UL-Listed O-Rings

Summary

• Global O-Ring offers UL-listed o-rings certified under UL 157, ensuring performance, safety, and compliance for demanding sealing applications across multiple industries.
• UL 157 certification validates o-ring compounds through rigorous testing for temperature, fuel resistance, ozone exposure, and mechanical properties to ensure long-term reliability in critical environments.
• Our UL-listed o-ring offering includes a wide range of materials, each approved for specific end-use codes, with data sheets and technical support readily available.

Introduction

Global O-Ring and Seal is proud to announce the launch of our UL-listed o-ring product line. These o-rings have been rigorously tested and certified under UL 157, ensuring compliance with strict safety and performance standards.

UL certification is an important benchmark for sealing components used in regulated or safety-critical environments. It confirms that the materials have passed third-party testing for performance under fuel, chemical, and environmental exposure, giving engineers and manufacturers confidence in their sealing solutions.

What Are UL-Listed O-Rings?

Underwriters Laboratories and UL 157 Overview

Underwriters Laboratories (UL) is a globally recognized, independent safety certification organization that develops standards and conducts rigorous testing to evaluate the safety, performance, and reliability of products. UL certification is trusted across industries as a mark of compliance with strict technical and safety requirements.

For elastomeric sealing components, UL 157 is a key standard. It outlines the physical property requirements and testing protocols necessary to verify a compound’s suitability for specific end-use conditions, such as exposure to fuels, refrigerants, detergents, or ozone. These tests simulate real-world environmental stressors, ensuring that o-rings retain their sealing integrity in demanding applications.

Obtaining UL 157 certification demonstrates that a seal has been validated through third-party testing to meet defined performance criteria. This level of assurance is especially important in safety-critical systems, where seal failure could result in hazardous leaks, equipment damage, or regulatory noncompliance.

UL 157 Testing Criteria

To receive UL 157 certification, elastomeric o-rings must pass a series of material property tests designed to evaluate performance under stress, aging, and environmental exposure. These tests verify the seal’s ability to maintain integrity in a range of real-world conditions.

Key properties tested under UL 157 include:

• Tensile Strength: Measures how much force the material can withstand before breaking.
• Elongation: Assesses the material’s flexibility and ability to stretch without tearing.
• Compression Set: Evaluates how well the material returns to its original shape after prolonged compression.
• Tensile Set: Indicates permanent deformation after the material has been stretched.
• Temperature Range: Verifies sealing performance across high and low temperature extremes.
• Chemical and Fuel Resistance: Confirms compatibility with fuels, oils, solvents, and other chemicals.
• Ozone Compatibility: Tests the material’s resistance to cracking or degradation from ozone exposure.

These performance benchmarks help ensure certified o-rings remain reliable in harsh or regulated environments.

Understanding End-Use Application Codes

As part of UL 157 certification, each o-ring material is approved for specific end-use application codes, labeled with letters A through R. These codes represent categories of substances or environmental conditions that the material has been tested and certified to withstand.

For customers, these codes serve as a critical reference point when selecting seals for regulated or safety-sensitive applications. Choosing an o-ring certified for the appropriate end-use helps:

• Ensure regulatory compliance
• Confirm material suitability for the intended environment
• Reduce risk of failure, damage, or liability

Below is a reference chart for UL 157 end-use codes:

Code	End-Use Environment	Code	End-Use Environment
A	Extinguishing agents*	J	Liquefied petroleum gas (LP-gas)
B	Gasoline	K	Dry-cleaning agents
C	Gasoline/Alcohol blends (≤15% alcohol)*	L	Laundry detergents
D	Naptha or kerosene	M	Dishwashing detergents
E	MPS gas	N	Atmospheric ozone
F	Manufactured or natural gas	O	Generated ozone
G	Diesel, fuel oil, or lubricating oil	P	Propylene
H	Heated fuel oil	R	Refrigerants*
I	Anhydrous ammonia

Global O-Ring’s UL-Listed O-Ring Offering

At Global O-Ring and Seal, we’re proud to offer a wide range of UL-listed o-rings designed to meet safety and performance standards. Certified under UL 157, our o-rings provide verified reliability across multiple materials, durometers, and application-specific requirements. Our certified options ensure dependable sealing performance where it matters most.

Range of Certified Materials

Global O-Ring and Seal offers UL-listed o-rings in a variety of elastomer compounds to support diverse industry needs. Our selection includes:

• Nitrile (NBR) in 50, 70, and 80 durometers for general-purpose fuel and oil resistance
• EPDM for excellent compatibility with detergents and ozone, rated to 302°F
• Silicone for high-temperature flexibility up to 437°F, with strong ozone and detergent resistance
• Fluorosilicone for extreme low-temperature performance and fuel compatibility
• Neoprene for refrigeration applications with reliable sealing down to -40°F
• Viton® (FKM) in 70 and 75 durometers, offering chemical and high-temperature resistance up to 482°F

Each compound is UL 157 certified for specific end-use categories, giving you confidence in their application suitability.

Tested to UL 157 Standards

All compounds listed below have been certified to UL 157. As part of the certification process, every material is approved for one or more defined end-use codes, which indicate its compatibility with substances such as fuels, refrigerants, detergents, and gases. These codes ensure the compound’s suitability for critical applications, helping customers meet exacting regulatory and compliance requirements with confidence.

Material	UL 157 End-Use Codes
Neoprene 70 Duro	R – Refrigerants
EPDM 70 Duro	L – Laundry detergents, M – Dishwashing detergents, N – Atmospheric ozone, O – Generated ozone
Fluorosilicone 70 Duro	B – Gasoline, C – Gasoline/Alcohol blends (≤15%), D – Naptha/Kerosene, G – Diesel/Fuel oil/Lubricants
NBR 50 Duro	F – Manufactured/Natural gas, G – Diesel/Fuel oil/Lubricants, J – Liquefied petroleum gas (LP-gas)
NBR 70 Duro	A – Extinguishing agents, B – Gasoline, C – Gasoline/Alcohol blends, D – Naptha/Kerosene, F – Manufactured/Natural gas, G – Diesel/Fuel oil/Lubricants, J – LP-gas
NBR 80 Duro	F – Manufactured/Natural gas, G – Diesel/Fuel oil/Lubricants, J – LP-gas
Silicone 70 Duro	L – Laundry detergents, M – Dishwashing detergents, N – Atmospheric ozone, O – Generated ozone
FKM 70 Duro	B – Gasoline, C – Gasoline/Alcohol blends, D – Naptha/Kerosene, G – Diesel/Fuel oil/Lubricants
FKM 75 Duro	B – Gasoline, C – Gasoline/Alcohol blends, D – Naptha/Kerosene, F – Manufactured/Natural gas, G – Diesel/Fuel oil/Lubricants, H – Heated fuel oil, J – LP-gas

For added assurance, our UL file number is available upon request for verification purposes. Product data sheets for each certified compound can be found on our UL Listed O-Rings page. If you have questions about material selection, certification scope, or suitability for application, our dedicated technical support team is ready to assist.

Why Choose Global O-Ring’s UL-Listed O-Rings

Global O-Ring and Seal offers a comprehensive selection of UL-listed o-rings, designed to meet the stringent requirements of safety-critical applications. With broad material coverage, our offering supports a range of end-use environments and performance requirements.

Our inventory depth and sourcing reliability further distinguish us. With millions of o-rings in stock and trusted supplier relationships, we help ensure fast and easy access to UL-listed products.

If you need UL-listed o-rings for your next project, visit our UL Listed O-Rings page to explore available materials, download data sheets, or request a quote. For assistance in selecting the right compound or verifying certification details, please contact our team.