By Thomas J. Spoden, CWS

Product certification usually involves an independent, third-party evaluation to ensure it meets industry standards. These standards have been developed over many years with input from industry, health regulators and certifiers to ensure all viewpoints are taken into consideration. In fact, the Drinking Water Treatment Unit (DWTU) standards were first developed due to requests by industry to elevate themselves and differentiate products that were effective and safe from those that were not. Product certification, therefore, provides assurances to consumers and health regulators that a product is in conformance with the safety requirements in the standards and can perform as it claims.

The process of product certification can be exhausting. All certifiers attempt to make the procedure as painless as possible, but there is no getting around that it requires a sizable investment of time and resources from the applicant. Due to the investment up front, some in the industry feel product certification is finished after the initial product evaluation has been completed. Product certification is not a one-time deal, however. It is more accurate to look at product certification as a continuous process that requires monitoring and updating while items change over time. The process by which products change gradually over time is known as manufacturing creep. Combating this process is a critical factor in effective product certification evaluations. Without ongoing assurances that products continue to meet the requirements of the standards over time, product certification loses all its long-term value.

The three pillars
Certification systems are supported by three pillars that are all essential to maintaining credibility and effectiveness. The first is testing, which not only ensures a product performs as advertised, but also meets safety standards for consumers and their property. The second pillar is a literature review done by the certification body. This review ensures the manuals, data plates, packaging and other printed materials are not only in compliance with the standards, but also do not make claims unsupported by testing. The final pillar is an audit of the manufacturing facility. This facility assessment verifies the product is manufactured with the same suppliers and materials that were tested, the maintenance of a required quality-control system and proper labeling of the product.

These three pillars are self-reinforcing, meaning each relies upon the other for validation and support. As an example, the literature is approved by the certification body, but the audit confirms the approved literature is actually used. As another example, an auditor finds a new media is being used, but it is testing that confirms whether or not this new media actually works and is compliant with the material safety section of the applicable standard. Each pillar is necessary and without any one of them, the entire structure falls apart.

The initial review of a product leans heavily on all three of these pillars, but it is still necessary to continue to ensure the product that is made tomorrow remains the same as the one certified today, otherwise the certification has no value. Because of that, certifiers conduct regular monitoring of the marketplace to ensure products being sold are the same as the ones initially reviewed and tested. This involves annual audits and periodic retesting of products, which can result in updates to the literature based on the new information. There is very little dispute over audits and literature as both of those are relatively straightforward to understand; however, retesting of a product can be a controversial topic since some manufacturers may assert that they have made no product changes since the previous certification project.

Retesting intervals
Retesting of products is typically done at regular intervals to ensure products continue to meet the requirements of the standard. Most of us recognize that if a product changes, it needs to be re-evaluated and potentially retested, but would it be better to eliminate the retesting portion of certification programs if a product appears not to change? The answer to that question is a resounding no. Retesting of products is an essential component of any certification process and any process that does not include periodic retesting is one to avoid.

It is easy to say that establishing any retesting timeline is arbitrary and does not consider the effectiveness of the manufacturer’s quality-control process. Certifiers strive to balance the desire for consumer protection with the business reality that not every batch can be tested prior to sale. Currently, the industry has struck an equilibrium whereby the product is retested on a timeline that is agreed upon upfront, with other certification activities brought into play to supplement that retesting.

Auditing limitations
One might ask why manufacturing creep cannot be handled through auditing processes or by evaluating the product to see if there is a change and only test then. The audit is conducted to ensure that the product stays consistent between the retests, but the retest is still conducted to assess many potential issues that cannot be uncovered through an audit. Performing testing only when a change is proposed discounts all the other factors that affect conformance of the product to the standard and in addition, assumes there is never any manufacturing creep. Variables such as unintentional introduction of external contaminants that may be present in certain environments (e.g. lead) into production processes at either the factory or supplier level, shipping materials, molds and factory conditions can all affect product conformance. No audit can be designed to control all the above factors. In some cases, changes in these factors may be benign, but an audit alone cannot predict the result of changes in any of these variables.

Conclusion
The WQA Product Certification Department test data has shown that products that appear identical on paper (compared to the product as tested in a previous cycle) can fail during retesting. This demonstrates that the retesting process is catching products that should not be on the market but could remain so without periodic retesting. The data is clear. Product conformance cannot be validated without testing and regular retesting of the product. As state governments look more at how to combat water scarcity issues and the contaminant problems that come with it, they are increasingly looking at certified products as a low-cost alternative to massive infrastructure upgrades. If the trust in product certification is eroded, the industry as a whole will suffer. There truly has never been a better time to be in the water treatment industry. We should not erode the trust consumers and regulators have in the certification process by eliminating retesting of products.

About the author
Thomas J. Spoden, CWS, is the Product Certification Director with the Water Quality Association (WQA). He has been with the organization for five years. Previously, Spoden worked at Lake County Public Laboratories and Suburban Laboratories. He holds a Bachelor of Science Degree in chemistry from the University of Illinois in Urbana-Champaign.

About the organization
WQA is a not-for-profit association serving companies that specialize in residential, commercial and industrial water treatment. WQA proudly serves as an educator of water treatment professionals, certifier of water treatment products, public information resource and voice of the water quality improvement industry.

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