EPDM vs NBR vs Viton gaskets for vent pipes

Using the wrong gasket material in a vent pipe system doesn’t just lead to leaks—it can trigger system imbalance, corrosion, or even failure under pressure. Over the years, I’ve seen these problems show up in both rooftop flue lines and indoor ducting systems.

EPDM, NBR, and Viton are the three most common rubber materials for vent pipe gaskets. EPDM is excellent for water and weather resistance, NBR is better for oil and fuel exposure, and Viton provides the best chemical and high-temperature resistance.

Let’s break down their strengths, weaknesses, and best-fit applications so you can choose confidently for your system.

Why is EPDM the most common for vent pipes?

EPDM is widely used in outdoor vent systems because it resists ozone, sunlight, water, and steam. It keeps its flexibility in cold temperatures and performs well in hot vent ducts carrying moist air or mild chemicals.

Use EPDM for vent pipes exposed to rain, sun, steam, or mildly corrosive environments.

What it does well:

• Temperature range: -40°F to 212°F (some types up to 300°F)¹
• Excellent resistance to UV, ozone, water, and steam²
• Moderate resistance to weak acids and bases
• Long service life outdoors³
• Good compression recovery

When to avoid:

• Systems carrying oil, fuel vapors, or hydrocarbons
• Indoor systems with oil-mist-laden exhaust

When is NBR the better option?

Nitrile (NBR) gaskets are designed to resist oils, fuels, and hydraulic fluids. That’s why I recommend them for vent lines in workshops, fuel storage rooms, or diesel generator exhaust ducts.

Choose NBR if your vent system handles petroleum-based vapors or oily gases, and is installed in a covered or enclosed space.

Key benefits:

• Handles -30°F to 150°F (some types up to 250°F)
• Excellent fuel and oil resistance⁴
• Good abrasion performance and sealing under pressure⁵
• Lower material cost

Limitations:

• Poor resistance to ozone and UV⁶—unsuitable for exposed outdoor use
• Will crack and harden in vent pipes exposed to sunlight or steam

When is Viton necessary?

Viton (also known as FKM) is the highest-performing rubber material in terms of chemical and heat resistance. I only recommend it when the system deals with strong acids, solvents, or very high exhaust temperatures.

Viton is ideal for aggressive chemical vents, high-heat flue ducts, or systems where failure isn’t an option.

Its standout features:

• Temperature range: -10°F to 300°F (some grades to 400°F)⁷
• Outstanding resistance to fuels, acids, solvents, and industrial gases⁸
• Excellent sealing under sustained heat and pressure
• Low gas permeability—ideal for airtight seals
• Long service life even in harsh environments⁹

Cautions:

• Higher cost—2–3 times the price of EPDM or NBR
• Less flexible than EPDM in extreme cold
• Overkill for basic HVAC or DWV systems

Comparison chart: Which material fits your vent system?

Here’s a complete side-by-side overview I often share with engineers and purchasing teams:

My practical recommendation

• Use EPDM for general-purpose vent pipe sealing in HVAC, hot water vents, flue ducts, or outdoor stack systems.
• Use NBR when you’re handling diesel exhaust, oily vapors, or lubricated compressed air—provided the system is indoors or protected.
• Use Viton when temperature exceeds 250°F or the system carries harsh chemical vapors or solvents.

At Julong Rubber, we offer all three materials molded into vent pipe gaskets. For some European customers, we also provide pre-lubricated versions and flame-rated compounds for EN and UL compliance.

Conclusion

EPDM, NBR, and Viton all serve specific roles in vent pipe systems. The right choice depends on what’s flowing through the pipe, how hot it gets, and where the system is located. Choose wisely—and your gasket will last.