Continuous monitoring systems (CMS) are devices required by most regulatory programs to monitor, record and document a facility’s operation. A CMS is a general term that includes continuous emission monitoring systems (CEMS), continuous opacity monitoring systems (COMS), continuous parametric monitoring systems (CPMS), continuous emission rate monitoring systems (CERMS) or other manual or automatic monitoring systems. Some of the fundamental compliance requirements for CMS devices include design and installation, calibration and recordkeeping.
The design and installation of CMS devices are an important factor in obtaining representative samples and creating easy access for calibration and maintenance purposes. Sampling locations should be determined based on regulatory requirements, and where a representative sample of the process parameter or the emissions from the source is being monitored. Additional factors for locating CMS sample interfaces include sample conditioning requirements, ability to collect a representative sample of the total emissions, in-leakage concerns and severe flow disturbances such as cyclonic flow. Other design criteria to be considered include monitoring system span values and recording scales. The span values are determined by the operation of the unit and its regulatory requirements. While the recording scale is not typically an issue with electronic devices, the readings should be within the range of the instrument and have a resolution within 0.5 percent of the span value.
The calibration of a CMS device is a regulatory and manufacturer’s requirement to ensure accuracy of the device being used. The accuracy of a device is the comparison of a true or known value to a measured or actual value. Different CMS devices require different calibrations and calibration periods to ensure their accuracy. Some of the calibration periods or types may include daily calibrations, quarterly accuracy testing, interference response tests, relative accuracy test audits, calibration error, drift tests and calibration checks. The Code of Federal Regulations has set forth the type and requirements for calibration and accuracy check of the CMS device based on the unit being evaluated. However, the manufacturer may require a more stringent calibration and accuracy check of the CMS device.
The recordkeeping requirements for each operator are defined by the regulatory agency based upon the type of permit or permit level. One of the recordkeeping requirements includes operating data with all required measurements, malfunctions, inoperative periods, maintenance performed and out-of-control events. Another aspect of the recordkeeping requirement is the retention and location of the records. In general, the regulation or permit will define the retention period and expected location of the records. This record-keeping aspect is important because it allows an auditor to review the process history of the unit in determining potential deficiencies. As a part of the recordkeeping process, a quality assurance/quality control (QA/QC) program is typically required for CMS devices. The QA/QC program must be a written program that defines, at a minimum, the design and installation, calibration and recordkeeping requirements for the CMS device. The writ-ten QA/QC program must be available for review by an auditor or the agency. The QA/QC program must be revised if a CMS device is modified or replaced, or if there are excessive inaccuracies caused by the procedures in the program.
In short, a CMS device is a part of a facility’s operation or process that is regulated by agency rules and regulations. The CMS requirements include, at a minimum, design and installation, calibration and recordkeeping requirements. In addition, the operator must comply with any permit requirements and, if more than one set of regulations applies, the most conservative requirements if not otherwise defined within the permit.
For more information, contact Elizabeth Drake at (281) 286-1861 or edrake@cs2inc.com.