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Is hot-dip galvanizing NSF 61 certified for Potable Water?

In the mid-1980s Congress passed the Clean Water Act, which includes the Drinking Water Standard. This standard requires any material or coating in contact with drinking water to be tested according to National Sanitation Foundation (NSF) Standard 61: Drinking Water Systems Components: Health Effects. As a result, only galvanizers audited and approved by the NSF have the authority to galvanize products for use with potable water. 

However, NSF-61 certification is product based and not galvanizer based. Any customer needing this certification must contact NSF directly to start the certification process. This process requires testing of the final product in addition to an evaluation of the galvanizer if they are not already certified to galvanize items for a specific product or end-use. Evaluation of the galvanizer typically involves an audit, a sample of the zinc bath, and a finished galvanized test article. Galvanizers using High Grade (HG) or Special High Grade (SHG) in the zinc bath should not run into issues regarding the chemical composition testing for lead. However, there are issues with high zinc content in one of the qualification tests when evaluating pipes less than three inches in diameter.

Upon completion of the certification process, the galvanizer is NSF 61 certified for a specific product such as water distribution pipe or water storage tanks. However, the galvanizer cannot claim they are simply "NSF 61 certified". They must qualify that statement with what products and/or end-uses they have been audited and approved by NSF 61 for, such as “we are NSF-61 certified for water storage tanks”.

An example below is provided to clarify the difference regarding the “product based” NSF 61 certification and certification of the galvanizer: 

If a galvanizing plant was successfully audited by NSF in the past for Customer A’s galvanized water pipes, Customer B cannot simply galvanize their own water pipes using the same galvanizer and label it "NSF-61 certified". Customer B still has to contact NSF directly to begin the NSF 61 certification process for their product even though NSF knows the galvanizing plant is “certified”. However, if the galvanizer was already certified for a previous customer, the NSF 61 certification process becomes quicker/easier for Customer B because NSF may or may not require a re-audit of the galvanizing plant to certify the product.

For more information, NSF maintains a list of galvanizers that have obtained an NSF certification. This page also contains a list of all NSF certified products that have been hot-dip galvanized:

·  NSF list of certified galvanized products and galvanizers

·  NSF/ANSI/CAN 61 Certification Information 

Comments

Martín Fernández/ Espina S.A.

I have recently downloaded NSF 61 from NSF web, because my company is building a drinking water treatment plant in URUGUAY. One possible coating for the pipes is HDG (hot dip galvanize), so my company is looking for certified HDG providers in China. Can NSF send a list of HDG providers certified in China?

Alana Fossa (AGA)

Hi Martin, NSF maintains a list of all approved galvanizers on their website through the link I provided in this article. However, no galvanizer will already be certified for your exact product design. If there are no galvanizers from China on the NSF list already approved to galvanize your product, then you must assist your local galvanizer in applying for certification via NSF: http://www.nsf.org/services/by-industry/water-wastewater/municipal-water-treatment/nsf-ansi-can-standard-61

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