EPDM vs. NBR Rubber: Which Gasket Material Is Right for Your Application?

Choosing the right gasket material is essential for achieving a dependable, long-lasting seal in waterworks and fire protection systems. Two of the most common elastomers used in these applications are EPDM (Ethylene Propylene Diene Monomer) and NBR (Nitrile Butadiene Rubber). While both are durable and widely used across the industry, they perform very differently when it comes to water exposure, oil contact, and temperature range.

Understanding how each behaves helps ensure your pipeline, joint, or coupling maintains proper sealing under real-world conditions.

Water Exposure

EPDM is the leading choice for any system that involves water or steam. It provides outstanding resistance to water, moisture, and weathering, making it ideal for municipal water systems, ductile iron pipe gaskets, and fire protection lines. EPDM maintains flexibility and sealing integrity even with long-term water contact or outdoor exposure. It does not swell, crack, or lose elasticity, which makes it exceptionally reliable for wet environments.

NBR, by comparison, is not intended for continuous exposure to water. While it can tolerate brief contact, long-term moisture can cause it to absorb water and lose its sealing performance. For any application where the gasket is in constant contact with water or humid conditions, EPDM is the clear choice.

Oil and Fuel Exposure

In systems where occasional contact with lubricating oils or fuels is expected, NBR performs better. It has excellent resistance to petroleum-based fluids and maintains its sealing capability when exposed to oil, grease, or similar substances.

EPDM, however, is not compatible with oil or hydrocarbon exposure. These substances can cause EPDM to swell and degrade, compromising the seal. For this reason, it should only be used in pure water or air service, while NBR can be chosen for applications that may involve light oil contamination.

Temperature Range

Temperature stability is another key factor in gasket performance. EPDM operates effectively from –40°F to 250°F (–40°C to +120°C). This makes it suitable for both cold-weather installations and systems subject to moderate heat, such as fire mains or above-ground pipelines exposed to temperature fluctuations. EPDM remains flexible in cold climates and resists cracking or hardening over time.

NBR has a slightly narrower temperature range, operating from –30°C to +120°C. It performs well in stable temperature conditions but is less suited to extreme cold. In higher heat environments, NBR can harden or lose flexibility over time. When temperature variability is a factor, EPDM offers better long-term resilience.

Choosing the Right Material for Waterworks Applications

The choice between EPDM and NBR ultimately depends on the environment and media your gasket will face:

• Choose EPDM when the gasket will be exposed to water, steam, or outdoor conditions. It provides superior resistance to weathering, ozone, and temperature fluctuations, making it ideal for fire protection systems, ductile iron pipes, and municipal water distribution.
  
  
• Choose NBR when the gasket may occasionally come into contact with oil, grease, or fuel residue. It maintains integrity in oily environments but should not be used for water systems where constant moisture is present.
  
  

Both materials have their place in the waterworks and fire protection industry — the key is selecting the right one for the specific conditions your system will face. Choosing correctly ensures consistent sealing performance, reduced maintenance, and longer service life for your infrastructure.

​For more than 50 years, we’ve partnered with clients who demand reliability and a supplier that understands their systems, pressures, and priorities. Contact us today to explore certified solutions that ensure lasting performance in your applications.