Advantages of Stainless Steel Plumbing Systems

• General corrosion rates in drinking waters are negligible and a corrosion allowance is unnecessary
• Not easily damaged by use in public areas
• Galvanically compatible with copper alloy fittings
• Extremely low levels of metal leaching
• 100% recyclable

Frequently Asked Questions of Stainless Steel Products

• What is stainless steel?

Stainless steel, compared to typical steel, is a general class of metal alloys that contains lower levels of iron and higher levels of chromium, vanadium, etc. The actual percent of the various elements yield different physical properties.

• Why do people use stainless steel products with drinking water systems?

In general, stainless steels are quite hard, tough, and corrosion resistant in comparison to some other materials used in drinking water applications.

• Are all stainless steel products compliant with NSF Standard 61?

No. Only products that are certified to NSF/ANSI Standard 61 can be assumed to meet the requirements of NSF/ANSI Standard 61. Certification to NSF/ANSI Standard 61 includes product testing and production location auditing to ensure ongoing compliance with the health based requirements of NSF 61. This includes testing products on an annual basis, by exposing them to different formulated waters (typically at pH 5, pH 8 and pH 10) and testing for regulated metals such as antimony, arsenic, barium, cadmium, chromium (including chromium VI), copper, lead, mercury, selenium, thallium, and nickel, as well as any other inorganic and organic leachate concerns that may derive from cutting oils, lubricants, process aids, welding, machining, and other forming by-products. The certification process also includes annual unannounced inspections of the manufacturing facility to verify that the manufacturer is making the product using the same raw materials, material suppliers and production process as the products that are tested.

• I thought because stainless steel was listed in Annex C of NSF 61 that all stainless products
  meet the requirements of the standard?

Annex C of NSF 61 provides a list of materials that have been extensively tested under certain conditions, which then can reduce the amount of testing that NSF needs to perform when certifying products to NSF 61. For example several grades of stainless steel have been listed under Annex C at specific surface area to volume ratios and at certain temperatures (23°C and 30°C). When product manufacturers use these materials in their products under these conditions, NSF may not have to do as much testing as we would if they were using other materials. However NSF would still need to audit the manufacturing facility to verify that these materials are being used in certified products, and testing would be required if other materials are in the products, or if the stainless steel is being used at higher temperatures such as domestic (60°C) or commercial (82°C) hot water.

• I need NSF Standard 61 Certified stainless steel pipe and fittings. Where do I find them?

Use the NSF web-based Standard 61 Certified Potable Water System search engine. From the NSF website you may choose from many search criteria such as:

Manufacturer name, if you know the maker of the product.
Product trade name, if you know the tradename or model number, etc.
Manufacturing location, if you seek product from a certain country, state, etc.
Product type, if you need a particular item like pipe, valve, fitting, pump, etc.
Material type, if you need a specific material such as SS, PVC, PE, Cu, brass, etc.

• If I can't find the specific company/product type I seek, what should I do?

Contact NSF staff for assistance. Have details of your target products and preferred suppliers. NSF staff may be able to help you find the NSF 61 Certified products you seek. NSF can also help you by networking with your preferred suppliers and rapidly arranging the appropriate evaluation of products you need to meet bid specifications and drinking water safety requirements.

• Why do companies get NSF Standard 61 Certified for stainless steel products?

Most US States and Canadian Provinces have regulations or policies that require public drinking water system components to comply or be certified to NSF Standard 61. In addition most of the plumbing codes across the US also require products to be certified to NSF 61. While enforcement of these requirements varies greatly by region, these requirements have resulted in a growing number of specifications for NSF 61 for stainless steel and other potable water products.

Make sure the products you buy are NSF Certified!

If you have additional questions relating to NSF/ANSI Standard 61 and stainless steel or NSF's certification services, contact Dave Purkiss at 734-827-6855 or purkiss@nsf.org.