O-Rings & Seals for Water Purification & Filtration Products

There are many health benefits to drinking filtered water instead of tap water. Some of the many benefits are cleaner tasting water; better tasting drinks and food; healthier because of less contaminants; and less mineral and lime deposits that build up on faucets, shower heads, and tubs. For these and many other reasons water filters have become extremely popular.

Most water filters are designed to filter municipal drinking water, i.e. tap water, which the components of the filter, such as the rubber O-rings and seals, will possibly come in contact with chloramines that are formed during the disinfecting treatment. As we learned earlier, chloramines can deteriorate certain rubber compounds.

Nitrile and EPDM with a sulfur cure are the most common rubber materials used in water filtration. Nitrile rubber is one of most common elastomers used in O-rings and seals. It offers good physical properties and temperature range at a relatively low cost compared to other types elastomers. Nitrile rubber has a broad temperature range from -40°C [-40°F] to +100°C [+212°F] and also works well with most oils and greases.

EPDM rubber offers good low temperature flexibility, high tensile strength, high tear and abrasion resistance and excellent resistance to ozone, water and oxidation. EPDM’s temperature ranges from -55°C [-67°F] to +125°C [+257°F] but is not compatible with most oils and greases, but it’s the recommended material for use with water. A Peroxide Cured EPDM rubber compound is recommended for chloramine resistance.

NSF61 certified Nitrile and EPDM compounds are available at Satori Seal. NSF International is an international organization that tests and certifies products as safe. Their standards are applied in many industries. In the rubber industry one of the more common standards is “NSF Standard 61: Drinking Water System Components – Health Effects”. NSF Standard 61 sets limits for the amount of chemicals permitted to leach into drinking water from the materials used in water transmission and distribution. Any supplier of drinking water knows their products must be be certified to NSF/ANSI Standard 61 (“NSF 61”).