Racine Industries, Racine, Wis., is questioning the validity of using x-ray spectrometry (XRF) for testing carpet cleaning extractors, systems and vacuums. These methods are used to establish rankings in the Carpet & Rug Institute (CRI) Seal of Approval (SOA) program. A study conducted by Racine Industries suggests that it is premature to conclude that XRF can be used to quantify soil levels in carpet.

"This method has not been scientifically validated. It has not been reviewed by independent peer reviewers," says Deborah Lema, research and training associate for Racine Industries in a news release. "Also, scientific accuracy, precision and bias have not been determined."

However, CRI president Werner Braun defends the SOA program and says the questions raised in the study have long been addressed and resolved.

"There is nothing [in the document] that has not been addressed either before or since the SOA program was introduced at NASA's John F. Kennedy Space Center in the Fall of 2004," says Braun in a news release. "It is disappointing to see questions listed as unanswered when we have, in fact, answered Racine Industries on multiple occasions in writing."

According to the CRI, an independent validation study has been completed and the scientific paper is undergoing peer review prior to publication. Also, when the SOA program was originally developed, it was done in a collaborative effort with significant input from the carpet cleaning community.

Racine Industries also states that there is no correlation between field and laboratory results for XRF testing. The company is asking for further research to be conducted before SOA is adopted by additional environmental certification standards or government legislation.

However, CRI claims that this testing has already taken place. First, CRI and Professional Testing validated the use of NASA-designer soil in the SOA protocols. Soil-filled vacuum cleaner bags were collected from locations across the United States. After comparison testing, the NASA-designed soil was found to be consistent with the various soil samples collected.

Next, CRI performed numerous "real-world" tests of SOA-certified cleaning products and systems and consistently found that even extremely soiled carpet can be brought back to its original state through the use of SOA products. Finally, correlation studies between XRF and the previously-used gravimetrical measuring methods were also conducted that showed the two methods produced correlated results.