EPDM O-Rings
The preferred sealing material for water, steam, HVAC systems and outdoor applications requiring ozone and weathering resistance.
Overview
EPDM (Ethylene Propylene Diene Monomer) is the leading elastomer for water, steam and weather-exposed sealing applications. Its saturated polymer backbone provides outstanding resistance to ozone, UV radiation and atmospheric aging - properties that make it essential for outdoor, HVAC and water treatment applications where other elastomers deteriorate rapidly.
With a service temperature range of -50C to +150C and excellent resistance to hot water and low-pressure steam, EPDM is specified across heating systems, water treatment plants, food processing equipment and building HVAC installations. FDA-compliant grades are available for potable water and food contact applications.
The critical limitation of EPDM is its poor compatibility with petroleum oils and fuels. It must never be used in hydraulic systems with mineral oil-based fluids. For mixed water and oil environments, consult our engineering team for compound selection guidance.
Material Properties
| Temperature Range | -50C to +150C (-58F to +302F) |
| Hardness Range | 40-90 Shore A |
| Tensile Strength | 10-18 MPa |
| Compression Set (70h/150C) | <=25% |
| Specific Gravity | 0.86-0.87 |
| Color (standard) | Black |
| FDA Grade | Available |
Typical Applications
Water Treatment
Pipeline flange seals, valve O-rings and pump seals in potable water and wastewater systems
HVAC
Heating system seals, cooling circuit O-rings and air handling unit seals
Food & Beverage
FDA-grade seals for food processing equipment, dairy systems and beverage dispensing
Steam Systems
Low and medium pressure steam seals, autoclaves and steam-jacketed piping
Outdoor Equipment
Weather-exposed seals, outdoor electrical enclosure seals and solar panel mounting seals
Chemical Compatibility Summary
Compatible With
- - Hot water and steam
- - Polar solvents
- - Glycol-based brake fluids
- - Skydrol
- - Dilute acids and alkalis
Incompatible With
- - Mineral oils
- - Hydrocarbon fuels
- - Aromatic hydrocarbons
- - Chlorinated solvents
- - Turpentine
Compare Nearby Materials
Further Reading
EPDM vs Silicone
The practical tradeoff between steam resistance, low temperature, and clean static sealing.
Read articleBest Material for Steam
Why peroxide-cured EPDM is usually the starting point for steam duty.
Read articleKey Advantages
Best Choice for Water and Steam
EPDM performs reliably in hot water, low-pressure steam and glycol-based systems where NBR and FKM are poor fits.
Outstanding Weather Resistance
Its resistance to ozone, UV and aging makes EPDM ideal for outdoor service and equipment exposed to changing climates.
Food and Potable Water Grades Available
FDA and water-contact compliant EPDM grades are available for food processing, beverage systems and clean water applications.
Broad Low-Temperature Flexibility
EPDM remains flexible in cold environments, making it practical for outdoor, refrigeration-adjacent and variable-temperature systems.
Frequently Asked Questions - EPDM
Can EPDM O-rings handle steam?
Yes. EPDM is one of the best elastomers for saturated steam service up to roughly 150C. For superheated steam above this range, PTFE or metal seals are better options.
Is EPDM safe for drinking water applications?
Yes. FDA-grade and potable-water approved EPDM compounds are available. Specify food or water grade when ordering.
Why can EPDM not be used with hydraulic oil?
EPDM has very poor resistance to petroleum-based oils and fuels. Exposure causes swelling, softening and rapid loss of sealing force.