Certifying and Recertifying Your Continuous Emissions Monitoring System (CEMS)

Continuous emissions monitoring systems (CEMS) are typically required to be certified or recertified in accordance with performance specifications such as Appendix B to 40 CFR Part 75 and the Performance Specifications (PS) of Appendix B to 40 CFR Part 60. Certifying a CEMS may sound straightforward, but it requires careful planning of testing timelines and avoiding unscheduled maintenance. Some state or local agencies have their own requirements or guidance as well, which can either muddy the waters or clear them up.

This article will cover both initial certification and recertification, with the latter being the emphasis, because there is more gray area surrounding recertification procedures. When we say “Initial Certification”, that refers to an entirely new CEMS that has been installed on an emissions unit. Conversely, “Recertification” refers to a replacement of your CEMS or one of its major components.

There are several things to consider in the certification process that will be discussed in the following sections:

• Transparency and Notification
• Monitoring and Quality Assurance/Quality Control (QA/QC) Plans
• Testing
• Data Validation
• Reporting

Transparency and Notification

When certifying your CEMS, one of the best things you can do to avoid any agency scrutiny is to send them a notification regarding the certification. Being proactive is better than being reactive. While some permits and rules will require notification, it’s best practice to submit a notification regardless. This notification should include the changes made, timelines, and/or impacts on data. Transparency with the agency ensures alignment with agency expectations and prevents unexpected downtime that could lead to penalties/enforcement action.

Monitoring and QA/QC Plans

For the benefit of the facility, we recommend updating the monitoring plan associated with the CEMS after any certification process. This plan describes the monitoring system, locations, and the collection of data, effectively documenting the monitoring for compliance purposes. Part 75 requires this update to occur but Part 60 and 63 do not explicitly state this requirement. The same goes for the QA/QC plan. This plan helps to clarify these gray areas, which is especially important during times of change. The opportunity to revisit the QA/QC plan content should be used to check that the certification requirements are addressed and that any gray areas are addressed. It is recommended that the plans be updated regardless of the applicable regulation.

Testing

The testing required to certify a CEMS depends on the regulations that apply to the CEMS. These tests verify both the accuracy of the analyzers and the performance of the entire measurement chain—from the probe and sampling lines to the conditioner, analyzers, and data acquisition and handling system (DAHS). For example, Part 60 typically requires a seven-day drift test and relative accuracy test audit (RATA) for most gaseous pollutants. If these tests are not completed successfully, the CEMS are not certified and monitor downtime will accrue. Careful planning is essential before replacing CEMS components to have a successful certification test period.

Data Validation

Once testing is complete and passed, data can now be considered valid. Avoiding CEMS downtime is one of the goals that you will have to consider during the certification process. The data validation is crucial to determining how compliance averages will be built. In some cases, you can consider your data “conditionally” valid from the time a CGA is passed during the installation. Each regulation is different with respect to when the valid data period will start, whether it is well defined or absent. For example, Part 75 provides guidance that valid data begins with the “probationary calibration error test”, which is essentially the first calibration that occurs after the installation or replacement of the CEMS. Part 60/63, however, does not have any specific guidance on when the certified data begins, so it is suggested to gain approval from the agency on how the facility plans to handle the beginning of certified data.

Reporting

After CEMS certification testing is complete, submit a report to the regulatory agency confirming that certification is finished and that all plans have been updated as needed. This allows the agency to address any issues promptly. Additionally, if reporting expectations are unclear, contact the agency for guidance. At a minimum, we recommend including language in your quarterly or semi-annual CEMS report to let them know that the recertification occurred and the certified start date and time for the new or upgraded CEMS.

Conclusion

Each of these topics must be considered when you are planning to certify your CEMS, whether it is following the initial installation of the equipment or the replacement of a major component of the CEMS. Where there is gray area for your CEMS, we recommend using guidance available from other regulations or state and local agencies. It is always recommended to confirm and document the approach with the agency before moving forward with your plan.

For additional details on this topic, please check out our webinar and request the recording. The ALL4 CMS Tech Team is available to assist and provide recommendations throughout the certification process.

If you have any questions about this topic, please contact me at bjohnson@all4inc.com or (502) 874-4500.

References:

• https://www.all4inc.com/insights-webinars/filling-in-the-gaps-for-replacement-and-recertification-of-continuous-monitoring-systems-CMS/
• https://www.ecfr.gov/current/title-40/chapter-I/subchapter-C/part-75/appendix-Appendix%20B%20to%20Part%2075
• https://www.epa.gov/emc/emc-performance-specifications