The following information is a synopsis of the requirements of the Directive. It is not an area in which we currently offer advice but you may find some useful links here.

Measuring Instruments directive

Latest Developments

The new Measuring Instruments Directive(2014/32/EU) has been published to bring it into line with the New Legislative Framework (NLF). It came into force on the 20th April 2016 immediately replacing the previous Directive without a transition period. This will have little effect for manufacturers.


The Measuring Instruments Directive (MID) 2014/32/EU is a New Approach Directive which applies to a large range of measuring instruments, with the goal of creating a single market in measuring instruments throughout the EU. It establishes the essential requirements that the measuring instruments will have to satisfy if they are subject to legal metrological control in a Member State and the conformity assessment that they have to undergo prior to their placing on the market and putting into use.

The Directive also aims to harmonise the requirements of the various types of measuring instruments, as fas as practicle, and as such repeals the following Directives;

  • Directive 71/318/EEC (gas meters)
  • Directive 71/319/EEC (meters for liquids other than water)
  • Directive 71/348/EEC (meters for liquids other than water - ancillary equipment)
  • Directive 73/362/EEC (material measures of length)
  • Directive 75/33/EEC (cold water meters)
  • Directive 75/410/EEC (continuous totalising weighing machines)
  • Directive 76/891/EEC (electrical energy meters)
  • Directive 77/95/EEC (taximeters)
  • Directive 77/313/EEC (measuring systems for liquids other than water)
  • Directive 78/1031/EEC (automatic checkweighing and weight grading machines)
  • Directive 79/830/EEC (hot-water meters)
  • Directive 75/33/EEC (cold water meters) is a special case as it has only been partially repealed for meters defined in Annex MI-001 of the new Directive (for clean water meters, for example in residential areas, commercial or light industrual use).

The Directive applies to the devices and systems with a measuring function defined in the following instrument-specific annexes MI-001 to MI-010 (i.e. not all measuring instruments are within the scope of the Directive);

  • MI-001 - Water meters
  • MI-002 - Gas meters and volume conversion devices
  • MI-003 - Active electrical energy meters
  • MI-004 - Heat meters
  • MI-005 - Measuring systems for continuous and dynamic measurement of quantities of liquids other than water
  • MI-006 - Automatic weighing instruments
  • MI-007 - Taximeters
  • MI-008 - Material measures
  • MI-009 - Dimensional measuring instruments
  • MI-010 - Exhaust gas analysers

A measuring instrument must meet the essential requirements laid down in Annex I, applicable to all instrument types, and in the relevant instrument-specific Annex of the Directive. The general requirements cover the following aspects;

  • Allowable errors (including specifications of the intended climatic, mechanical and electromagnetic environment the instrument has been designed for)
  • Reproducability
  • Repeatability
  • Discrimination and Sensitivity
  • Durability
  • Reliability
  • Suitability
  • Protection against corruption
  • Information to be borne by and accompany the instrument
  • Indication of result
  • Further processing of data to conclude the trading transaction
  • Conformity evaluation

The directive contains several requirements concerning software. Namely, software that is critical for the metrological characteristics shall be identifiable, shall be secured, shall not be inadmissibly influenced by other software and shall be adequately protected against accidental or intentional corruption. It is the manufacturersí decision how the software might meet the MID requirements, but a guide has been published by WELMEC to assist manufacturers, examiners and inspectors. This is available from the WELMEC web site.

A technical file shall be produced that renders the design, manufacture and operation of the measuring instrument intelligible and shall permit an assessment of its conformity with the appropriate requirements of the Directive. Depending on the assessment method chosen to demonstrate compliance with the Directive, the technical file may require more or less information ñ for example; details of manufacturing procedures to ensure consistent production, descriptions of electronic devices with drawings, diagrams, flow diagrams of the logic and general software information, design calculations, EC-type examination certificates.

With respect to the electromagnetic compatibility of the instrument, the immunity requirements are specified in the relevant instrument-specific annex of the MID. The emissions requirements, however, are as specified in the EMC directive 2004/108/EC.

Demonstration of conformity

The demonstration of conformity should be carried out by the application, at the choice of the manufacturer, of one of the conformity assessment procedures listed in the specific annex concerning that instrument. The conformity assessment modules which make up the procedures are described in annexes A to H1 of the Directive.

The manufacturer shall also provide, where appropriate, technical documentation for specific instruments or groups of instruments as set out in the Directive. Not all modules or methods of assessment involve a notified body.

The implementation of the Directive into UK law has been entrusted to the National Weights and Measures Laboratory (NWML), working with Ofgem and the Department for Transport. More information regarding the MID, especially with regard to consultation documents and industry responses can be found on their web site at the following address:

Links to the directives repealed by the MID, and an alternative summary of the MID, can be found on the Europa web site.

measuring.txt · Last modified: 2018/06/04 10:41 by Sarah Hall
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