When a fire breaks out, every second counts — both for first responders to arrive and for building occupants to safely evacuate the building.
Fire resistance ratings play a critical role by indicating how long specific building components and assemblies can withstand fire, helping to buy valuable time in an emergency situation.
When it comes to fire resistance testing, there are a few specific standards, such as ASTM E119 and UL 263, that play a critical role in ensuring that walls, floors, ceilings, beams, and other structural elements can withstand intense fire exposure for a designated period of time.
Understanding how different assemblies perform under fire conditions not only helps meet increasingly rigorous code requirements but, more importantly, supports occupant safety when it matters most.
In this blog, we’ll break down the key difference between ASTM E119 and UL 263 to help you decide which test standard may be the right fit for your assembly or building component.
What Is ASTM E119?
ASTM E119 is a standard test method used to evaluate the fire resistance of building construction and materials. Developed and maintained by ASTM International's E05 Committee on Fire Standards, this fire test is used to determine how long building assemblies and structural units can resist fire and maintain their structural integrity.
The test specimen is monitored for flame and hot gas penetration, temperature rise on the unexposed side, structural stability, and the integrity of fire barriers. The test will also note how long the materials resisted the fire before the first critical point of failure was observed.
What Is UL 263?
Similarly, UL Solutions’ UL 263 sets requirements for the fire testing of assemblies and structural units of buildings and is maintained through the UL Standards & Engagement Consensus Process, which brings together input from a diverse range of industry stakeholders.
Like ASTM E119, UL 263 can be applied to both load-bearing and non-load-bearing assemblies and structural units of buildings. The test evaluates how long an assembly can withstand fire exposure while maintaining structural integrity.
Similarities Between ASTM E119 and UL 263
Despite having been developed by different organizations, ASTM E119 and UL 263 share quite a few similarities:
- Scope of the Standard: Both standards test the fire resistance of walls, floors, ceilings, columns, beams, and other structural units of buildings.
- Testing Conditions: Both require exposure of the test specimen to controlled fire conditions following the same time-temperature curve.
- Performance Monitoring: Both measure structural integrity, fire penetration, and temperature rise during testing.
- Regulatory Acceptance: Both are widely recognized by building codes, regulatory authorities, and insurance bodies.
Testing for either standard typically utilizes a full-scale vertical furnace, a full-scale horizontal furnace, a pilot-scale furnace, or a column furnace. The test assembly or structural unit is monitored anywhere from one hour to several hours, based on the fire rating that is being targeted.
Both ASTM E119 and UL 263 aim to maintain strong alignment to ensure that fire resistance testing standards are carefully observed, regardless of which standard is selected. Because of these commonalities, you can often qualify materials under both standards with minimal adjustments to the testing process.
Understanding the Main Difference: Pressure Measurement Requirement
Both ASTM E119 and UL 263 are gold standards for fire resistance testing because they have been developed through rigorous, consensus-driven processes, and they share more similarities than differences.
The key distinction between these standards is the recording and reporting of furnace pressure, which is mandatory for full compliance with UL 263, but is not required for ASTM E119. Furnace pressure is considered a non-critical variable in ASTM E119, whereas UL 263 enforces quantitative control over it, including how and where to measure furnace pressure.
While ASTM E119 doesn’t require furnace pressure reporting like UL 263 does, some organizations may still decide to gather this information for broader certification or informational purposes.
Importance of Fire Resistance Testing Flexibility for Dual Compliance
One of the benefits of working with an accredited fire testing lab like NGC Testing Services is the ability to plan for dual compliance. During an ASTM E119 fire test, you can request additional data, such as furnace pressure, to ensure results may also satisfy UL 263 requirements if needed.
This flexibility is especially valuable when navigating building codes. The International Building Code (IBC), adopted by most U.S. jurisdictions for commercial buildings, typically lists ASTM E119 and UL 263 as equivalent options for meeting fire resistance requirements.
However, which version of the code is enforced can vary based on a state or municipality’s rate of adoption. Some states, like California and Florida, modify the IBC to create their own versions, and certain local jurisdictions — such as those around Chicago — may strongly prefer one test standard over the other.
Having the ability to test to either or both standards gives manufacturers and design teams greater flexibility to meet code requirements based on the specific needs of the project location.
It’s important to note that labs do not modify the standards themselves to be flexible. Instead, they strictly follow official procedures outlined in ASTM E119 and UL 263 while strategically developing a test plan to support multiple compliance outcomes.
If you're planning a project that calls for any variation of ASTM E119 or UL 263 compliance, engaging with an accredited testing facility early can save time, reduce costs, and help ensure a smooth path to code approval.
NGC Testing Services: Your Fire Resistance Testing Partner
Whether you need ASTM E119 fire rating documentation, UL 263 standard certification and compliance, or a test plan that captures both, NGC Testing Services is fully equipped and accredited to handle it all, ensuring your materials and assemblies meet all the necessary fire performance and safety benchmarks.
Have questions about your next fire resistance project? Contact NGC Testing Services today to discuss your upcoming testing.