Below are links to various articles and videos about metrology. They are worth reading and viewing.
This article contains several videos about the redefinition of the units. A turningpoint for humanity: redefining the world's measurement
SI unit Kilogram
Interesting article. don't forget to click on the link. "Learning with: the kilogram is dead, long live the kilogram."
Good movie about the silicion sfere with dutch subtitles World's roundest object
SI unit Meter
SI unit Kelvin
SI unit Second
SI unit Mol
Two movies about the mole. The mole
Calibrating a Micropipette
On 4 april 2018 CALLAB Magazine published my contribution on pipette calibration.
This paper discusses the calibration of pipette, with particular attention to the type that is used and calibrated most frequently. This is the so-called air-displacement pipette, single channel, adjustable volume pipet. The new ISO/IEC 17025, published November 2017, demands more attention to the agreement of the calibration procedure with the customer. The paper describes points that need to be agreed with the customer and calibration by the gravimetric method (weighing). The alternative calorimetric method (ISO 8655-7) is not described in this paper. Read the full article (PDF)
The new ISO/IEC 17025:2017
The Final Draft International Standard of ISO / IEC 17025 has been approved. A number of things have already been written about the requirements for the general management system by the new standard. Here we set a few points for attention.
Important changes have to do with the structure of the standard, the so-called high level structure. Unfortunatelly it is not really classified in that overarching classification. When writing this standard, more attention was paid to the other accreditation standards that have been written or adapted since the establishment of the high level structure. Just like ISO 9001, this standard also requires that a laboratory must map and manage risks. This concerns risks relating to independence (4.1), but also risks of deviations/non-conformities during the technical execution (7.10). Risks that may affect the validity results must be identified.
The standard is somewhat updated to the use of computers and software by a separate requirement for laboratory information systems (LIMS). For the rest, the requirements in the new standard are not much different from the current version.
The requirement for traceability is summarized in one standard element 6.5 and explained in appendix A to the standard.
For calibration laboratories, the change in approach to testing conformity with specifications is also important (7.8.6). The new standard speaks of a decision rule that has been agreed with the customer and that must be used to test specifications. There are then several possibilities to test the specifications, but the method used must be agreed with the customer; must be recorded and the laboratory must have considered the risk of a false conclusion.
For more information see this article in CALLAB magazine.RvA has published a cross-reference table in its introduction document RvA T049 of the ISO/IEC 17025:2017. The table also discusses the differences between the old and new ISO/IEC 17025. Compare the table with the UKAS table. An overview of the UKAS approach is given in this link.
Our course metrology, traceability and uncertainty already deals with the new standard and the adjustments for calibration and test laboratories.