• No method validation study has been completed or shared. Among other things, method validation studies are necessary to ensure that a test method works.
• Outside XRF experts have doubts that this way of using XRF is effective.
• This type of XRF technology works best with a flat, even surface. Carpet is not a flat, even surface.
• Where the soils are on the carpet fibers matters to XRF. The same amount of soil at the top of the fibers is reported as a higher amount than if it was at the base of the fibers. Therefore, if leftover soil is moved at all during a cleaning, or if the carpet yarns aren’t returned to the positions they were in before cleaning, the XRF readings will have errors.
• The carpet in this testing scenario is moving on a conveyor. There are questions about what this does to test accuracy.
• The composition of the designer soil used in the PTL test is similar in some respects to vacuumed dirt. However, extractors are designed to clean the dirt left behind after vacuuming, so using designer soil based on vacuumed dirt to test extractors, etc. is not appropriate.
• Dirt used in the test samples is not walked into the carpet fibers as soil would be in a real-life situation.
• What is the accuracy or uncertainty in the SOA’s XRF measurements? What evidence is available for those using SOA products or for a purchaser of SOA testing that the SOA XRF testing produces useful measurements? The analytical quality is unknown.
“There are numerous questions regarding the testing methods used in the SOA program,” added Lema. “With this summary, interested parties and stakeholders will have a quick reference of what questions to ask when reviewing the testing protocols.”
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About Racine Industries Inc.
Founded in 1935 as the Rench Manufacturing Company, Racine Industries Inc. is known for its innovative dry extraction carpet cleaning system which is used in commercial, institutional and residential carpet cleaning in 60 countries worldwide. They are the pioneers of the concept of extracting during carpet cleaning…either wet or dry extraction. Racine Industries is headquartered in Racine, Wisc. For more information, go to http://www.hostdry.com/