EPDM rubber looks simple from the outside, but misunderstanding its specs can cause sealing failure or costly downtime.
EPDM rubber is defined by a specific range of technical properties such as hardness, temperature resistance, tensile strength, and certifications, which make it suitable for various industrial applications.
If you're sourcing EPDM for HVAC, automotive, or industrial seals, getting the specs right isn’t just helpful—it’s critical.
What is the hardness range of EPDM rubber?
Choosing the wrong hardness can cause compression set, leakage, or poor fit.
EPDM rubber is typically available in hardness levels ranging from 40 to 90 Shore A, with 60–70 Shore A being the most commonly used.
✅ Shore A1 Hardness Explained
The Shore A scale measures how hard a rubber feels when pressed. For EPDM, the sweet spot is usually 60–70 Shore A, which balances flexibility and durability.
🛠️ Typical Hardness Use Cases
| Shore A | Typical Use Case | Remarks |
|---|---|---|
| 40 | Low-pressure seals, soft gaskets | High flexibility, low strength |
| 60 | HVAC and plumbing gaskets | Industry standard balance |
| 70 | Automotive, outdoor seals | Durable with good compression |
| 90 | High-load mechanical sealing | Rigid, harder to install |
📌 I often recommend 60 Shore A to my Dutch client Jet, who values balance in compression recovery2 and durability. When we switched from 70 to 60 in one HVAC project, the installation became smoother, and the leak rate dropped.
🔍 What Happens If You Choose the Wrong Hardness?
- Too soft: The rubber gets crushed and leaks.
- Too hard: It doesn’t compress well and may not seal.
Always consider groove size, compression force, and temperature when selecting hardness.
What is the temperature range of EPDM?
Failing seals in extreme heat or cold often come down to poor temperature matching.
EPDM rubber can typically operate between -50°C to +150°C, with special grades going up to +180°C.
✅ EPDM’s Thermal Resilience
EPDM3 is one of the few rubbers that remain flexible even in freezing winters. I once received a complaint about a gasket stiffening in a Dutch winter. Turned out, the supplier had used a generic black rubber, not EPDM.
🛠️ Rubber Temperature Comparison Table4
| Material | Min Temp (°C) | Max Temp (°C) | Notes |
|---|---|---|---|
| EPDM | -50 | +150 / +180 | Excellent for steam, weather |
| NBR | -30 | +100 | Not UV or ozone resistant |
| Silicone | -60 | +200 | Expensive, food-safe |
| Neoprene | -40 | +120 | Moderate performance |
📌 If you’re in a region with temperature swings5—like France or Germany in winter—EPDM is almost always the safest choice.
What certifications does EPDM rubber meet?
David, like most EU buyers, always asks: “Is it certified?” Without compliance, customs or clients may block shipments.
EPDM can comply with certifications such as RoHS, REACH, FDA, WRAS, NSF-61, and UL 94, depending on the formulation.
✅ Common Certifications for EPDM
| Certification | What It Means | Where It’s Needed |
|---|---|---|
| RoHS | Free of hazardous heavy metals | All EU electronics and components |
| REACH | Safe for human health and environment | EU general goods |
| FDA6 | Food contact safe | Food processing, kitchenware |
| UL 94 | Flame resistance | Electrical housings, appliances |
| WRAS / NSF-617 | Safe for drinking water | Potable water systems, plumbing |
📌 Some clients ask for EPDM with both FDA and WRAS. That’s not common, but yes—it’s possible with the right compound.
🔧 Tips for Specifying EPDM Certifications
- Always ask your supplier to provide certification test reports8.
- Certifications may vary by color. FDA EPDM is often white or blue.
- WRAS and NSF usually require third-party lab testing.
At Julong, I’ve helped clients pass strict audits by supplying EPDM gaskets with certified material batches. We maintain documentation for traceability and offer batch-specific compound certificates.
What are the mechanical properties of EPDM?
Don’t just focus on hardness—tensile and elongation matter too.
EPDM typically offers tensile strength from 7 to 21 MPa and elongation at break from 300% to 600%.
✅ Tensile Strength & Elongation
Tensile strength tells you how much load EPDM can handle before breaking. Elongation indicates flexibility before it snaps.
🛠️ EPDM Mechanical Properties Table
| Property | Typical Range | Notes |
|---|---|---|
| Tensile Strength9 | 7–21 MPa | Higher = stronger rubber |
| Elongation10 | 300%–600% | Higher = more stretchable |
| Compression Set11 | <25% (at 70°C, 22h) | Lower = better sealing recovery |
| Tear Resistance | Moderate | Not ideal for dynamic tearing |
📌 I’ve worked on pump impeller seals where the EPDM had to stretch and recover over 1000 cycles. Selecting an EPDM with high elongation was critical to avoid cracking.
🔍 Why It Matters
In dynamic systems—pistons, diaphragms, even simple gaskets—understanding how EPDM behaves under load prevents failure and saves money.
What color and formulation options are available?
Many assume EPDM is always black. That’s not true—and it can be a problem.
EPDM comes in black, white, grey, blue, and custom colors, each suited to different environments and regulations.
✅ Color Isn’t Just for Looks
In FDA or WRAS applications, black may be rejected. White or blue is preferred for hygiene.
🛠️ EPDM Color Usage Table
| Color | Use Case | Notes |
|---|---|---|
| Black | General industrial use | Contains carbon black for UV |
| White | FDA, food contact | No carbon black |
| Blue | Water systems, food | Easier visual detection |
| Grey | Aesthetic applications | Custom |
🔧 Special Formulations
- Peroxide-cured EPDM: Higher heat resistance, better compression set
- Sulfur-cured EPDM: Lower cost, general use
- Oil-resistant EPDM: Not typical, but available
📌 When customer requested blue EPDM gaskets12 for a school kitchen project in Rotterdam, our team formulated and extruded a WRAS-compliant13 blue compound that passed inspection in one go.
Conclusion
Understanding EPDM specs avoids mismatches, delays, and sealing failures in industrial applications.
Need EPDM rubber seals for your project?
Contact Julong Rubber or Request a Quote to get premium EPDM parts with customized hardness, temperature resistance, and certified compounds.
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Understanding the Shore A hardness scale is crucial for selecting the right rubber for various applications, ensuring optimal performance. ↩
Learning about compression recovery will enhance your understanding of rubber materials and their suitability for specific applications. ↩
Explore the advantages of EPDM rubber, including its flexibility in extreme temperatures, making it ideal for various applications. ↩
This table provides a quick reference for understanding how EPDM stands out against other rubber types in temperature extremes. ↩
Learn about the impact of temperature fluctuations on rubber materials, crucial for selecting the right type for your needs. ↩
Understanding FDA certification is crucial for ensuring safety in food contact materials. Explore this link to learn more about its significance. ↩
Discover the importance of WRAS / NSF-61 certification for drinking water safety and compliance in plumbing systems. ↩
Learn how to obtain certification test reports to ensure compliance and quality in your materials. This is essential for informed sourcing. ↩
Understanding tensile strength is crucial for selecting materials that can withstand loads without breaking, ensuring durability and safety. ↩
Exploring elongation helps in choosing the right rubber for applications requiring flexibility and resilience, preventing premature failure. ↩
Learning about compression set is vital for ensuring effective sealing in dynamic systems, enhancing performance and longevity. ↩
Explore the advantages of blue EPDM gaskets, especially in food safety and compliance, to enhance your projects. ↩
Learn about WRAS compliance to ensure your materials meet necessary standards for water safety. ↩
