A proficiency test to check
density calculations This proficiency test aims to
check the density calculations/conversions of the participants.The scheme was
organised before and in that final the following was concluded: 'In general the results
are an eye-opener. In practice, the spread in the results will be the sum of the
measurement and the conversion. And most probably the spread caused by the measurement
will be much larger than the spread in the conversion, which should be close to zero.
However, the spread in the conversions only, as observed in this study, is far from zero
and sometimes even larger than the requirements of the Standard. Furthermore a large
number of uncorrect results - results that deviated more than 0.0001 kg/l from the
theoretical value - was reported. For some exercises, this number of uncorrect results is
even over 65% of the total amount of results'. This proficiency test Density deviates from regular I.I.S. schemes in two ways: - it is organised on special request of a third party. Therefore, in contrast to regular I.I.S. proficiency tests, this scheme is not open to all interested laboratories, but only for those invited to participate; for those laboratories participation is even mandatory.
- the PT is a paper Round Robin for Density calculations/conversions. So, no samples are distributed, but a number of pages containing the data on density calculations.
On 20 Oct. 98 the proficiency test started with 114 participants out of 52 different countries. The
participants were sent four pages containing the data for this paper PT scheme (no sample
was sent). Most laboratories received the pages and additional instructions via electronic
mail (e-mail); some laboratories could not be reached in this way and to them the mail was
sent by post. They were requested to let a technician calculate the densities, to report
the calculated densities, applied corrections and tables on the forms and to return the
completed forms via airmail (and/or fax) to the Institute. The deadline for reporting results is set on 20 Nov. 98. A laboratory that sends in results after deadline will definitely will not get direct feedback in case any of its results are suspect! So be in good time to get the most out of this proficiency test. |