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Download the final PT report (iis14L04) on Used Lubricating Oil

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Summary of the proficiency tests:

On 22 August 2014, the PT report on Used Lubricating Oil was finished. The proficiency test started on 21 May 2014 (see message "Proficiency Test on Lubricating Oil started" on this website) when the samples were distributed.

In this interlaboratory studies 97 participants in 52 different countries have participated.

The participants were requested to perform the following tests: Acid Number, Base Number, Density@15°C, Kinematic viscosity @40°C, Kinematic viscosity @100°C, Flashpoint, Water and 20 elements (wear metals and additives: Ag, Al, Ba, Ca, Cr, Cu, Fe, Li, Mg, Mn, Mo, Na, Ni, P, Pb, Sn, Si, Ti, V and Zn. 

The proficiency test report summarises per test, the test results, the analytical methods reported by the participants and the z-scores calculated for each participant are tabulated. Also, for each test, the calculated summary (e.g. mean, standard deviation and reproducibility) is given.

In the report also an evaluation of the test results is given. Problems encountered in the analyses are mentioned and - where possible - suggestions for quality improvement are formulated. For each test a comparison is made between the results of the group of participants and the requirements given by the relevant standard (e.g. ISO, DIN, ASTM).