying on this wording.
What is the code for a pressure relief valve on a water heater?
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 device, which the IMC 2009 defines as “A pressure-actuated valve or rupture member designed to relieve excessive pressure automatically.” — read both before applying either, and confirm the wording in the edition your jurisdiction has adopted.
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