This page belongs to: National Measurement Institute

Pattern approval requirements

During the pattern approval process, we examine the design of an instrument. To comply, the instrument pattern must meet its related mandatory requirements.

Requirements are either:

  • prefixed with ‘NMI R’ and based on an International Organization of Legal Metrology (OIML) recommendation of the same name and number
  • prefixed with ‘NMI M’ and have been prepared by the National Measurement Institute (NMI).

For accessible versions of these documents, email our pattern approval section.

NMI R 129 Multi-dimensional measuring instruments

Volume and flow requirement documents


NMI R 81 Dynamic measuring devices and systems for cryogenic liquids

NMI R 105 Direct mass flow measuring systems for quantities of liquids

NMI R 125 Measuring systems for the mass of liquids in tanks

Mass and weighing requirement documents

NMI R 33 Conventional value of the result of weighing in air

NMI R 51 Automatic catchweighing instruments

NMI R 106 Automatic rail weighbridges

NMI R 107 Discontinuous totalising automatic weighing instruments (totalising hopper weighers)

Point of sale (POS) systems requirement documents

NMI M 7 Pattern approval specifications for point of sale systems

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