Laboratory ring test for particulate measurement systems according to VDA 19.1

What is a Laboratory Ring Test?

A laboratory ring test is a method of external quality assurance for measurement systems. Identical comparison samples are examined using the same procedures on different measurement systems. Comparing the results allows statements to be made about the measurement quality of the involved measurement systems.

Why participate in laboratory ring tests?

In-house laboratories are recommended to regularly verify their measurement systems within the framework of their quality management system and to include this in their quality management manual in accordance with DIN EN ISO 9001.

For accredited testing laboratories, it is mandatory to participate regularly in laboratory ring tests as part of government approval procedures. In the context of the standard DIN EN ISO/IEC 17025, annual participation is even recommended. This is to ensure the quality of their results and to demonstrate their competence.

How much does participation cost?

The fee for a measurement system wishing to participate in the laboratory ring test is 550 euros plus VAT, for CEC members 300 euros plus VAT. Other participating measurement systems receive a discount. Please contact us regarding this. Additionally, we charge a one-time travel flat rate of 0.30 euros/km for round-trip between CEC Leonberg and the participant's address to deliver the comparison sample for analysis.

When is the laboratory ring test conducted?

Currently, CEC offers one laboratory ring test per year. A ring test begins once the minimum number of measurement systems has been reported, but not earlier than the start of the specified execution period. Therefore, it is important to register in a timely manner.

Registration and documents

The next laboratory ring test will start in April 2023.

How does the laboratory ring test work?

1. A laboratory registers its various measurement systems*, regardless of the manufacturer, for the ring test.
2. A test filter is provided to the laboratory within the framework of the ring test, which is tested for each registered measurement system according to the standard analysis of VDA 19 Part 1.
3. The data from all participants are confidentially evaluated by the independent provider Cleaning Excellence Center.
4. Each participant receives an anonymized result report for each registered measurement system, comparing their own results with those of others and evaluating them based on the z-score assessment according to DIN 38402-A45.
5. This enables the participant to identify and eliminate potential weaknesses.
6. Each measurement system that participates successfully receives a CEC plaque, which immediately indicates to auditors when the last laboratory ring test was conducted on this measurement system.

* A measurement system in the Cleaning Excellence Center's ring test is defined as a photometric measurement instrument and the person performing manual re-inspection. Stereo microscopy systems, zoom microscopy systems, material microscopy systems, and flatbed scanners are permitted for the ring test.

The measurement instrument must meet the necessary requirements to fully perform the standard analysis of VDA 19 Part 1. This ensures that the laboratory ring tests are conducted independently of the manufacturer and in accordance with VDA 19 Part 1.