Maximum Continuous Operating Temperature of FKM

Fluoroelastomers (FKM), often recognised under the brand name Viton®, are one of the most commonly used elastomers for sealing applications across many industries. It’s particularly popular within the Chemical Processing Industry (CPI) as a result of its high thermal stability and strong resistance to a wide range of aggressive chemicals as an especially chemical-resistant rubber.

Before choosing FKM for your sealing application, it’s important to understand the full extent of its attributes and whether it’s a suitable material for your requirements. Specifically, this blog from TRP Polymer Solutions takes an in-depth look at FKM’s maximum continuous operating temperature and how FKM O-rings’ temperature range makes them the most optimal choice for many CPI processes.

Understanding FKM’s continuous temperature limit

For most standard FKM compounds, the practical continuous operating range is typically up to around 200°C. This is the temperature at which the material can perform reliably over long periods without significant degradation.

The elastomer can tolerate higher temperatures in short bursts. As a general FKM guideline, temporary excursions to around 230°C are generally possible, and specialised grades such as Viton ETP can reach peak resistance up to approximately 250°C. However, these higher values are not intended for continuous exposure and should be treated as short-term limits rather than design targets.

At the lower end, standard grades usually perform down to around -20°C, while specialist formulations can extend this to between -40°C and -55°C in static applications, depending on the compound.

The importance of FKM formulation

FKM is not a single uniform material, and the performance of the material varies depending on numerous factors, such as the polymer type, curing system and compound formulation. These factors not only influence temperature capability between FKM variants but also compression set, chemical resistance, and long-term sealing behaviour.

Because of this, two FKM O-rings with the same nominal temperature rating can behave quite differently in service depending on how they are formulated.

Continuous vs short-term exposure

A key consideration in CPI applications is the difference between sustained operating temperature and occasional peaks. While FKM can survive short periods above its continuous limit, prolonged exposure above around 200°C typically leads to hardening, reduced elasticity, and a gradual decline in sealing performance.

In practice, this means that designing materials around continuous conditions rather than the peak temperatures that they can withstand infrequently is essential for achieving reliable long-term operation.

Why FKM is chosen for CPI applications

FKM continues to be one of the most reliable choices for CPI sealing applications because it offers a strong balance of thermal stability and chemical resistance. It is commonly used in environments involving hydrocarbons, acids, solvents and a wide range of aggressive process fluids.

FKM’s temp range and resistance to various harsh substances make it particularly suitable for components such as valve seats, pump seals, shaft seals, and static gaskets where both heat and chemical exposure are present. In many instances, it’s selected not because it is the highest-temperature elastomer available, but because it provides the most balanced overall performance profile. Its maximum continuous operating temperature of around 200°C is suitable for various CPI applications while still maintaining good chemical and compression set resistance. 

Temperature-resistant FKM at TRP Polymer Solutions

Selecting the correct FKM grade for your application is rarely just a question of temperature resistance. In CPI applications and across many industries, factors such as media compatibility, pressure, dynamic movement, and expected service life all need to be equally considered.

At TRP Polymer Solutions, we work closely with our customers to accurately match the unique operating conditions of your application and match them with the best-suited elastomer. We carefully consider the full operating environment rather than focusing on a single performance metric. Whether it’s a well-established elastomer or we develop a bespoke material through our rubber moulding design for you, you can trust our custom rubber seals to deliver on performance where it matters most.

To find out more about our high-temperature O-rings, contact TRP Polymer Solutions today, and our expert engineers can discuss how we can provide you with your ideal sealing solution.

Emily HD 4 Aug 2026 • 4 min read

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