O-Ring Material Selection Guide

How Do I Choose The Right O-Ring Material?

Selecting the right o-ring material requires a comprehensive evaluation of the entire operating environment. Chemical exposure, pressure, motion, wear, regulatory standards, and service conditions all interact to determine seal performance and reliability. ESP partners with engineering teams to systematically evaluate these variables and compare material families, compounds, and manufacturer options. Our goal is to identify the optimal solution for each application, balancing performance, compliance, and manufacturability.

Not sure where to start?

O-Ring Material Comparison Chart

This chart provides a baseline for comparing common o-ring materials. Actual performance depends on compound formulation and the specific demands of your application.

Material	ASTM	Shelf Life (Years)	Hardness (Shore A)	Low Temp (F°)	High Temp (F°)	Recommended For
Nitrile (Buna)	NBR	15	40 - 90	-34	+212	Petroleum oils and fuels, silicone oils and greases, propane, ethylene glycol, butane, vegetable, mineral oils and greases, dilute acids, water and steam applications (below 212°F).	General NBR Information
Hydrogenated Nitrile	HNBR	15	50 - 90	-40	+300	Petroleum oils and fuels, R134a refrigerant gas, silicone oils and greases, ozone applications, improved compression set characteristics, vegetable and animal fats, fluids, water and steam (up to 300° F).	General HNBR Information
Fluorocarbon (Viton®)	FKM	25	55 - 90	-15	+400	Petroleum oils and fuel, mineral and vegetable oil and grease, silicone oils and greases, hard vacuum applications, solvents, water or steam (up to 400°F).	General FKM Information
Perfluoroelastomer	FFKM	25	65 - 90	-15	+572	Water and steam applications (below 212°F), petroleum oils and fuels, silicone oils and greases, propane, ethylene glycol, butane, vegetable, mineral oils and greases, and dilute acids.	General FFKM Information
Ethylene Propylene	EPDM	25	40 - 95	-70	+300	Hot water and steam with special compounds, gycol based and silicone-based brake fluids, ozone, aging and weather resistance, cleaning agents, silicone oil and grease, alcohols, ketones, esters.	General EPDM Information
Silicone	VMQ	25	20 - 80	-65	+400	For static applications Silicone o-rings offer high suitability in medical, food, pharmaceutical, semiconductor, automotive, aerospace, and electronics. Excellent in dry heat and ozone applications.	General VMQ Information
Fluorosilicone	FVMQ	25	40 - 80	-100	+350	FVMQ is widely used in aerospace, jet fuel applications, engine gaskets, automotive emission control systems, fuel pumps and tank systems. Not recommended for dynamic sealing.	General FVMQ Information
Polyacrylate	ACM	15	40 - 90	-5	+350	Optimal environments include engines and transmissions with good resistance to petroleum fuels and oils, automatic transmission fluid, type A power steering fluid.	General ACM Information
Butyl Rubber (Isoprene)	IIR	15	30 - 90	-75	+250	Recommended for general purpose applications, vacuum, and low compression set.	General IIR Information
AFLAS®	TFE/P	25	60 - 90	+15	+450	Phosphate esters, amines, steam and hot water, automotive engine coolants, motor oils, steering fluids and some brake fluids.	General TFE/P Information
Polyurethane	AU	5	40 - 90	-40	+180	Can be used with propane, butane, mineral oil and grease, silicone oil and grease.	General AU Information

O-Ring Material Comparison Tool

Need a deeper comparison? Compare o-ring material properties by elastomer family.

Evaluate By

Key Properties
Operating Conditions
Industry
Compliance
Brand Compound

Evaluate Key O-Ring Material Properties

The most effective o-ring material is one that delivers consistent performance across all operating conditions. Begin by defining the full range of service environments and requirements the seal will encounter over its lifecycle.

Media & Chemical Exposure

Document all fluids, gases, lubricants, cleaning agents, and process chemicals that may contact the seal. Compatibility must be confirmed for each, as materials that perform well in one environment may degrade or fail in another.

Temperature

Evaluate both continuous operating temperatures and transient extremes. Elevated temperatures can accelerate degradation and compression set, while low temperatures may reduce flexibility and compromise sealing integrity.

Pressure

Increased system pressure raises the risk of extrusion and may necessitate harder compounds, optimized clearances, backup rings, or additional design modifications.

