We find that many customers are confused about what exactly the NSF/ANSI Standard 61 certification means and what chemicals are covered under that certification. It’s important that all components in water treatment meet the correct standards to ensure dangerous toxins aren’t leached. Let’s explore what NSF/ANSI Standard 61 covers and how to make sure your chemical storage tank system meets the necessary requirements.
What is NSF/ANSI Standard 61?
NSF/ANSI Standard 61 (NSF-61) is a set of national standards that relates to water treatment and establishes stringent requirements for the control of equipment that comes in contact with either potable water or products that support the production of potable water. The tests vary from a basic cold water test using water at different pH levels, to the more challenging chemical certification. In all cases the equipment is tested before and after exposure to a given fluid to determine whether anything has been leached out or extracted from the equipment. NSF-61 was developed by the National Sanitation Foundation (NSF), a global independent public health and environmental organization, and the American National Standards Institute (ANSI), which oversees the consensus for developing standards for manufacturing and procedures in the United States.
How Do I Know if My System Is Certified?
Depending on the certification level, NSF-61 can apply to just potable water or a variety of chemicals and there varying levels of concentration. Because there is some ambiguity, manufacturers may not convey the appropriate certification level for their product or customers may not buy the appropriate product for their application. Manufacturers may list that their products as NSF-61 certified, but it may only apply to potable water and not chemicals.
Most manufacturers only test pH 5, pH 8 and pH 10 exposure waters defined in the standard. This helps account for the variety of waters found across North America, but does not predict leaching of materials in chemical storage tanks. In order to confirm that a product meets the correct standards for your application visit the NSF website for a complete list of components by manufacturer along with the chemicals for which the components are certified. Next to the chemical name, you will see a percentage that denotes the concentration for which the product is certified. For example, you may see a storage tank with sulfuric acid ≤ 98%, which means that the tank is certified to store up to a 98% concentration of sulfuric acid.
Even smaller parts of your system, like gaskets, should be considered. For example, the gaskets used in the storage of sodium hypochlorite, bleach, are commonly made of Viton. However, standard latharge Viton is cured with lead and will not pass the NSF-61 certification process. A sodium hypochlorite requiring the NSF-61 certification must use either EPDM or Viton GF. Although Viton GF is more expensive, it is a purer version of Viton, which is NSF-61 certified. When selecting equipment it’s very important to make sure all materials meet NSF-61 standards for potable water or chemical storage.