By Tina Fischer, CWS-VI

Certification is a complicated process on the surface. But once it is broken down into digestible pieces, the procedure itself and reasoning behind how products obtain certification is quite simple.

Certification types vary most commonly by the standard to which they are certified. There are many drinking water treatment unit (DWTU) standards and each standard focuses on a specific treatment technology. For example, the NSF/ANSI 42 standard (which will be the focus of the discussion) provides details regarding protocols and requirements for the certification of water filters.

One of the most easily confused aspects of certification is the reasoning behind certification of a system that is comprised of components that are already certified. It is commonly assumed that by combining a multitude of already certified components or pieces that implies or provides certification for the complete system without any further evaluation. While the basis of this assumption carries some validity with it, the reality is that multiple component certifications do not equal a complete system certification.

Component certification
It is important to understand exactly what a component certification is about. While the standards allow for components to maintain individual certifications, these certifications are listed with materials safety and/or structural integrity requirements only. Components alone cannot hold certification for performance claims.

To provide two examples, when a cartridge manufacturer chooses to certify an activated carbon filter cartridge, the product would be tested and certified for materials safety only. The actual function and performance capabilities of the cartridge are not tested for or certified.

Consequently, when a housing is certified as a stand-alone component, it is certified for materials safety in addition to structural integrity. This is because it would be considered a pressure-bearing component.

From the examples above, two main components of a water filtration system have gone through the testing and certification process. Assuming that all other components of the filter also have certification, why is it that the filter as a whole is not certified? And consequently, for what reason would a manufacturer spend the time and money to obtain certification on their components if the component certification is not easily transferrable to its customer, the end use product manufacturer?

Drinking water treatment
In order to answer the questions, it is best to break down the certification requirements into the four main sections of the drinking water treatment unit standards. These sections include materials safety, structural integrity, performance and literature, along with the facility inspection itself.

Accredited certification agencies are required to perform facility inspections to ensure that the products being manufactured are consistent with the specifications provided when the certification was issued. For sake of clarity, the four sections of the standard and the facility inspection will be analyzed individually.

The materials safety section:
While it is possible to obtain certification using all individual component certifications, there are steps that need to be evaluated first. Because all of the components were tested separately, the analytical results from each of these extraction tests must be combined to ensure that the accumulation of the individual parts will not elicit any contaminants extracting at concentrations above the allowable limits of the standard.

For example, if a manufacturer is piecing together four different certified components to make a system and each of the four components individually extracts five ppb of lead, individually, they all meet the 15ppb requirement set in the standard. However, when combined, the lead concentration would be 20 ppb which exceeds the allowable limit set in the standard.

Furthermore, it is important to ensure that the surface-area-to-volume ratios of the tested component are worse case when compared to the surface-area-to-volume ratio of the component in the complete system. In this case, if no contaminants are above allowable levels and the surface-area-to-volume ratios of the tested unit is worse case, then the original test data may be used to verify that the materials safety of the complete system is in compliance with the standard. The equipment manufacturer would not be required to perform any additional extraction tests, which easily equates to thousands of dollars in savings.

The structural integrity section:
It is also possible to obtain certification using a combination of the originally certified components’ structural integrity test data. To simply rely on a component certification and transferring that data is impossible.

Based on the standard requirements, it is important to ensure that the cycles and pressures at which the components were tested at are equivalent to or more stringent than the pressure at which the complete system must undergo. Most commonly, when a component is tested for structural integrity, the data is worse case and will be transferable for a complete system certification.

The performance section:
Unfortunately, when it comes to components, the performance section of the standard is not a section in which a manufacturer can obtain certification. While it is very common for a cartridge manufacturer to also conduct performance reduction testing, the contaminant reduction testing is not certifiable.

There are many reasons why these claims cannot be listed as certified. The two most prominent reasons are the changes to flow rate and bypass that may occur when a cartridge is placed into a complete system.

The flow rate of a system dramatically affects how a filter cartridge reduces the contaminants with which it comes in contact. Therefore, any changes to the flow rate that would reduce the performance capabilities would nullify the certification.

Additionally, when a cartridge is placed into a system, there is great concern regarding the seals of the system and whether or not the contaminants being introduced can completely bypass the filter. The time and money component manufacturers spend on checking performance claims for components are not completely lost.

Certification agencies are able to perform spot check tests to satisfy the need for seal and flow verification. If these tests determine that all specifications are within the allowable ranges, the test data may be used for certification without a full range of testing for each contaminant.

The literature section:
All certifications require some sort of literature compliance. These requirements vary widely when component literature is compared to DWTU literature. Because components are certified for materials safety and/or structural integrity requirements only, the literature requirements are minimal. Depending on the specific type of product, as little as a product label is needed for a component certification. However, complete systems are required to have many different pieces of literature including an installation/operation manual, a performance data sheet, a data label and in the case of water filters, replacement component literature.

The system literature is much more diverse and includes specifications about the performance of the end product. Regardless, there are literature requirements for both types of certification.

The literature must be reviewed and approved by the certification agency to deem compliance with standard requirements. Without this review, the literature for a complete system would not be evaluated to determine if it meets the requirements found in this section of the standard.

The facility inspection:
Facility inspections may be the most important aspect of a certification. Certainly, meeting the standard and abiding by certification policies are important.

However, it is impractical to believe that any one manufacturer could test every manufactured product with a third-party listing agency. Therefore, a facility inspection is required to ensure that each product is manufactured in the same manner. It is true that if a component is certified, the component manufacturer will be audited.

Just confirming that each individual component has been manufactured consistently will not ensure that the final end product, a combination of the individually certified components, is being manufactured consistently. Without going through an accredited certification agency for certification of the complete system, production processes would not be reviewed, and therefore, a claim of system certification would not be valid.

Product certification confusion
While on the surface there seems to be a good argument for assuming product certification can be granted if all of the components are certified. However, there are many other steps that need to be evaluated before certification can be granted for the assembled product.

Combining certified components provides a system manufacturer some assurance that it will meet the requirements of the standard. However, combining certified components does not authorize the advertisement of a certified system.

This discussion focused on one type of technology—filtration. However, there are various types of drinking water treatment technologies. While specific examples were noted for water filters, the basic concepts and ideas of using component certifications for complete product certifications are the same for all other treatment technologies.

Component manufacturers obtain product certification to provide assurance that the components they are selling meet the requirements of the standard. However, component manufacturers cannot guarantee that combining their component with another component will do the same. It is up to the certification agency to verify that.

Thus, the need for system certifications is apparent. In the end, obtaining component certification can prove to be extremely beneficial.

The test data for these component certifications may be used to qualify a complete system for certification. Unfortunately, a manufacturer cannot transfer multiple component certifications to make a complete system certification without getting a certification agency involved for verification purposes.

About the author
Tina Fischer is the Product Certification Supervisor for the Water Quality Association’s Gold Seal Program, having worked for over 7 years at WQA to develop Gold Seal as an organized ANSI and SCC accredited program. Tina and Melissa Tonsor can be contacted at WQA to provide additional information on obtaining all component or system certification. Tina can be reached by telephone (630) 505-0160 ext. 533, facsimile (630) 505-0752 or email tfischer@mail.wqa.org

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