Intelaboratory comparison tests of cement

In this paper results of interlaboratory tests applied on the construction product cement are presented, in which 15 laboratories had participated. The inter-comparison test was carried out in accordance with guidelines ISO/IEC 43-1, ISO/IEC 43-2 and ILAC-G13. Standard procedure for statistical analysis of test results and Z-score according to ISO 5725 was applied. The type of error or suspicious result can in many cases be deducted to a certain type of problem in the laboratory or with the method. So it is important to analyse results and to take needed corrective or preventive actions or measures for improvement laboratory performance works. The analysis of the performed interlaboratory test is presented, with the emphasis on detection of reason when getting suspicious results.