Review of EURAMET Calibration Guideline No. 18: Guidelines on the Calibration of Non-Automatic Weighing Instruments

Project Description

The EURAMET Calibration Guidelines No.18 is a document broadly used, not only by calibration laboratories but also by users of non-automatic weighting instruments. This guide is not only used in Europe, it has also been adopted by SIM and is being used other countries all around the world.
In most European countries it has been used as a reference document for the accreditation bodies in order to assess laboratories for the calibration of non-automatic weighing instruments. The interpretation of this document for the accreditation bodies has varied more or less among countries. The result has been a lack of harmonization though Europe related to non-automatic weighing instrument calibration. Stakeholders have asked to TC mass to review the guide and propose way to solve this situation as well as to include some missing issues.
The goal of this project is to review the guidelines in order to include some missing topics (such as the minimum sample weight), to make it more useful and practical and clarify some aspects so that harmonization can be achieved.

Final Report 2015-11-01

The purpose of the guide,from the field ‘Mass and Related Quantities’,is to enhance the equivalence and mutual recognition of calibration results obtained by laboratories performing calibrations of non-automatic weighing instruments. It contains advice on general aspects of calibration, measurement methods and results, including uncertainty of measurement, the calibration certificate and the use of mass or conventional mass values.
EURAMET’s Calibration Guide No. 18 was first published more than 10 years ago and has been regularly updated since then. The guide has become one of the most requested documents provided by EURAMET.It was adopted by other Regional Metrology Organisations and is widely used by accreditation bodies as a mandatory document.This latest update is the first review involving direct collaboration with balance manufacturers.
Important improvements of the new version include:clarification in the use of substitution loads, calculation for the eccentricity test, a more accurate formula for uncertainty related to the correction for air buoyancy, better approximation for air density variation, improved approximation methods, determination of minimum weight and better understanding of the effect of balance adjustment.There are no changes to the underlying calibration procedures.

The 4th edition of the EURAMET Calibration Guide No. 18 was developed thanks to the cooperation of Stuart Davidson (NPL, United Kingdom), Klaus Fritsch (Mettler Toledo, Switzerland), Matej Grum (MIRS, Slovenia), Andrea Malengo (INRIM, Italy), Nieves Medina (CEM, Spain), George Popa (INM, Romania) and Norbert Schnell (Sartorius, Germany).

See overview Calibration Guidelines

Progress Report 2015-04-21

During last TC Mass meeting a special session about this project was celebrated. The review is the final phase. One issue from appendix C and example are the only remaining issues.

Progress Report 2013-03-25

During last TC Mass meeting a special session about this project was celebrated. It was achieved to review until chapter 6 (included) except the issues about multi range instruments. Further meetings are required to go on with the review and the subsequent discussions.

Progress Report 2012-03-15

During last TC Mass meeting a special session about this project was celebrated. The main conclusions of the meeting are:Three new institutes have joined the project: SP, EIM and UME.

  • The aim of the review will be the improvement of the guide without any modification of the technical procedure.
  • In this review more practical examples will be included with an appropriate uncertainty budget table (according to EA 4-02).
  • A document with the changes between versions will be elaborated in parallel.
  • Before the 1st of June the partners should send their comments and proposals to the coordinator.
  • Before the 1st of July the coordinator will send a document that will include all the proposals.
  • PTB Braunschweig will organise a workshop to discuss the guide review.

On the other hand it has already been indicated in the EURAMET website that this guide is under review.


Further Information

Mettler-Toledo and Sartorius will collaborate in this project as stakeholders.