Racine Industries released a white paper that examines the methods of using x-ray spectrometry (XRF) for testing carpet cleaning extractors, systems and vacuums. The methods are used to establish rankings in the Carpet & Rug Institute Seal of Approval program.

Findings from the study “suggest that it is premature to conclude that the testing accomplishes the stated objective of quantifying soil levels in carpet and encourages further research before there is widespread acceptance of the SOA program.”