Motion

Static, reciprocating, rotary, and oscillating motions each impose unique demands on sealing systems. In dynamic applications, factors such as friction, wear, lubrication, speed, and surface finish require careful consideration.

Service Environment

Environmental factors including abrasion, ozone, weathering, steam, vacuum, pressure cycling, and installation conditions must be factored into material selection to ensure long-term reliability.

Regulatory & Industry Requirements

Certain applications demand compound-specific approvals, certifications, traceability, purity, or documentation. These requirements should be integrated into the material selection process from the outset.

O-Ring Material Selection Tool

Not sure where to start? Answer a few questions about your application and we’ll help narrow your options based on operating conditions, media, and requirements.

Evaluate by Operating Conditions

When primary operating challenge is identified, starting with the relevant condition can streamline material selection before narrowing to specific elastomer families.

High Temperature O-Ring Materials

Low Temperature O-Ring Materials

High Pressure O-Ring Materials

Increased system pressure raises the risk of extrusion and may necessitate harder compounds, optimized clearances, backup rings, or additional design modifications.

Chemical Resistant O-Ring Materials

Evaluate by Industry

Material requirements differ widely across industries. Factors such as operating fluids, temperature, pressure, cleaning protocols, purity standards, environmental exposure, and documentation must be considered to select the appropriate o-ring material or compound.

AI Infrastructure

AI and data center cooling systems demand materials compatible with water-glycol coolants, temperature cycling, extended service intervals, and stringent reliability targets. Material selection should be tailored to each component, including pumps, valves, quick disconnects, heat exchangers, and coolant distribution units.

Food & Beverage

Food-processing equipment often requires compounds that withstand aggressive cleaning chemicals, washdown, steam, and repeated CIP or SIP cycles, while maintaining compliance with relevant food-contact standards.

Aerospace & Defense

Aerospace and defense applications require controlled material specifications, full traceability, comprehensive documentation, and reliable performance under demanding temperature, pressure, fuel, and environmental conditions.

Chemical Processing

Aggressive chemicals, elevated temperatures, high concentrations, and prolonged exposure make elastomer selection a critical factor in the reliability of chemical-processing equipment.

Oil & Gas

Oil and gas applications expose seals to hydrocarbons, aggressive chemicals, high pressures, temperature extremes, and rapid pressure fluctuations. Material selection must address these combined challenges.

General Industrial

Industrial equipment can present a wide range of sealing conditions involving lubricants, chemicals, temperature, pressure, motion, abrasion, and outdoor exposure. Material selection should be based on the specific operating environment rather than a general-purpose material assumption.

Evaluate by Compliance Requirement

Certain applications require compound-specific approvals, certifications, specifications, or documentation in addition to material compatibility. It is essential to confirm that the exact compound, not just the elastomer family, meets all applicable standards.

FDA-Compliant
Food and beverage applications may require compounds formulated with ingredients appropriate for applicable FDA food-contact requirements.

NSF 51
NSF/ANSI 51 applies to materials and components used in commercial food equipment and can influence compound selection for food-processing applications.

NSF 61
O-rings used in potable-water systems may require NSF/ANSI 61 certification for contact with drinking water.

UL-Recognized Materials
Electrical equipment and enclosure applications often require elastomer compounds evaluated to UL standards. Because recognition is compound-specific, the precise material must be verified for each application.

Aerospace and Military Specifications
Aerospace and defense applications specify particular elastomer compounds, material specifications, traceability, and documentation. Compliance requires verification at the compound level, not just by material family.

Evaluate O-Ring Compounds by Manufacturer

Selecting an elastomer family is only part of the process.

Individual compounds within the same material family can differ in temperature capability, chemical resistance, hardness, compression set, low-temperature performance, certifications, and other properties. ESP works with multiple material and sealing manufacturers, giving engineers the flexibility to evaluate compound options based on performance requirements, availability, documentation, and qualification needs.

Need An Alternate or Second Source?

Already have an existing material, compound, or part specification?

ESP can help evaluate alternate materials, compound equivalency, documentation, and qualification requirements when you need a second source or replacement for an existing seal.

Need Help Selecting an O-Ring Material?

When several operating conditions must be balanced at once, material selection can become complex. Share your media, temperature, pressure, motion, regulatory requirements, and application conditions with ESP. Our application engineering team can help evaluate material families and compound options for your application.

Material Selection Application
Material Selection