Continuous Emissions Monitor Certifications


Holcim (US), Inc.


Clarksville, Missouri

CEC Services

  • Air Quality Services

Owner Objective

Holcim (US) Inc. is one of the largest suppliers of portland and blended cements and related mineral components in the United States. Holcim has quarterly audits conducted of their Continuous Emissions Monitoring System (CEMS) at the Holcim cement kiln in Clarksville, Missouri.

CEC Approach

CEC has been retained to conduct these quarterly audits. For these projects, CEC personnel were responsible for conducting the Relative Accuracy Test Audits (RATAs) and continuous emissions (CE) surveys, and preparing the final RATA and CE reports. The testing was conducted to demonstrate compliance with the CEMS monitor certification requirements of the Boilers and Industrial Furnaces (BIF) regulations governing CO and O2 CEMS.

Using primary and back-up systems, the CEMS installed at the cement facility are extractive monitoring systems, which continuously monitor the CO and O2 concentrations at the mid-kiln location. The mid-kiln CEMS have a range of 0-25% O2, with a CO range of 0-200 parts per million (ppm) on the low side, and 0-3000 ppm CO on the high. Each CEMS is installed in a self-contained, environmentally-controlled shelter.

They conducted a series of nine test runs for each RATA on each CEMS, and provided preliminary relative accuracy test results immediately following each test. This assured that the relative accuracy requirements of the CEMS were being met. Prior to calculating the relative accuracy, the carbon monoxide concentrations were corrected to 7% O2.