O-ring seals are used at fluid-system interfaces where leakage control depends on the working media, pressure, temperature, movement and groove geometry. Provide the sealing conditions, O-ring dimensions or groove data to determine a suitable compound and specification.
Start with the operating environment rather than material alone. Confirm the sealing medium, temperature, pressure and movement before selecting a compound and size.
Confirm whether the seal contacts water, oil, fuel, chemicals, air or another gas. Check compatibility with the actual medium and concentration.
Compare continuous and peak temperatures with the recommended working range of the selected compound.
Specify normal pressure, peak pressure and pressure cycling. Higher pressure may require review of hardness, groove design and extrusion clearance.
Static seals remain between fixed surfaces, while dynamic seals face sliding, reciprocating or rotating movement that affects wear and lubrication requirements.
Use this comparison as a starting point. Final material selection should consider the actual medium, temperature, pressure, motion, groove design and required service conditions.
| Material Selection Overview | |
|---|---|
| NBR | General choice for oils, greases and many hydraulic fluids; commonly used where oil resistance and cost control are priorities. |
| EPDM | Commonly considered for water, steam, weather and ozone exposure; generally not selected for petroleum oils or fuels. |
| Silicone | Selected for flexibility across a broad temperature range and for clean-use applications where an appropriate grade is specified. |
| FKM | Consider for higher temperatures and demanding exposure to fuels, oils or chemicals when standard NBR is insufficient. |
| PU | Useful where abrasion, wear or mechanically demanding dynamic service is a primary concern. |
| PTFE | Provides strong chemical resistance and low friction, but its non-elastomeric behavior requires different groove, preload and recovery considerations. |
NBR, EPDM, Silicone, FKM and PU rely on elastic deformation and recovery in conventional O-ring grooves. PTFE behaves differently and should be reviewed separately for preload, groove design and operating conditions.
Choose a recognized size when the groove follows an established standard. Use a custom specification when dimensions, material or operating conditions require an application-specific solution.
AS568, metric or JIS-based projects
Drawing, sample or groove-based requirements
Use the operating condition to narrow the material choice before confirming compound grade, hardness and dimensions.
NBR is commonly considered for general oil-contact sealing, while FKM or HNBR may be reviewed for higher temperature or more demanding media.
EPDM is commonly considered for water, weather and ozone exposure. Fluid additives and operating temperature should still be confirmed.
Silicone or FKM may be evaluated depending on the sealing medium, temperature range and mechanical requirements.
FKM or PTFE may be considered for demanding chemical environments, but compatibility should be checked against the specific chemical, concentration and temperature.
Movement, surface finish, lubrication and abrasion should be reviewed together. PU or other application-specific compounds may be considered where wear is important.
Provide the actual operating conditions so the material and specification can be reviewed before quotation.
State the liquid, gas, oil, fuel or chemical in contact with the seal, including concentration where relevant.
Provide continuous and peak temperatures together with normal pressure, maximum pressure and pressure cycling if applicable.
Confirm whether the seal is static, reciprocating or rotating, and include groove dimensions or an assembly drawing when available.
Provide the O-ring size or standard code, required hardness or existing material, applicable compliance needs and estimated order quantity.
Explore complementary sealing solutions from our comprehensive product catalog.
Our engineering team reviews your specs and responds within 24 hours with material recommendations and competitive pricing.
