Importance of Calibrating Continuous Emission Monitoring Systems (CEMS)
CEMS are among the most important control tools in modern industry. These systems provide continuous measurements of pollutant emissions from stacks, including NOx, SO₂, CO, particulates, VOCs, moisture, oxygen, and more.
The data produced serve two main purposes:
- Compliance with environmental regulations in business licenses and emission permits
- Operational monitoring to improve processes and reduce costs
To ensure that the data produced by the system are reliable, accurate, and valid for regulatory reporting, calibration must be performed according to EN‑14181 and the Ministry of Environmental Protection’s CEMS Calibration Protocol.
Environmental and Regulatory Challenges
- Invalid monitoring data
- Exceedance of emission permit conditions
- Regulatory enforcement and fines
- Difficulty identifying trends or system malfunctions
- Inability to present reliable data to authorities
Calibration and Testing Process at Ecological Laboratories A.P. Ltd.
QAL2 – Five‑Year Calibration
- Preliminary inspection of the stack and monitoring system
- Functional tests for all system components (flow, pressure, O₂, CO, SO₂, NOx, etc.)
- Comparison against a certified reference method
- Determination of calibration functions for pollutant concentrations
- Evaluation of measurement ranges, deviations, accuracy, and overall reliability
- Full regulatory calibration report
AST – Annual Surveillance Tests
- Stability checks
- Drift tests
- Zero and span verification
- Analyzer functional tests
- Comparison against reference values
Additional Tests Depending on System Type
- Optical analyzers (NDIR, UV, FTIR)
- Electrochemical analyzers
- Particle measurements (ISO and EN methods)
- Moisture, temperature, pressure, gas flow, and velocity measurements
Methods, Standards, and Accreditations
- EN‑14181 – European standard for CEMS calibration
- Ministry of Environmental Protection requirements:
- Stack Sampling Protocol
- CEMS Calibration Protocol
- Reference method testing according to EN and EPA standards:
- NOx – EN 14792 / EPA 7E
- SO₂ – EN 14791 / EPA 6
- CO – EN 15058 / EPA 10
- Particulates – EN 13284 / EPA 5
- VOC and TOC – EN 12619 / EPA 25A
- Physical measurements – EN 13284‑1, EN ISO 16911
All tests are conducted by certified technicians using advanced measurement equipment and full documentation suitable for regulatory submission.
“Regulatory fees, reporting requirements, and compliance obligations in this field continue to expand; therefore, professional, accurate, and well-documented calibration is an essential prerequisite for the proper operation of any facility equipped with a stack and a continuous emissions monitoring system.”
Industries Requiring CEMS Calibration
- Power generation and energy industries
- Chemical and pharmaceutical industries
- Combustion and steam generation facilities
- Refineries
- Food industry
- Waste‑to‑Energy facilities
- Metals, coatings, chemicals, and plastics industries
- Cement, asphalt, and quarry plants
- Waste and RDF processing facilities
Professional Support by Ecological Laboratories A.P. Ltd.
- Planning, preliminary inspections, and system surveys
- QAL2 and AST at the facility site
- Accredited analytical laboratory testing
- Interpretation of results and engineering recommendations
- Support in regulatory preparation
- High availability and ongoing professional assistance
- Complementary stack testing when required
This ensures compliant, reliable, and valid monitoring data and uninterrupted industrial operations.
Expertise in CEMS Calibration
Ecological Laboratories A.P. Ltd. combines engineering expertise, professional knowledge, and strict adherence to international standards, providing full calibration services including QAL2, AST, reference method testing, accredited analysis, and regulatory‑ready reporting.
Frequently Asked Questions
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What is the difference between QAL2 and AST?
- QAL2 is a full five‑year calibration against reference methods, while AST is performed annually to ensure stability.
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Is calibration mandatory?
- Yes. All CEMS installed under emission permit requirements must be calibrated according to EN‑14181.
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Who may perform CEMS calibration?
- Only accredited laboratories certified for the relevant standards and protocols.
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What happens if results are not valid?
- Non‑valid results may cause regulatory delays, repeat testing, or enforcement actions.
