By Rick Andrew
The NSF/ANSI Standards have historically addressed material safety for most products under NSF/ANSI 61, whereas material safety for point of entry (POE) and point of use (POU) products has been covered by the NSF/ANSI DWTU Standards. The main reason for this is actually historical—the NSF/ANSI DWTU Standards were developed first and covered material safety, so when NSF/ANSI 61 was developed in the mid 1980s to deal with material safety in the water distribution system from the wellhead to the tap, POE and POU systems were excluded from the scope.
With new revisions of these standards having just published or about to publish, this gap is now being bridged with respect to POE systems. Let’s explore how this was accomplished and what the new revisions to these standards mean for POE systems, components and media.
A cross reference is established
The following language has been or is being added to Section 4 of all of the NSF/ANSI DWTU Standards: POE drinking water treatment units shall conform to the protocol and criteria in NSF/ANSI 61. POU drinking water treatment units shall conform to the protocol and criteria in this section.
Essentially, this means that material safety for POE systems must be addressed according to NSF/ANSI 61, whether the product is eventually certified to Standard 61 or to the appropriate DWTU Standard.
Changes to NSF/ANSI 61
In order to accommodate the addition of POE systems and components to NSF/ANSI 61, several revisions were required; highlights of these are:
- Removal of the exclusion of POE drinking water treatment devices and creation of new exposure protocols for POE media, non-media components and systems based on a combination of aspects from NSF 61 and the DWTU materials safety exposure protocol. See Figure 1 for details on these protocols.
- Addition of a requirement to section 10 that clarifies for consumers in the product literature, information and instructions that POE drinking water treatment unit systems certified under NSF/ANSI 61 for materials safety may not necessarily be likewise certified for contaminant reduction or structural integrity performance.
Comparison of test protocols
Previously, POE systems were tested according to the NSF/ANSI DWTU Standards. The protocols for POE and POE systems were identical. For reference, Figure 2 includes details regarding the current POU/former POE exposure protocol.
The chemical analysis and toxicological interpretation of the test results of all of the protocols is very similar. Essentially, analytical scans are selected based on a review of each and every material in contact with drinking water present in the product being evaluated. The exposure water is chemically analyzed for all of these scans after it has been exposed to the product.
Once all of the analytical data has been assembled, the results are reviewed to determine if any contaminants were detected at toxicologically significant concentrations. If not, then the product conforms to the requirements of the standard.
Two committees working together
Accomplishing these changes to the NSF/ANSI DWTU Standards and NSF/ANSI 61 required the concerted efforts of two different joint committees on standards. It is no small feat to initiate change within one joint committee, let alone harmonizing that effort between two of them. The successful end result is a testament to the open mindedness and persistent efforts of these two all-volunteer committees consisting of representative experts from the manufacturing, regulatory and product user interest areas.
Advantages for manufacturers
Manufacturers now have the ability to certify POE systems and components to Standard 61 and/or the NSF/ANSI DWTU Standards. The real value of this option is in cases where certain types of POE systems do not fall under the NSF/ANSI DWTU Standards, such as chlorinators and other chemical feed systems. These systems and components can now be certified to NSF/ANSI 61, whereas previously they were excluded.
There are also some new options for POE components. For example, previously, activated carbon could be certified for municipal use to Standard 61 or for DWTU use to Standard 42. Now, in addition to these options, activated carbon can be certified to Standard 61 or Standard 42 for POE use. The same holds true for ion exchange resins and other media. Furthermore, components such as filter housings can now be certified explicitly for POE or for POU applications.
Other possibilities include dual certifications for POE products to the NSF/ANSI DWTU Standards and NSF/ANSI 61, with no need to conduct two different extraction tests. In this way, products can demonstrate conformance to NSF/ANSI 61 where required and also to the DWTU Standards to meet the demands of other markets and customer specifications.
Essentially, the gap between the NSF/ANSI DWTU Standards and NSF/ANSI 61 has now been bridged. The world of municipal and POE products has grown smaller. Building this bridge offers additional flexibility, buyer acceptance and certification options to manufacturers across market sectors with condensed testing requirements—a win/win for all involved.
About the author
Rick Andrew is the Operations Manager of the NSF Drinking Water Treatment Units Program. Prior to joining NSF, his previous experience was in the area of analytical and environmental chemistry consulting. Andrew has a Bachelor’s Degree in chemistry and an MBA from the University of Michigan. He can be reached at 1-800-NSF-MARK or email: [email protected].