The Cost of Inaccurate CEM Calibration GasesWritten by Leanne Merz
Utility companies and other users of Continuous Emissions Monitoring (CEM) calibration gases often mistakenly consider them a commodity, making price primary purchase consideration. Consequently, many are willing to settle for calibration gases that are less accurate than premium calibration gases, as long as they are also less expensive.
But many companies are beginning to see that buying less expensive and potentially inaccurate CEM calibration gases may, ironically, lead to losing hundreds of thousands or millions of dollars! This is because use of inaccurate calibration gases often leads to overstatement of emissions that could otherwise be claimed as valuable emission credits which are trading at values ranging from $700 to $2,500 per ton.
For instance, if a company uses a calibration gas mixture that has been inaccurately manufactured and certified with a 100 ppm tag value, but in reality contains only 96 ppm, that company would unwittingly calibrate its CEM incorrectly, and overstate its emission levels. Noting image below, this inaccurate calibration gas would eventually lead to tons of lost emission credits that could have been sold, banked for future use, or traded for significant dollars. Now, they are lost forever.
Accurate CEM calibration gases not only allow companies to comply with EPA standards, but ultimately save significant amounts of money in emission credits that might otherwise be lost.
Failing to Measure Up
EPA regulations, as stated in Clean Air Act of 1990, require that protocol gases used to calibrate CEMs for Nitric Oxide or Sulfur Dioxide (SO2) emissions be within ±2% of accuracy value as stated by manufacturer on mixture’s certificate of analysis, or “tag” to comply with EPA-mandated 7 – Day Drift test. However, in a recent EPA blind audit, in which three cylinders of calibration gases were bought from fourteen different specialty gas manufacturers, it was found that 43% of vendors (6 of 14) failed to comply with ±2% accuracy requirement. The inaccuracies, in fact, ranged from 2% to as high as 8%.
Protecting America with Specialty GasesWritten by Bob Davis
Prior to 9/11, environmental concerns largely focused on monitoring, controlling and reducing pollution industrial revolution had set in motion. From a specialty gas point of view, our efforts at Scott focused primarily on developing calibration gases needed to accurately measure emission of hazardous materials into our atmosphere. Over span of 40+ years, we got very good at this, becoming world’s leading supplier of EPA protocol gases used to calibrate Continuous Emission Monitors. Essentially, our role as specialty gas experts involved helping to protect our country from unintentional health and environmental hazards of our industrialized society. Call us naive, but we never imagined we’d be asked to develop calibration gases to protect against deliberate attempts to destroy our society itself. Certainly we were familiar with a growing list of known TICs (toxic industrial chemicals) and need to accurately monitor them. They are unhappy byproducts of industrialization. After 9/11 however, a new acronym crept into our everyday vocabulary: CWAs (chemical warfare agents).