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.

Length, area and dimensional requirement documents

NMI M 1 Length measuring instruments

NMI M 3 Area measuring instruments

NMI R 129 Multi-dimensional measuring instruments

Volume and flow requirement documents

Dynamic

NMI M 2 Beverage dispensers

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 117 Measuring systems for liquids other than water

NMI R 118 Fuel dispensers for motor vehicles

NMI R 139 Compressed gaseous fuel measuring systems for vehicles

Static

NMI M 4 Milk tanks

NMI R 71 Fixed storage tanks for trade use

NMI R 80 Road and rail tankers with level gauging

NMI R 85 Automatic level gauges for measuring the level of liquid in stationary storage tanks

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 50 Continuous totalising automatic weighing instruments (belt weighers)

NMI R 51 Automatic catchweighing instruments

NMI R 60 Metrological regulation for load cells

NMI R 76 Non-automatic weighing instruments

NMI R 106 Automatic rail weighbridges

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

Utility meters (electricity, water and gas) requirement documents

NMI M 6 Active-energy electricity meters

NMI M 10 Meters intended for the metering of water in full flowing pipes

NMI M 11 Meters intended for the metering of water in open channels and partially filled pipes

NMI M 13 Active-energy electricity meters

NMI R 46 Active-energy electricity meters

NMI R 49 Water meters for cold potable water and hot water

NMI R 137 Gas meters

Quality (grain, cane sugar, wine grapes) requirement documents

NMI M 8 Protein measuring instruments for grain

NMI R 14 Self-indicating polarimetric saccharimeters graduated in accordance with the ICUMSA International Sugar Scale

Point of sale (POS) systems requirement documents

NMI M 7 Pattern approval specifications for point of sale systems

Guidance document for the pattern approval of point of sale systems

NMI M 5 Brake force measuring instruments

NMI R 126 Evidential breath analysers

More information

Find a general certificate of approval for instruments manufactured to a common standard
Pattern approval guidelines and procedures can help you with your pattern approval application
Find superseded pattern approval requirements on the OIML website
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