A peer-reviewed research paper validating the Carpet and Rug Institute (CRI)’s X-Ray Fluorescence (XRF) carpet cleaning test protocol has been published in the March-April edition of AATCC Review, the official journal of the American Association of Textile Chemists and Colorists.
Titled, “X-Ray Fluorescence Spectroscopy Method Development for Quantitative Evaluation of Carpet Cleaning Technology”, the paper is authored by G.H. Asbury of Professional Testing Laboratories and R.F. Shannon of KeyMaster Technologies, Inc.  The seven page report examines the processes used to test and verify the removal of soil from carpet using X-ray fluoroscopy equipment. The paper concludes that XRF measurement is a reliable means of quantifying the amount of test material removed from carpet during cleaning.
CRI has committed to incorporate XRF technology in its testing programs for high efficiency vacuums, carpet extractors and effective carpet cleaning products. “This technology is consistent with CRI’s desire to see the best science applied to cleaning carpet and improving air quality in indoor environments and maintaining the life cycle of carpets,” said Werner Braun, president of the CRI.  “We have made XRF technology a central part of our Seal of Approval programs.”
Michael Berry, Ph.D., former Deputy Director of the EPA’s National Center for Environmental Assessment and a leading authority on Cleaning for Health and indoor air quality stated, “In my 30 years’ experience, the XRF technology is the first scientific approach to quantifying carpet cleanliness that I will stand behind 100 percent.”
What is X-Ray Fluorescence?
The original technology (TRACeR III-V) was developed by NASA in 2002 to conduct quality control for critical aluminum alloy parts destined for the space shuttle. Evaluation of these parts is critical for the Space Agency, as any signs of contamination, corrosion, or material deviation could compromise a space mission. Shaped like a portable drill and weighing less than 5 pounds, the TRACeR III-V has proven successful in chemical substance identification and analysis.
The technology set the stage for a major breakthrough in carpet cleaning validation, helping to create stricter standards for today’s vacuum cleaners, carpet extractors and other carpet cleaning products to ensure that they are removing soil.
NASA and KeyMaster Technologies (Kennewick, Washington), in collaboration with CRI and Professional Testing Labs (PTL) (Dalton, Georgia) developed techniques to use the NASA-enhanced analyzer to test the effectiveness of various carpet cleaning methods.   
How Does It Work?
The XRF instrument emits energy and excites the atoms of the target elements found in the simulated carpet soils.  The energy generated in response is called X-Ray Fluorescence , which can be detected and measured by the device.  Each atomic element has its own unique energy signature.  The XRF instrument measures each energy signature to determine the presence and concentration of various soil elements.
A standardized or synthesized soil that mimics actual soil and foreign particulate contaminants is applied under controlled conditions to carpet.  The lab soil contains five elements chosen for the particle size and physical characteristics of carpet soil. That this simulated soil effectively replicates real world soils was demonstrated by correlated field studies in a number of locations.
On a test bed in the lab, the X-Ray Fluorescence instrument measures the amount of soil applied to and removed from the carpet sample.  By repeating this process with different vacuum cleaners and extraction machines that use water, chemicals, or a mixture to clean carpets, the lab can establish performance benchmarks.
“XRF is a great technological leap forward for measuring carpet cleaning effectiveness, and we believe this test will be adopted universally as a key standard for validating cleaning performance,” says Gary Asbury, president of PTL.
Benefits to Professional Cleaning
Carpet-cleaning professionals that select equipment and other products based on CRI’s XRF testing as a general rule can simply clean carpet better than those who don’t.
These products must meet the Institute’s tough standards for soil removal (as validated by XRF testing), water removal, and surface appearance to receive the CRI Seal of Approval.
Since soil removal is the primary test, efficiency is rated on four levels: vacuums, extractors or systems that exceed average soil removal receive a Bronze Seal rating; those achieving higher soil removal receive a Silver Seal rating; products removing yet more soil receive a Gold Seal rating, and those removing the most soil receive a Platinum Seal rating.
Using SOA products validated by XRF testing not only helps ensure carpet is cleaned better, but that the indoor air is cleaner too.  “Removing dirt and particles from a carpet and containing them within the best performing vacuum helps improve overall air quality,” says Asbury.
“The Seal of Approval program now qualifies vacuums that release less than 35 micrograms of total particulate per cubic meter of air - that's less than 1/1000th the size of a grain of salt. That's vanishingly small,” added Braun.
For more information, contact Pat Jennings at 706.428.2123 or pjennings@carpet-rug.org. To find a complete list of SOA-approved products, click here.