By Jane Wilson, M.P.H.
The first meeting of the NSF International Drinking Water Treatment Unit (DWTU) Material Safety Task Group took place in April 2000. The task group was formed in the fall of 1999 with volunteers from NSF joint committees on DWTUs and Drinking Water Additives (DWA), and other interested parties such as the Water Quality Association (WQA). Its formation was supported by the two joint committees for evaluation of whether ANSI/NSF 61 Drinking Water System Components–Health Effects should be used as the material safety standard for the DWTU industry. Both joint committees have agreed in principle that ANSI/NSF 61 (Standard 61) should be considered as an alternative to the material safety requirements in the NSF DWTU product standards.
The goal of the task group is to make recommendations to the two joint committees regarding the use of Standard 61 as the material safety standard for the DWTU industry and to propose any revisions to Standard 61 and the NSF DWTU standards that would be necessary.
Evaluation of point-of-use/point-of-entry (POU/POE) DWTU devices is currently excluded from the scope of Standard 61. During the initial development of Standard 61, other ANSI/NSF standards that addressed materials safety for DWTU devices were already in use, and a rationale for using Standard 61 instead was not apparent. Since its initial adoption in 1988, Standard 61 has become widely recognized in the drinking water industry, particularly by the regulatory community. It’s cited in the major plumbing codes and 43 of 49 states that have primacy over their drinking water programs require compliance to Standard 61 by regulation or policy for drinking water contact products installed or used in their state.1 Because of Standard 61’s widespread recognition as the material safety standard for all other drinking water contact products, the DWTU industry has now recognized the advantage of utilizing a single standard to address material safety.
At its first meeting, the task group reached consensus on several key questions that will determine the path forward. First, it agreed that—if used—NSF 61 would eventually be the one standard for evaluating material safety for both DWTU systems and components. Recognizing that many products have already been evaluated to the existing DWTU material safety requirements, transitioning to the use of Standard 61 as the sole material safety standard will require a lengthy implementation period. The task group will also consider the incorporation of elements of the current DWTU material safety protocol into Standard 61 where appropriate to facilitate this transition.
Secondly, the task group identified two routes for use of Standard 61 as the DWTU material safety standard. Manufacturers of DWTU components could have their products tested, and assemblers could subsequently select previously tested components to construct their system(s). Many components can be tested to existing protocols in Standard 61 without revisions to the standard being necessary, such as tubing and gasket components. Alternately, complete systems could be tested by an assembler or a manufacturer, as is currently done under the DWTU standards. The task group determined the existing Standard 61 POU/POE product protocols aren’t appropriate for DWTU system evaluation and would require some additional provisions.
Task group participants also decided that complete systems tested for material safety under Standard 61 will still require evaluation of any associated performance claims and evaluation of design and construction, as is currently required under NSF’s DWTU standards. DWTU components could be tested for Standard 61 compliance alone since the current DWTU standards don’t require evaluation of performance claims and of design and construction for components. Marking requirements for components will need careful deliberation to avoid the misinterpretation that a system containing a single component compliant to Standard 61 fully meets the material safety requirements, or has been verified for performance and design and construction.
The current material safety requirements of the DWTU standards as compared to the requirements of Standard 61 were also examined in great detail by the task group. Six areas were compared between the two existing sets of requirements: information requirements; selection of analytical parameters; exposure of samples; analytical methods; normalization—estimation of at-the-tap exposure to extractants, and evaluation criteria. The two systems were determined to be alike in the areas of information requirements, selection of analytical parameters and analytical methods, but were very different in requirements for exposure of samples, normalization and evaluation criteria. These latter three areas will be the focus of future deliberations of the task group.
In moving forward, the task group has decided to first address development of a protocol for POE units. Review of the current Standard 61 requirements for non-DWTU POE devices (such as a water meter, inline control valve, etc.) suggests that relatively few changes may be needed to achieve an appropriate protocol for the DWTU POE devices. Challenges such as how to evaluate products that utilize replaceable media will be addressed by the task group. It was agreed that as much of the existing language in Standard 61 would be used as possible to expedite the process of developing the requirements for DWTU evaluation. Development of a protocol for POU units is anticipated to require more effort, since the current evaluation procedure for non-DWTU POU devices (such as a faucet, icemaker, refrigerator glass filler, etc.) in Standard 61 was designed primarily to evaluate faucet products only.
A follow-up meeting of the task group is anticipated for July 2000, at which time a draft protocol for DWTU POE devices is expected to undergo review by the participants. This effort to evaluate Standard 61 as the material safety standard for the DWTU industry is receiving enthusiastic support, and NSF International looks forward to providing the consensus process through which the DWTU industry can achieve this goal.
- ASDWA Survey on State Adoption of ANSI/NSF Standards 60/61, 8th ed., January 2000, Association of State Drinking Water Administrators, Washington DC.
About the author
Jane Wilson is senior project manager for drinking water standards in the Standards Department at NSF International. Her master’s degree in public health is from the University of Michigan and she’s been involved with Standard 61 for almost 10 years. NSF can be reached at (800) 673-6275.