By Thomas P. Palkon

Initial product listings
Companies that currently have products certified (listed) by an American National Standards Institute (ANSI)-accredited product certification body understand the rigor and thoroughness that goes into getting a product listing completed. Although competing certification bodies (CBs) have differing policies (schemes) to complete a product listing, all accredited CBs are required to include the strict requirements of ISO/IEC 17065 Conformity assessment–Requirements for bodies certifying products, processes and services. It is important to understand the goals and objectives of product certification, along with the requirements of a product certification scheme, before we can answer the question of how often products should be tested. The goals and objectives of product certification are:

  • Provide confidence to consumers, regulators, industry and other interested parties that products conform to specified requirements (performance standards)
  • Facilitate trade, market access, fair competition and consumer acceptance of products on a national, regional and international level
  • Allow suppliers to demonstrate to the market that their product has been attested to fulfill specified requirements by an impartial, third-party body

Functional approach
Accredited certification bodies utilize the functional approach when performing conformity assessment activities. The steps to the functional approach are:

Selection. Selecting which product(s) and performance standard should be used
Determination. Determining the requirements of the certification scheme, how they relate to the product(s) and performance standard
Review. Review of all certification requirements and test data
Decision. Has the product met all requirements?
Attestation. Second review of the certification decision, attesting compliance
Surveillance or continued compliance. Factory inspections and re-testing requirements

While using the functional approach to certify products, accredited CBs have a variety of programs/schemes available to them when listing a product. Below are examples of six common scheme types. Most certification bodies that list water treatment products use Scheme Type 5.

  Scheme Type 1a: type test. Attestation of conformity applies only to samples tested.
  Scheme Type 1b: batch test, including 100-percent testing. Attestation of conformity applies to all items in the batch.
•  Scheme Type 2: type test plus periodic testing of products from the market
•  Scheme Type 3: type test plus periodic testing of products from the point of production plus periodic assessment of the production process
  Scheme Type 4: type test plus periodic testing of products from the point of production and/or the market, plus periodic assessment of the production process
•  Scheme Type 5: type test plus periodic assessment of production process and/or audit of management system, plus periodic testing of products from point of production and/or the market
  Scheme Type 6: applicable to certification of services and processes. Initial and periodic assessment of service or process, plus initial assessment and periodic auditing of management system

Understanding who owns the product certification scheme is important. Too often, the performance standard used for product testing gets confused with the scheme owner. Let’s use the US EPA WaterSense program as an example to clarifiy scheme ownership. The agency owns several schemes that have a goal to conserve water. The program does not operate a certification body or testing lab; their scheme uses accredited CBs and laboratories to carry out the requirements of the scheme. When testing and certification is completed, a company is allowed to use the US EPA Watersense mark on their listed products. Scheme owners dictate the product certification mark used on listed products. In this WaterSense example, it is clear that the standard, scheme owner, certification body and laboratory each have their own roles. Confusion occurs when scheme owners also develop standards, operate their own lab and operate their own certification program.

Product certification of residential water treatment products to the NSF/ANSI industry standard(s) is carried out by many organizations. Some of the accredited certification bodies that list drinking-water treatment products include CSA, IAPMO, NSF, UL and WQA. Each organization uses the NSF/ANSI performance standard(s) test results as part of the certification program; however, each organization has created a unique product certification scheme that they follow to list products.

Although performance standards should not include certification scheme requirements, there are times when standards development organizations (SDOs) attempt to influence certification schemes by including scheme requirements. This is typically done in an attempt to control conformity assessment activities such as quality control requirements, re-testing frequency or factory-audit activities. When these requirements are included in a performance standard, they could conflict with the certification scheme requirements. While including scheme requirements in a performance standard is not restricted by ANSI, it could be construed as a restriction of trade, which may violate antitrust polices of standards developers.

Scheme owners and content
There are a variety of product certification scheme owners but the most common are certification bodies, regulatory agencies, trade associations or groups of certification bodies. Product certification schemes are developed around the requirements of ISO 17065. Below is a brief list of some of the critical aspects an accredited product scheme includes.

