By David Bentley

The ANSI/NSF Drinking Water Treatment Unit (DWTU) Standards address many aspects of product design and function. Most people think of design requirements, structural integrity testing, material extraction testing, contaminant reduction testing, and general performance testing when they think of the requirements for these standards. Still, there’s another set of requirements that must be addressed for products to conform to these standards—the requirements for product literature.

Consumer education
Drinking water treatment products are technically sophisticated. They use many different technologies to accomplish their purpose of treating water. Many times, treated water is difficult to distinguish from untreated water by visual or olfactory methods. Because of the complexity of treatment and the fact there may be no obvious result of treatment, the process and products can be difficult for consumers to understand.

For this reason, product literature that helps to explain the capabilities and limitations of the products is required. The literature allows consumers to understand the product they have purchased or are considering for purchase. It also allows them to compare products as the purchase decision is being considered.

Four pieces of literature
The DWTU standards require four separate and distinct pieces of product literature:

  1. The installation and operation manual (to be included with each system) shall include, along with other information, the complete detailed instructions for installation, operation and maintenance of the system.
  2. The system data plate (to be affixed on each system in a readily accessible area) shall include, along with other information, the model number of the system and the replacement cartridge that’s to be used in the system.
  3. The replacement component packaging (to be included with each replacement component) shall include, along with other information, the name of the component and the system(s) that it may be used in.
  4. The performance data sheet that’s available to potential customer from the manufacturer shall include, along with other information, the system model number and test data for claims that have been validated for the system.

Certain aspects of the requirements for this literature are very “common sense” items, i.e., the model number of the product must be included and so on. But other aspects are not so obvious and sometimes lead to confusion for manufacturers attempting to conform to these requirements. A discussion and explanation of these more complicated aspects of product literature follows, which serves as a “self help” guide to development of product literature.

Helpful hints
“Certificación independiente” and “certifié indépendamment” both translate to “independently certified.” These phrases, included within the new certification mark, may be used on product packaging and literature. The use of this new mark is just one of the new requirements that may be applicable to a company when preparing literature for certified products. Section 7 in the current DWTU standards contains the requirements for product literature.

All of the DWTU Standards–42, 44, 53, 55, 58 and 62–require that you provide a use and care manual, a data plate and performance data sheet literature for the product. Standards 42, 53 and 55 also include requirements for replacement component literature.

Questions arise when standards require various statements relating to the product applications. When the standards reference a requirement in quotes, this requires that the statement be referenced, verbatim in product literature, as stated in the standard. Examples of this type of statement are the carbon caution statement in Standards 42, 53 and 58. This states, “Do not use with water that is microbiologically unsafe or of unknown quality, without adequate disinfection before or after the system.” The cyst portion of this statement, as referenced in Standards 53 and 58, states, “Systems certified for cyst reduction may be used on disinfected water that may contain filterable cysts.” In Standard 58, depending on the water supply pressure, this would apply to the nitrate/nitrite statement. This states, “This system is acceptable for treatment of influent concentrations of no more than 27 mg/L (milligrams per liter) nitrate and 3 mg/L nitrite in combination measured as N and is certified for nitrate/nitrite reduction only for water supplies with a pressure of XX or greater,” where “XX” will reference either 20 or 40 pounds per square inch gauge (psig).

The standards also reference statements needed in literature that aren’t in quotes. Though required, they don’t need to be verbatim as stated in the standard. When preparing these statements, it’s important to remember the intent of the statement should be included in product literature. These statements may be crafted to meet the manufacturer’s need. Examples of these are the fact that all of the DWTU standards require a statement relating to user responsibility and parts/service availability. Examples could be, “The filter cartridge used with this system has a limited service life. Changes in taste and/or flow indicate that the filter cartridge should be replaced” and “For replacement parts, contact your nearest retailer or call XXX for your nearest retailer.”

Standard 44 requires a statement concerning the noted efficiency as determined by the laboratory test in relation to what may occur for the end-user based on their individual water characteristics. Standard 55 requires a statement regarding the statement of application—whether it’s a Class A or Class B system. A Class A system is validated to provide a UV dose—at a wavelength of 254 nanometers of at least 40 milliJoules per square centimeters (mJ/cm[²])—and is required to included a monitor. The Class A system may be viewed as a purifier. The Class B system is validated to provide a UV dose—at a wavelength of 254 nanometers of at least 16 mJ/cm[²]—at 70 percent of the UV lamp’s normal output. The Class B system is designed to inactivate nuisance microorganisms that naturally occur in drinking water. With the recent clarification of the arsenic reduction claim in Standards 53 and 58, to include pentavalent arsenic (As-V), comes the inclusion of the Arsenic Facts section of the performance data sheet. Again, it’s important to remember the intent of these statements be included in the product literature where necessary.

The requirements within the performance data sheet have also changed recently. Where test data grids are required, the information that needs to be included within this grid has been reduced. One will need to include the substance and influent challenge within this grid and, based on the validated claims, the reduction requirement and/or the maximum permissible product water concentration. These are the minimum requirements for this grid; and it’s not to say the previously required average influent/effluent and minimum/maximum percent reduction may no longer be included. This information may still be included within this grid; it’s just in addition to the above referenced minimum requirements.

The subject of VOCs
During the recent Industry Forum and Joint Committee meetings at NSF in October, discussions were held to determine whether it would be acceptable for manufacturers to make additional volatile organic compounds (VOC) reduction claims on their product literature. It was determined that based on the VOC surrogate test that a manufacturer has successfully passed, it would be acceptable to make these claims. For example, additional claims such as Atrazine and 2,4-D may be made on product literature. Prior to including this information on literature, however, it will need to be officially balloted by the Joint Committee and approved and then approved again by the Council of Public Health Consultants.

A favorite selling point for manufacturers is to state the percent reductions of specific contaminants on the product literature for their product. The most common words most frequently associated with validated product claims are “reduces” and “removes.” When using “reduces,” there are no caveats associated with this word. As an example: “Reduces lead” would be an acceptable statement. When using “removes,” the caveat associated with this word is that a specific percent reduction will need to be referenced. For example, “Removes 98 percent of lead” would be an acceptable statement. The only instance where “removes” would be allowed for use, without a specific percent reduction, is in the case of a cyst reduction statement. “Removes cysts” would be an acceptable statement. The basis for this allowance is the fact that to make this claim, the manufacturer will need to meet, at a minimum, a 99.95 percent reduction for this test.

Do you think preparing literature for certified products is a hassle? Using these aforementioned guidelines, along with the requirements of Section 7 in the ANSI/NSF standards, can make a literature review more hassle-free.

About the author
David Bentley is a group leader in the Drinking Water Treatment Unit Program at NSF International, of Ann Arbor, Mich. He has been with the water program for 10 years. Bentley can be contacted at (800) 673-6275, (734) 769-0109 (fax) or email:


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