By Rick Andrew
Most of us are familiar with the general idea of testing and certification of POU/POE products. We know there are standards and protocols for evaluation of this type of equipment, and we might even have some insights on what type of testing is required under these standards and protocols and which apply to which products. However, the full scope of available standards and their requirements can be overwhelming, even to those who are in the manufacturing sector and are engaged with new product development and regulatory compliance. For example, how many people know that there are actually eight different NSF/ANSI standards and three different NSF protocols for evaluating POU/POE products? Probably not many.
Each of these standards and protocols includes similar general requirements. These requirements address various aspects of the products regarding safety, appropriateness for purpose, essential user information, etc. A summary of these requirements is presented in Figure 1.
Although these general requirements are very important (especially material safety and structural integrity) and there are some differences in how the general requirements are tested and evaluated in the various standards and protocols, these general requirements are not the reason there are so many different standards and protocols. The general requirements are similarly addressed across all of the standards and protocols and in some cases they are identical across several of them. If it were only for the general requirements, we would not need to have so many standards and protocols.
Scope and contaminant reduction claims
The scopes of these standards and protocols can generally be described across three categories:
- Technology: RO, UV, cation exchange, etc.
- Product application: POU or POE, complete system or component
- Contaminant reduction claims: Scope of available claims, any mandatory claims, etc.
Basically, different technologies have different capabilities, limitations and configurations, so it is logical to create standards and protocols according to technologies. That way, the scope of the standard, the contaminant reduction claims available and testing methods are appropriate and applicable to the technology addressed in that particular standard or protocol.
For example, POU RO systems are constructed differently, operate differently and provide different treatment from POE cation exchange water softeners. Criteria that are important for evaluating POU RO systems, such as TDS reduction performance and daily production rate determination, are not applicable to water softeners. Similarly, fundamental criteria for evaluation of POE cation exchange water softeners, such as pressure drop and softening capacity, have no relevance to POU RO systems. It only makes sense to have separate standards for evaluation of these two different types of technologies and systems.
When considering the various types of POU and POE technologies existing in the market, and the different end uses and functions they can have, it becomes more understandable that there are eight different NSF/ANSI standards and three different NSF protocols for evaluating POU/POE products.
Figure 2 provides a summary of the scope and contaminant reduction claims available in the NSF/ANSI standards and NSF protocols for POU/POE products.
A summary overview
The NSF/ANSI standards and NSF protocols for POU/POE products are very rigorous, scientifically based documents, with very detailed information provided for testing methods to facilitate reproducibility of test results among various laboratories. Exploring these details and the history, science and rationale behind them can be a fantastic learning experience. However, it is quite easy, and maybe even inevitable, in this pursuit to lose sight of the forest for the trees.
Instead, we present here a very general summary overview of the various standards and protocols to help provide a big-picture look at their structure and how they interrelate with each other, as well as a high-level overview of the requirements. This overview can be helpful as we match up products with standards and/or protocols and to help us keep clear on which standards apply to which types of technologies, products and contaminant reduction claims.
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