Practical Guide to QAL3: CMM AutoQAL Makes QAL3 Easier and More Cost-Efficient
The complexities of QAL (Quality Assurance Level) procedures for continuous emissions monitoring equipment and the EU Directives behind them can be cumbersome to grasp for any emissions monitoring operator. Quality assurance is closely connected to the EU Standards EN 14181 and EN 15267 (QAL1), and in this article we will look into the details of QAL3, which can now be done a lot easier, thanks to our new continuous mercury monitoring system CMM AutoQAL with an EN 15267 certified, integrated and automatic QAL3 Validation Tool. Read on to find out more about the new device, and QAL3 in general.
What Does QAL3 Mean?
QAL3 is the on-going quality assurance process of a continuous emissions monitoring system.
According to the EN 14181, the aim of QAL3 is to maintain and demonstrate the quality of a CEMs, so that the requirements for the stated zero and span repeatability and drift values are met during ongoing operation and the CEMS is maintained in the same operational condition as when installed and calibrated in QAL2.
In practice, QAL3 procedures mean CEMs zero and span gas drift check and control. Process operators and CEM owners are responsible for carrying out the QAL3 procedures
How Is QAL3 Typically Carried Out?
Usually, QAL3 is carried out by feeding the zero gas (typically Nitrogen) and span gas through entire emissions monitoring system and monitoring the measuring results of zero and the span gas. This gives us valid and reliable information on the drift and precision and confirms proper operation of the CEMs.
QAL3 measurement in emissions monitoring systems can mostly be done automatically, which saves time and reduces costs for the plant operators. It is also important to carry out the QAL3 measurements as time-efficiently as possible in order to minimize any downtime of the emissions monitoring system.
No External Measuring Equipment Needed with CMM AutoQAL
In our new device CMM AutoQAL for continuous Mercury monitoring, the fully integrated, EN 15267 certified QAL3 validation tool enables automatic span/zero gas input and all QAL3 measurements and control according to EN 14181. Previously, external tools and equipment were needed for the test gas input, but with CMM AutoQAL external measuring instruments are no longer required.
QAL3 Measurements and Approval Limits
In short, the results of QAL3 measurements are monitored and examined against approval limits. The approval limits can be set according to the EN 15267 QAL1 certification test results, or the maximum permissible uncertainty limits, which are defined in the IED, Industrial Emissions Directive. If the QAL3 inspection exceeds these limits, the emissions monitoring system needs to be maintained or repaired.
QAL3 inspections are done according to the EN 14181 and they need to be documented. QAL3 results and information about any possible repair work done in the case of exceeding the approval limits need to be available for the QAL2 and AST measurements.
The minimum timespan for the frequency of QAL3 measurements is predetermined by the EN 15267 certifications tests, i.e. in QAL1. A field test is included in the QAL1, and the length of a successful field test dictates the length of the maintenance interval. The longer the field testing lasts, the longer the maintenance interval of a CEMs is.