QAL2 & QAL3 testing
Your CEMS only produces data the Department of Environment will accept if it is quality-assured to the standard. We run the full EN 14181 quality chain — QAL2, QAL3 and the Annual Surveillance Test (AST) — so your emission monitoring stays accurate, calibrated and inspection-ready, all year round.
The EN 14181 quality chain, in practice
Malaysia's CEMS framework follows the international EN 14181 standard, which Mesra applies every day — we were a Technical Committee Member and Reviewer for the DOE CEMS Guidelines that put it into national practice. The standard defines four jobs, each answering a different question:
The CEMS quality-assurance chain · EN 14181
● Functional test must pass before QAL2 and AST
- QAL2 — is the system right on your stack? A certified analyser still has to be proven on your chimney, with your flue gas. We run Standard Reference Method (SRM) measurements in parallel with your CEMS, establish the calibration function that relates its signal to true concentration, and confirm variability is within allowed limits.
- QAL3 — is it staying right, day to day? The ongoing discipline of zero and span drift checks plotted on control charts, so a developing fault is caught long before it costs you a compliance breach.
- AST — the Annual Surveillance Test. The yearly independent check that confirms your QAL2 calibration still holds.
Why independence matters
Under EN 14181 the body that runs your QAL2 and AST must be independent of the party that installed the system — a tester cannot validate their own company's work. That independence is exactly what makes your calibration credible to the regulator. Mesra performs testing to this requirement, with traceable reference methods and full documentation.
What you receive
- A complete QAL2 calibration report with the calibration function and valid calibration range.
- Variability test results assessed against the limit values for your pollutants.
- A QAL3 procedure and control-chart setup your team can run between formal tests.
- AST scheduling so you never miss the annual deadline.
- Documentation packaged the way DOE inspections expect to see it.
Get the calibration range right
A frequent and expensive mistake is a QAL2 calibration that doesn't suit your daily Emission Limit Value. The certified and calibrated range must be appropriate for the limit you actually operate to — not just to a brand name. We check this before testing, so the result stands up to scrutiny.