Vista Engineering Develops Statistical Certainty Methods for Toxic Drywall Identification
As of April 2, 2010, homeowners are urged by multiple federal agencies to remove all toxic wallboard (imported drywall, Chinese drywall, etc.) along with contaminated electrical components, electrical wiring, gas service piping, fire suppression systems (sprinkler), smoke alarms, and carbon monoxide alarms. These agencies have developed specific guidelines to determine if your wallboard is considered to be toxic; however, these guidelines require the use of high-tech, expensive equipment capable of accurate quantitative measurement of specific elements.
Vista Engineering has invested in the experience and high-tech equipment to determine the generally accepted levels of various elements in wallboard based on these federal guidelines. Vista Engineering will develop a signature spectrum and element table for the suspect wallboard by analyzing the wallboard’s chemistry using (EDS) x-ray spectroscopy. Chemical analysis can be difficult when analyzing wallboard specimens which are composed of multiple materials types consisting of both light and heavy elements. Vista has developed a procedure to optimize the analysis of wallboard specimens based on ASTM standard E1508. The procedure developed by Vista is used to determine if wallboard specimens exceed the current recommended criteria for toxic wallboard.
Vista Engineering welcomes wallboard specimens for analysis from both independent home inspectors and large-scale inspection agencies. All chemical analysis measurements are collected and analyzed in-house by our scientific and engineering staff to insure optimum collection results. Collected data is compiled and presented in tabular format listing the elemental composition in parts per million. If desired, a statistical range of toxic certainty and toxic probability for each specimen can be determined. Statistical analysis is performed based on a t-distribution. An attached graph shows the probability for error versus the number of measurements based on the t-distribution. Vista requires a minimum of five measurements per sample when performing a statistical analysis. Like any statistical analysis, toxic wallboard certainty will improve with an increasing number of measurements.
Another indicator of toxic wallboard developed by federal agencies involves monitoring the corrosive activity of copper in a controlled environment with wallboard material. Vista Engineering is capable of performing climate controlled analysis via an in-house environmental chamber. Vista’s environmental chamber is capable of reproducing specific environments by maintaining temperature and humidity conditions for extended periods of time. To perform this test, copper wire is placed directly adjacent to the wallboard in question and held for a specific time period in a controlled environment. The copper wire surface is periodically evaluated for any signs of darkening or discoloration which would be a direct indicator of toxic wallboard.
Vista Engineering’s client base includes the U.S. Army, Department of Energy, National Institute of Health, General Electric, major automobile manufacturers, large and small scale utility companies, and many others.
Below are examples of damage caused by toxic wallboard.