  • Scope, product requirements, certification requirements and information supplied by client
  • Statement of conformity
  • Mark of conformity
  • Use of certificate and mark
  • Resources for operating scheme-impartiality, competence, outsourcing
  • Reporting results of determination and surveillance activities
  • Dealing with non-conformities: client, product
  • Surveillance procedures
  • Directory of certified products
  • Conditions for certification: granting, withdrawing, etc.
  • Clients’ complaints records, need for verification by certification body
  • Sampling (initial and continued compliance)
  • Acceptance of conformity assessment results
  • Outsourcing of conformity assessment activities
  • Complaints and appeals to scheme owner
  • Licensing and control of mark
  • Surveillance (factory inspection)
  • Non-conforming product
  • Reporting to scheme owner
  • Subcontracting of operation of scheme
  • Fraudulent claim of certification

Continued compliance—how often to re-test products
Maintaining and operating an accredited certification scheme using the functional approach helps ensure we achieve our goals and objectives when listing products. This does not, however, answer our question as to how often to test or re-test products. Now that you have a basic understanding of the functional approach and the six types of schemes, it is probably becoming more clear why most CBs use a Type 5 scheme. It would be impossible for the water treatment industry to conduct third-party testing of every product produced; therefore, certification staff and engineers typically group products into families, based on their similarities. Each family is tested to ensure compliance with the performance standard and is listed if the company and product comply with the certification scheme requirements. One of the critical aspects of a Type 5 listing program is the importance of the quality assurance review conducted at the manufacturing facility. Because the third-party certification body is not able to test every product produced, they must ensure that the company has quality assurance procedures in place that assure the CB that all products produced will comply with the performance standard and certification requirements.

Factors to consider when creating a re-testing plan
There are a number a factors that can trigger re-testing evaluations. First, if the company is seeking to change the product, an engineering review of the change should be conducted to determine which test(s) may be affected. Second, if the performance standard is revised, the listed products must be evaluated to determine if the changes will affect the product’s ability to meet the new requirements. Third, if a company changes its manufacturing facility or process, a review of change and how it may affect the performance of the product should be conducted.

Still, in order to answer the question, “How much testing is enough?” the certification body needs to weigh many factors, such as the thoroughness of the company’s factory quality-assurance procedures, type of internal testing procedures the factory performs, how many complaints the company has received, staff competence, number of products produced each year, if the performance standard been revised and if the scheme has been revised. If the CB does not consider factors such as the ones listed above, they may be re-testing too infrequently or too frequently.

Some organizations attempt to set an arbitrary number of years for their re-testing policy, such as every year, three years, five years or 1/5 of the product every year. Age of test data is an important factor to consider but should not be the only factor to ensure continued compliance of listed products. When implementing a time-based approach the organization is not taking into consideration the many variables that affect product performance, which could lead to non-compliant products on the shelf. A better approach is to conduct a thorough engineering review of the certification file on a regular basis (annually) and compare that review with factory inspection findings and the age of test data on file. This type of holistic review will provide the certification body with the necessary tools to determine when testing should be conducted and which tests should be conducted.

Unfortunately, I was not able to provide a specific time frame that a CB could follow to determine when re-testing products should be conducted. With a complete understanding of an accredited CB’s requirements, however, it becomes obvious that continued compliance is much more than conducting re-tests on a product. CBs have to use a variety of tools to ensure all listed/marked products comply with the performance standard requirements and certification scheme requirements. Conducting certification file reviews annually allows the certification body the ability to inform their listed clients about the required re-testing needed to maintain the listing of each product.

About the author
Thomas P. Palkon, Senior Vice President, IAPMO R&T–Water Systems, is responsible for IAPMO R&T’s product certification program of water treatment products. His technical expertise, laboratory experience and product certification knowledge in the water treatment industry has allowed IAPMO to focus product certification services to the water treatment industry. Prior to IAPMO R&T Palkon worked for the Water Quality Association from 1997-2014. Most recently, he was named Executive Director of the ASSE International Chapter of IAPMO, LLC and will ensure that all of ASSE International’s activities are carried out within the IAPMO Group’s vision, mission and philosophy.


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