NBR vs EPDM: What's the Difference and When Should You Use Each?
What's the difference between NBR and EPDM, and where does each perform best? See the comparison chart for oil, water and heat resistance.
About this article
This article was prepared by the technical team at Hamta Polymer Zayandeh Rood Industries. Contact our specialists for application guidance and the right option for your industrial need.
What's the difference between NBR and EPDM, and where does each perform best? See the comparison chart for oil, water and heat resistance.
# NBR vs EPDM: What's the Difference and When Should You Use Each?
NBR (nitrile) and EPDM are the two most widely used industrial elastomers, and their applications are almost exact opposites: NBR is engineered for contact with oil and fuel, while EPDM performs best against water, steam, and alkaline chemicals. Swapping one for the other is the single most common cause of premature seal failure in industry. Below, we cover the structural differences, chemical resistance, and correct use case for each.
This article is part of our Complete Guide to Rubber Seals; if you're not familiar with the basic O-ring types, start there first.
Table of Contents
- What's structurally different between NBR and EPDM?
- Technical comparison chart: NBR vs EPDM
- When should you use NBR?
- When should you use EPDM?
- The common mistake: mixing up these two materials
- FAQ
What's Structurally Different Between NBR and EPDM?
NBR (nitrile-butadiene rubber) is made from a copolymer of acrylonitrile and butadiene; the acrylonitrile group increases the molecule's polarity, which is exactly what gives it strong resistance to non-polar (petroleum-based) oils. EPDM (ethylene propylene diene monomer), by contrast, has a fully non-polar, saturated structure, making it very stable against water, steam, ozone, and alkaline chemicals — but that same lack of polarity means it swells fast on contact with petroleum oils.
Technical Comparison Chart: NBR vs EPDM
| Property | NBR (Nitrile) | EPDM |
|---|---|---|
| Resistance to mineral oil | Excellent | Poor |
| Resistance to water and steam | Poor to fair | Excellent |
| Resistance to ozone and UV | Poor | Excellent |
| Resistance to alkalis | Fair | Excellent |
| Max continuous operating temp. | 100–120°C | 130–150°C |
| Relative cost | Low to medium | Medium |
When Should You Use NBR?
NBR is the industry standard for parts in direct contact with engine oil, hydraulic oil, grease, or fuel: fuel pump gaskets, hydraulic system O-rings, oil hoses, and gearbox seals are all common applications. For a deeper dive into oil- and fuel-resistant material selection, see our guide on oil- and fuel-resistant rubber.
When Should You Use EPDM?
EPDM is the right pick for parts exposed to water, steam, alkaline detergents, or sunlight and ozone: cold- and hot-water plumbing gaskets, automotive body weatherstripping (constantly exposed to sunlight), steam hoses, and industrial washdown equipment components are all common EPDM applications.
The Common Mistake: Mixing Up These Two Materials
The most common mistake in industrial projects is ordering an EPDM O-ring for a system that gradually gets contaminated with oil or grease (for example, an outer seal on a hydraulic pump that appears to face "only water and air" but actually gets sprayed with oil in practice) — or, the reverse, using NBR outdoors in direct sunlight, which causes early surface cracking due to its sensitivity to ozone.
FAQ
Can EPDM be substituted for NBR in an oil system?
No. EPDM swells and loses effectiveness quickly on contact with petroleum oils, and replacing NBR with it in oil-based systems will cause premature leaks.
Why does my car's rubber body seal crack after a while?
If it's made of NBR, its sensitivity to ozone and UV means continuous sun exposure causes surface cracking; EPDM is the better choice for this application.
Which is better for sealing a building's hot water system?
EPDM, thanks to its excellent resistance to water and steam and its stability at high temperature, is the industry standard for building/plumbing applications.
Is NBR more expensive than EPDM?
Usually not — both materials sit in a similar price range, and the choice should be based on the fluid in contact, not price alone.
Is EPDM resistant to gasoline?
No. EPDM has no reliable resistance to gasoline or other petroleum products, and using it in such an environment is not recommended.
Sources & References
This guide draws on the industrial standards ASTM D2000, ASTM D471, and technical guidance from Trelleborg Sealing Solutions on elastomer selection based on fluid type.
Summary
If your part is in contact with oil, grease, or fuel, choose NBR. If it's exposed to water, steam, alkaline detergents, or sunlight, EPDM is the right pick. For projects where both conditions apply simultaneously, you'll need a more specialized material like FKM. If you're not sure which material fits your project, our technical team offers a free consultation and price quote.
Have a technical question?
Hamta Polymer specialists are ready to advise on materials, standards and rubber component specifications.