Testing Elastomer Materials for Potable Water Systems

Mar 01, 2016 Oil Seals | Gaskets | Materials

Potable water systems are designed to transport drinking water over many miles of pipelines, pumps, and valves to reach your home. To ensure that the water is always fit for consumption, all the transport, storage, and mechanical devices need to be constructed from materials that are not hazardous, and will not affect the water.

When it comes to seal water systems, elastomers are the first choice for manufacturers to meet government and federal requirements. Popular materials include:

Styrene Butadiene (SBR)
Chloroprene (Neoprene)
Acrylonitrile Butadiene Rubbers (NBR)
Ethylene Propylene Diene Rubber (EPDM)

However, before they are used in the seal and gasket manufacturing process, they need to meet industry standards and regulations.

Testing Procedures for Elastomers used in Seal Water Systems

The seals and gaskets made from these elastomers have to adhere to NSF ANSI Standard 61. This standard is related to drinking system components. As stated by the NSF, Standard 61 was created to “establish minimum requirements for the control of potential adverse human health effects from products that contact drinking water.”

The elastomers have to undergo tests to ensure that they meet regulations within the standard. Generally, these tests are performed using Inductively Coupled Plasma/Mass Spectroscopy equipment (ICP/MS).

Toxicology Calculation: Toxicology tests are performed on the materials to check if they meet the criteria laid down in Annex D and E of NSF/ANSI Standard 61. The tests are performed to specifically test the level of contamination in each material. In Annex D and E, the test results are compared with the Total Allowable Concentration (TAC). Combining both annex tables, the TAC ranges from 0.01 to 9 mg. The contamination levels need to be less than or within this value range. If the elastomer meets this criteria, then it is certified by NSF and ANSI.

Follow-up Testing: Post certification, the materials are listed by the NSF and reviewed annually. NSF auditors make unannounced inspections to ensure that the certified products continue to meet authorized formulations.

Processes Performed on Test Failure

When a product with a particular elastomer fails the annual test, the manufacturer is notified by the NSF, and he is forced to stop any shipments of the product. The manufacturing facility is then inspected by the NSF auditor to find the cause of the problem. Once the problem has been solved, the manufacturer can send the product for certification again.

It is important for seal manufacturers to understand these points. The success, use, and longevity of seal water systems depends entirely on the NSF/ANSI certification. Ensuring that the elastomers meet regulated contamination levels will ensure that the drinking water supplied to the public will be harmless and healthy.