Municipal Water System O-Rings & Seals

Municipal water is water that is distributed to homes and business’ through a network of pipes by a municipal water company. Municipal water comes from lakes, rivers and reservoirs. Free standing water that is exposed to sunlight and air is more likely to become contaminated with disease-causing germs. This water is then treated at a water treatment plant before it is tested for EPA compliance. Municipal water companies chlorine and/or chloramine treat their water to disinfect against disease-causing bacteria, viruses and protozoans. Chloramine is less volatile than chlorine and stays in the water longer. This helps disinfect the water pipes leading to and in your home or business. Chloramines have an adverse affect on some type of rubber like sulfur cured Nitrile and EPDM causing them to deteriorate rapidly. A Peroxide Cured EPDM rubber compound is recommended for chloramine resistance.

According to the International Bottled Water Association, in the United States, less than 1% of municipal water is used for consumption. Most of it is used for bathing, cooking, cleaning, and irrigation. Household faucets, shower heads, toilet valves, pool filtration systems, irrigation valves and sprinklers all contain rubber seals and can be susceptible to chloramine attack depending on the amount of exposure to the water.

Nitrile and EPDM with a sulfur cure are the most common rubber materials used in water. 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”).