Testing requirements for carpet cleaning machines are beginning to look more like rocket science. With the aid of special x-ray fluorescence technology developed with the help of NASA scientists, the Carpet and Rug Institute (CRI) has brought a new level of cleaning to its recently launched Seal of Approval program.

The NASA-enhanced technology, called XRF, measures precise amounts of soil removed by a carpet extractor. To gain the Seal of Approval, extractors cannot leavel more than tracea mounts of residual water. The standard also takes into consideration the amount of wear and tear. A CRI technical committee sets the standards for the program and an independent laboratory administers the tests.

Five manufacturers have been awarded the Gold Seal of Approval for their truck mount extractors, signifying the highest level of soil removal. They are Mohawk FloorCare Essentials, Sears Carpet & Upholstery Care, Prochem, ZeroRez and CleanMaster.

Bronze Seals of Approval, signifying a lesser but still significant level of soil removal, were won by US Products for its portable extractors, and Rug Doctor for its self-contained extractor.

No companies have yet earned the Silver Seal of Approval.

The new CRI Seal of Approval program also tests and certifies spot removal and pre-spray/in-tank cleaning products. Vacuums and cleaning systems will be added to the program at a future date, CRI says. For a listing of all certified products, visit CRI's website at www.carpet-rug.org.