- THE MAGAZINE
“When NASA press releases make the claim that this XRF testing measures the water in carpets, which is invalid, or when the vice president of marketing from a major carpet mill says that this XRF testing sees cleaning product residue as well as the designer soil, which it doesn’t, it is obvious that even the people most involved with the CRI SOA program are confused or misinformed,” said Deborah Lema, Research & Education Associate, Racine Industries. “We put together some of the main points and questions that we still have in a concise list, so that those impacted by the SOA program may more briefly and easily refer to them. Our hope is that this will increase the demand for additional evidence, testing and transparency.”
Some of the key points of the Summary Reference Guide:
- 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.
For a full copy of the reference guide, go to www.carpetdiemblog.com.