Researchers at Purdue University have...
Making the Right Choice
Note: Article refers to two tables which can be viewed in the article PDF.
Product standards provide a valuable structure and support to any product category. They are used universally to establish a single set of methods and criteria by which products are evaluated, leveling the playing field for the industry, enabling a single specification of compliance by regulators and other specifiers, and simplifying the purchasing decision of buyers. All of these critical elements are certainly true of the drinking water industry where standards have existed for more than three decades.
Most of the NSF Standards are widely applied and understood by the industry; however, it is easy to confuse the subtle differences between some, and even easier yet to be confused by the requirements of individual standards. Table 1 is a quick reference to the eight American National Standards that are used today throughout the drinking water industry. Each of these is developed through a consensus process facilitated by NSF, involving representation from the regulatory, user and industry communities. They are the most comprehensive set of standards in the world for drinking water products, and set a very high bar to ensure product safety and public health protection.
The Standards differ primarily by product type and by the type of product evaluation. Six of the eight are applied to the point-of-use (POU) and point-of-entry (POE) drinking water treatment industry. These include Standards 42, 44, 53, 55, 58 and 62. In all of these, the water treatment systems must undergo demonstration of compliance with material safety, structural integrity (plumbed-in systems only) and product literature. Finally, they must be certified for at least one contaminant reduction claim, of which there are many options they can select from (see Table 2 on page 8).
The remaining two, Standards 60 and 61, are applied to all other products that come in contact with drinking water, whether simply for distribution or treatment. In the case of these, material safety is the only product evaluation performed.
The NSF Standards are in a constant state of change and expansion, keeping pace with the evolving needs of the marketplace. There are several new areas under development, with completion expected in 2004/2005. They include a new standard for shower filters, several new standards for bacteria and virus reduction, and new contaminant reduction claims under existing standards for perchlorate and arsenic (total and trivalent arsenic).
Shower Filters. NSF Standard 177
will apply to shower filters only. The Standard will carry the same basic template as the other NSF POU/POE standards, including structural integrity testing, requirements for product literature and demonstration of material safety. Material safety will be limited to a wetted parts list review, prohibiting lead as an ingredient and solvent bonding as a manufacturing technique. No extraction test will be required. With respect to contaminant reduction claims, there
will be a single, mandatory claim for
free available chlorine. Additional, optional claims are expected to be
added in the future.
Microbiological Treatment. Bacteria
and virus reduction claims are being developed for several product technologies, all of which will fall under
a new set of NSF Standards with the designation of 240. These will also incorporate the current requirements
for cyst reduction, making the standards comprehensive in their requirements
for microbial treatment claims. Mechanical and halogen treatment technology standards are the furthest along in development.
New Chemical Reduction Claims. Two new contaminant reduction claims are expected to be available soon. They include perchlorate for non-reverse osmosis systems, including anion exchange resins, and arsenic. Both of these are already addressed to some degree by the NSF POU/POE Standards. In the case of perchlorate, this claim already exists for reverse osmosis treatment technologies as covered under NSF/ANSI Standard 58. The expansion will include the same under NSF/ANSI Standard 53. In the case of arsenic,
the pentavalent form of arsenic (As V,
As+5) already exists under both Standards 53 and 58. The expansion will include
a new section under Standard 53 for trivalent arsenic (As III, As+3), and by default will include a total arsenic claim for those able to reduce both the
trivalent and pentavalent forms.