The most common methods for drywall testing are not new technologies, but new uses of existing and credible technologies. Both XRF and FTIR have been used for quite some time.
XRF utilizes x-rays to analyze a material for a specific element. As it relates to Chinese drywall testing, XRF is used to identify strontium. Without getting too deep into the science of XRF, the basis involves the change of energy of electrons within the atom of the targeted element. Every element has a different arrangement of electrons. The electrons are situated in orbitals of varying energy levels. When the element is bombarded with X-rays, an electron is expelled from the atom, vacating its orbital. An electron from a higher orbital steps down to fill the spot vacated. When that happens, trace amounts of energy are given off. Measuring the specifics of that energy is used to identify the atom. In the case of drywall testing, the measurement is used to identify the level of strontium in the sample.
FTIR is a very different test. As it relates to drywall testing, FTIR is used to measure calcium carbonate concentrations. As opposed to X-rays, FTIR utilizes infrared light. This light is sent through the sample. Certain segments of the light spectrum will be reflected and other segments will pass through. Measuring these spectrum and comparing them to a library of known values identifies the elements of an unknown substance. When performing a Chinese drywall test, the element in question is calcium carbonate.
Although both technologies are well established and accepted to be very accurate, they cannot accurately be used alone to perform a Chinese drywall test.
In our experience, each test alone produces about 98% reliable results when dealing with strictly domestic vs. defective drywall. The concern is that the 2% will produce a false negative, the ramifications of which are significant. A reliable drywall test must also take into account blend drywall product. The CPSC has identified three categories of drywall:
1)Samples with low levels of both calcium carbonate and strontium
2)Samples with high levels of both calcium carbonate and strontium
3)Samples with high levels of calcium carbonate and low levels of strontium
In a drywall test, category one is considered domestic and non-problematic drywall. Category two is considered to be Chinese drywall or defective drywall. Category three is considered to be blend (domestic and problematic) drywall. A drywall test that did not utilize both XRF and FTIR would not accurately identify the blend material.
Another important consideration for a Chinese drywall test is the sampling method. The CPSC has issued guidance that drywall core samples should be used. With this method, contamination from paint, drywall compound (mud), wall paper, etc is not a concern. Some inspectors are offering drywall tests during which they simply shoot the face of the drywall with an XRF gun. Not only do these tests lack the combination of XRF and FTIR necessary, they also do not apply the single technology correctly. The sales side of this drywall test is that an XRF gun can be brought to the home and used to non-invasively sample the drywall. The truth of the matter is that the decisions that are based off of these drywall tests are too significant for anything short of the most accurate and thorough tests possible.
We are able to collect core samples and analyze the samples in a way that is discrete and not noticeable during normal conditions. This way, we are able to analyze core samples against both XRF and FTIR and provide an affordable drywall test.
Joseph Weissglass is a leader in drywall testing and drywall inspections. As the Founder/President of Certified Chinese Drywall Testing, Weissglass developed the nation’s only insurable drywall testing protocol. Read more about drywall testing at http://www.certified-chinese-drywall-testing.com.
Distributed by http://www.ContentCrooner.com
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