DO NOT trust a Dog or an X-Ray Gun to detect Chinese Drywall

I originally wrote this article back in 2009, but I’ve recently learned of more CrAzY inspectors offering these types of inspections.

DOG
If you call around enough places you’ll find an inspector who has supposedly trained his dog to sniff out Chinese Drywall. While K-9’s have a very sensitive sense of smell, it’s doubtful that the training the inspector’s dog (or the inspector) has received is very thorough. Both the K-9’s and their handlers used in law enforcement, search & recovery, medical alert, etc. undergo years of extensive training, certifications, and continuing education by both Federal and State Canine Associations; and very few make the cut. After a state-wide search, we were unable to find ANY dogs certified (by a reputable organization) to successfully detect Chinese drywall without a ridiculously high rate of misses &/or false hits.

X-RAY GUN
When an inspector claims to have a “Special Gun” “X-Ray Gun” or “Chinese Drywall Gun,” he/she is likely referring to the Thermo Fisher Scientific XRF Analyzer. In fact, the manufacturer states: It was made to determine the break-down of soil. It can SOMETIMES detect SOME TYPES of gypsum that are SOMETIMES found in SOME TYPES of Chinese drywall, but it is no way accurate, thorough, or conclusive. It was not made to detect Chinese drywall, and should not be used as such. Further, Ron O’Brien, Director of Public Relations at Thermo Fisher Scientific stated (paraphrased): The XRF Analyzer is not recommended for use as a “Chinese Drywall Detector.” If someone uses the XRF gun for the purpose of attempting to determine the presence of specific materials, it should be intended as a preliminary screening method that may detect materials that could prompt you to back up your findings by a confirmatory test which would include a “destructive” inspection – including removing sheets of drywall to examine them for manufacturer’s labels/markings, &/or taking samples for more thorough laboratory testing.

UPDATE 08/2010: More Evidence Against X-Ray Guns

XRF = X-ray fluorescence ~ the emission of characteristic “secondary” (or fluorescent) X-rays from a material that has been excited by bombarding with high-energy X-rays or gamma rays.
This process has been used to detect Strontium Sulfide (SrS) levels exceeding 2,000 mg/kg (ppm), which was initially thought to indicate that the gypsum used in the drywall was mined in China.
FIRST – Many inspectors are not properly trained to properly use an XRF Analyzer or properly interpret the readings from that tool.
ADDITIONALLY – Extensive testing has determined that XRF Analyzers can produce false-positive results (see below).

Florida Department of Health
IDENTIFICATION OF HOMES WITH CORROSION FROM PROBLEM DRYWALL, AUGUST 27, 2010.
Testing was conducted on a wide range of drywall samples and found that the use of strontium as a marker resulted in false-positives where some non-problem drywall samples (based on chamber testing) were found to contain elevated strontium levels. The Federal Inter-agency Task Force [staff of the U.S. Consumer Product Safety Commission (CPSC) and the U.S. Department of Housing and Urban Development (HUD)] does not believe strontium has a causative role, and in light of the possibility for false-positives we no longer consider elevated strontium levels to be valid corroborating evidence for problem drywall.

The Task Force now believes that the best and preferred practice for identifying the presence of Chinese drywall in a home does not include the use of strontium as one of the corroborative factors previously set forth by the Task Force. The Task Force is now removing from the “Step 2” list of corroborating evidence in the Interim Guidance the factor addressing strontium levels in excess of 1200 ppb. The Task Force does not believe strontium has a causative role in the problems reported with the problematic drywall. Furthermore, the Task Force believes it is appropriate to remove the strontium level as a corroborative factor due to the possibility that its use may lead to false-positive results where a homeowner may mistakenly believe their home contains problem drywall.

SOURCE:
SUMMARY OF REVISION 1 TO THE INTERIM GUIDANCE – IDENTIFICATION OF HOMES WITH CORROSION FROM PROBLEM DRYWALL, AUGUST 27, 2010.

There’s just no short-cut. A proper inspection requires a thorough inspection for both the physical evidence of contaminated drywall AND evidence of any off-gassing. That’s what we do at Sherlock Home Inspections.