The Welmec Working Group 10 meeting focussed on relatively new developments such as the application of conversion tables for mixtures of fuels, and on long-standing issues such as the maximum permissible errors.
Application of conversion tables
The last decade has seen increased concern for the environment and alternative fuels. As a consequence, growing amounts of Ethanol and Bio-diesel are added to mineral fuels. Until recently, initiatives and/or agreement on application of conversion tables for mixtures of these fuels were on a national basis. The majority of attendees agreed to accept and apply the recently developed PTB data and equations to this effect, where national legislation permits. This is effectively the first time since the introduction of the new fuels/fuel mixtures that we have tables that are acceptable in a large number of EU Member States.
Maximum permissible errors
A long-standing issue in “Liquids other than Water” has been the applicable MPEs (maximum permissible errors) on measuring systems/instruments fitted with gas elimination devices. Interpretation differences originated from slight variations in the translation of the MID into the various official EU languages. The Working Group agreed that in applications where entry of air/gas/vapour is common practice and therefore part of the normal operating conditions, the MPE equals the regular MPE, typically being +/- 0.5%. Only in applications where the entry of air/gas/vapour is an exception (disturbance) is it permitted to accept an additional +/- 1.0%, resulting in +/- 1.5% for a typical application in case of disturbances.
OIML meeting together with Milestones in Metrology IV conference
The WG10 meeting was also attended by Mr. Ralph Richter, Secretary of the OIML group in charge of OIML R117-2 and R117-3. He announced plans to issue a second Committee Draft of R117-2/-3 in early 2012 and organise a full sub-committee meeting on 14–16 May 2012 in Venice, Italy, in conjunction with the Milestones in Metrology Conference. Confirmation on this schedule will follow in the next Newsletter.
