EPDM vs Viton (FKM) for Chemical IBC Seals
This FAQ EPDM or Viton contains frequently asked questions about EPDM or Viton seals that are used in the VARIBOX. This FAQ explains seals used in the VARIBOX and their materials. It also helps to choose the correct material for your application. In the end, you will find a general guidance table.
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What are seals?
You will find seals in the screw cap, combi vent, extractor tubes, and level sensors. Seals ensure the leak tightness of closures, so chemicals and fumes stay inside. The VARIBOX can be equipped either with EPDM seals or with Viton seals.
EPDM
What is EPDM?
EPDM is a material used for the seals (gaskets) in many VARIBOX components. EPDM is an elastomer and is short for Ethylene Propylene Diene Monomer, a type of synthetic rubber.
How resistant is EPDM?
EPDM has good resistance to many chemical products like detergents, caustic potash solutions, sodium hydroxide solutions, and many other diluted acids and chemicals. It is not resistant to most hydrocarbons, such as oils, kerosene, gasoline, and many solvents. EPDM is resistant to steam and ozone.
Viton
What is Viton?
Viton is a material used for the seals (gaskets) in many VARIBOX components. Viton® is a registered trademark of The Chemours Company and is an FKM material. This is a fluoroelastomer, another type of synthetic rubber. When a VARIBOX is equipped with Viton, the seals in the CDS extractor tube will be made of Aflas®. This is TFE/P, another fluoroelastomer, from the Asahi Glass Ltd
How resistant is Viton?
Unlike EPDM, Viton has good resistance to oils, fuels, lubricants, and most mineral acids. It is resistant to most chemicals, but not too for example Acetic acid, Ammonia, Caustic soda, Formic acid, and Potassium hydroxide.
EPDM vs Viton: which seal should you choose?
| Selection point | EPDM | Viton (FKM) |
|---|---|---|
| Typical strengths | Many detergents, caustic solutions, steam and ozone | Oils, fuels, lubricants and many mineral acids |
| Typical limitations | Many hydrocarbons, fuels, oils and solvents | Some chemicals including acetic acid, ammonia, caustic soda, formic acid and potassium hydroxide |
| Final selection | Confirm the exact chemical, concentration, temperature and complete wetted configuration before use. | |
Is Viton better than EPDM?
This question cannot be answered in general: in many cases, both materials will be resistant to the chemical product in the VARIBOX. But some chemicals are not compatible with EPDM, and Viton is the better choice. And some chemicals are not compatible with Viton and EPDM is the better choice.
How do I choose the correct sealing material?
General guidance on regularly filled chemical products is listed in the table below. Check the resistance of these seals against the product that you want to fill into the VARIBOX. Some chemical products are causing strong deterioration of EPDM as well as Viton, like Hydrofluoric acid and Nitric acid in high concentrations. With these chemicals, we advise you to choose Viton as it outperforms EPDM. Regularly inspect the quality of the seals. Especially at elevated temperatures the seals may deteriorate quickly and need to be replaced.
Couldn’t find your answer in the FAQ EPDM or Viton?
We know that the safe and reusable VARIBOX IBCs are being used for many different applications in many different markets. Therefore it could be that your question/answer is not included in FAQ EPDM or Viton. If so, please contact our Customer Service, they are glad to help further.