Choosing the wrong gasket material can lead to seal failure, costly rework, or poor performance in HVAC duct systems.
EPDM is the preferred material for most spiral duct fittings due to its weather resistance and cost-efficiency, while silicone gaskets are used in extreme temperature or sensitive environments.
Here’s how the two materials compare—so you can choose the right gasket for your ventilation project.
Here’s how the two materials compare—so you can choose the right gasket for your ventilation project.
Temperature Resistance1
| Material | Temperature Range | Suitability |
|---|---|---|
| EPDM2 ✅ | -40°C to +120°C (up to 150°C short-term) | Great for most HVAC conditions ✅ |
| Silicone3 | -60°C to +230°C (up to 250°C+) | Best for high-temp or low-temp zones |
EPDM handles most ventilation applications.
Use silicone only when ducts carry high-temperature exhaust or pass through freezing zones.
Weathering and UV Resistance
Both materials resist ozone and aging, but:
- EPDM ✅ is the industry standard for outdoor duct systems, with excellent durability under sun, rain, and wind.
- Silicone performs well too, but may degrade faster in acidic or polluted air unless specially formulated.
For rooftop ducts, wall vents, and exposed dampers, EPDM offers the best price-to-performance ratio4.
Chemical Compatibility
| Material | Resistant To | Not Recommended For |
|---|---|---|
| EPDM ✅ | Water, steam, alcohols, weak acids | Oils, fuels, hydrocarbons |
| Silicone | Water, oxygen, many chemicals, oils | Strong acids, concentrated solvents |
For general ventilation air (moisture, CO₂, mild gases), EPDM is enough.
If the duct handles chemical vapors5, oils, or cleanroom-grade air, use silicone.
Compression Set and Flexibility
- Silicone ✅ retains elasticity longer in very hot environments.
- EPDM ✅ provides excellent compression recovery6 in normal HVAC ranges.
If your system includes repeated thermal cycling7 or access panels, silicone offers slightly better long-term compression set resistance.
Cost and Availability
EPDM gaskets8 are:
- Cheaper (typically 30–50% less than silicone) ✅
- Easier to extrude into custom profiles
- More widely available in standard sizes for spiral duct fittings
Silicone is:
- More expensive due to material and curing costs
- Used in niche or regulated environments (pharma, food, lab)
Summary: Which One to Choose?
| Criteria | Best Material |
|---|---|
| Standard HVAC systems | EPDM ✅ |
| Outdoor vent sealing | EPDM ✅ |
| High-temperature air (>200°C) | Silicone ✅ |
| Chemical vapors or oils present | Silicone ✅ |
| Cost-sensitive projects | EPDM ✅ |
| FDA/medical/cleanroom | Silicone ✅ |
Julong Rubber: Spiral Duct Gasket Options
We offer both EPDM and silicone gaskets9 in profiles for:
- Spiral ducts (U, triple-lip, O-ring)
- Dampers and air control components
- Access doors and cleanroom sealing
- Standard diameters from 80 mm to 1250 mm
All gaskets are manufactured to meet SMACNA Class C/D10 or Eurovent airtightness standards.
Conclusion
For most spiral duct projects, EPDM is the most practical and effective material—it seals well, lasts long outdoors, and keeps costs down. Choose silicone when temperature or chemical exposure demands it.
Need help picking the right gasket material?
Contact Julong Rubber or Request a Quote to get custom or standard EPDM and silicone gaskets for spiral duct fittings.
Or message us directly on WhatsApp:
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Understanding temperature resistance helps you select the right gasket for your specific HVAC needs, ensuring efficiency and safety. ↩
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EPDM is widely used for its durability and temperature range, making it a reliable choice for various HVAC systems. ↩
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Silicone gaskets are ideal for extreme temperatures, ensuring optimal performance in high or low-temperature environments. ↩
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Discover why EPDM is favored for its excellent price-to-performance ratio in rooftop duct applications. ↩
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Learn about the impact of chemical vapors on material selection, ensuring you choose the right materials for safe and effective ventilation systems. ↩
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Understanding compression recovery is crucial for selecting the right gasket material for HVAC applications, ensuring efficiency and longevity. ↩
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Exploring the effects of thermal cycling can help you choose the best gasket for your system's specific conditions and needs. ↩
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Learn about the advantages of EPDM gaskets to make informed decisions for cost-effective and efficient HVAC solutions. ↩
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Learn about the versatility and high-temperature resistance of silicone gaskets, essential for specific HVAC applications. ↩
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Understanding SMACNA standards can help ensure your duct systems are efficient and compliant, enhancing overall performance. ↩
