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Australian Government: National Measurement InstituteAustralian Government: National Measurement Institute
National Measurement Institute

Pattern Approval

Pattern approval is the process whereby an impartial body examines the pattern (design) of an instrument prototype against a published national standard. This determines whether an instrument is capable of retaining its calibration over a range of environmental and operating conditions and ensures that the instrument is not capable of facilitating fraud. It is a means of determining the quality of the instrument.

Pattern approval (in other countries this is sometimes called 'type approval') is mandatory for measuring instruments used for trade in Australia. The National Measurement Institute (NMI) evaluates measuring instruments to check they meet specific Australian standards. When an instrument is successfully submitted for approval, that particular pattern or type is approved and a certificate of approval is issued.

The pattern approval certificate permits the measuring instrument to be verified and then used for trade, or other legal purposes.

The pattern approval examination process to test the pattern or design of an instrument involves:

  • assessment of the instrument documentation
  • assessment of the operation of the instrument against requirements - which are usually based on international recommendations published by the International Organisation of Legal Metrology (OIML)
  • performance testing to ensure that the instrument performs as intended (i.e. to within allowable maximum permissible errors) over a range of environmental and usage conditions specified in the requirements.

Here are the steps commonly associated with the pattern approval process conducted by NMI.

Flow chart showing steps in pattern approval process

Collapsed - What we approve

We issue Certificates of Approval for:
instruments including, but not limited to:

  • length measuring instruments
  • area measuring instruments
  • spirit dispensers
  • automatic tank level gauges
  • alimentary product flowmeters (milk, beer)
  • fuel dispensers for motor vehicles
  • (bulk) liquid-measuring systems
  • non-automatic weighing instruments
  • automatic weighing instruments
  • milk tanks
  • vehicle tanks
  • liquefied petroleum gas systems
  • compressed natural gas systems
  • multi-dimensional weighing instruments
  • utility (gas, electricity and water) meters
  • grain protein measuring instruments
  • polarimetric saccharimeters
  • evidential breath analysers
  • digital indicators
  • load cells
  • fuel dispenser control systems
  • fuel dispenser calculator/indicators
  • point of sale (POS) systems.

We approve these instruments, but we appoint approving authorities to test them

  • utility (electricity and water) meters
  • evidential breath analysers

We can also issue OIML certificates of conformity to assist with international approval. These certificates are accompanied by a test report, and state that the instrument evaluated complies with the requirements of an OIML recommendation for patterns of instruments in use for trade. We issue OIML certificates for:

  • continuous totalising automatic weighing instruments
  • automatic catchweighing instruments
  • load cells
  • non-automatic weighing instruments
  • automatic rail weighbridges
  • measuring systems for liquids other than water.

Collapsed - Acceptability of Overseas Pattern Approvals

If pattern approval for a measuring instrument has been issued in another country, NMI can accept certain test results (please note that we do not normally accept manufacturer's test results). To allow us to determine acceptability we require:

  • Certificate of approval (if applicable).
  • Documentation folder (if applicable).
  • Full detailed test report including test results.
  • Details of the laboratory where the testing was carried out, if not part of a formal mutual acceptance agreement, including its ISO 17025 certificate of accreditation.

NMI has mutual acceptance agreements with:

  • National Weights and Measures Laboratory in the United Kingdom, on the mutual acceptance of test reports for load cells, non-automatic weighing instruments and fuel dispensers (excluding liquefied petroleum gas)
  • Netherlands Measurement Institute, on the mutual acceptance of test reports for load cells, non-automatic weighing instruments and fuel dispensers (excluding liquefied petroleum gas)
  • New Zealand Ministry of Consumer Affairs, on the mutual acceptance of test reports for non-automatic weighing instruments.
  • Countries participating in the multi-lateral OIML agreement.

Collapsed - How to apply

Pattern Approval Procedures

  1. The first step is to look at the pattern approval requirements and the pattern approval guidelines and procedures relevant to your instrument. This information is listed by category of instrument, for example beverage dispensers, under Pattern Approval Specifications by Instrument and Industry.
  2. Once you are familiar with the requirements associated with your measuring instrument, collate all the documents, including for example; details of the instrument, model number, capacities, operator manuals, technical manuals, circuit diagrams, board layout diagrams, parts lists and mechanical overview (exploded views), and proposed sealing method/s and nameplate layouts.
  3. We recommend you then complete the pattern approval checklist. Your application will still be processed without this but filling it in may reduce the time (and fees) required to carry out the assessment.
  4. The next step is to complete the pattern approval application form. This form can be submitted via:
  5. New clients: please also complete the credit application form.
  6. When we receive your application we will despatch an acknowledgement email, advising that your application has been prepared for assessment.
  7. Please note, NMI usually requires the instrument to be submitted, although site visits are possible for large instruments.
  8. An initial assessment is carried out to determine that all relevant information (see step 2) and a suitable sample instrument (if requested by NMI) have been supplied, to enable the full pattern approval assessment/evaluation/testing to begin.
  9. If the full the assessment is successful, NMI will issue a certificate of approval, which contains a pattern approval number.
  10. Production instruments must be:
    • constructed as described in the documentation lodged with NMI, the certificate of approval and the technical schedule
    • marked with the pattern approval number
    • verified prior to use for trade.
  11. NMI requires certificates of approval to be reviewed every five years to ensure compliance with current legislative and technical requirements. Certificates include a date at which the review becomes due (approximately 5 years after the pattern is approved) but the approval remains valid even after the review date has been reached. 

Collapsed - What happens after pattern approval?

Next stage after Pattern Approval

Pattern approved measuring instruments must be “verified” before they are used for trade. Verification involves testing an instrument in situ to ensure that it operates correctly.

Verification is the process whereby an instrument is:

  • inspected to ensure that it complies with the approved pattern
  • calibrated to ensure that it is operating within the maximum permissible errors
  • marked to indicate that verification has occurred.

Verification is carried out by an NMI-appointed servicing licensee with an appropriate licence class for the instrument that they are verifying.

Information on servicing licensees.

A servicing licensee can only verify a measuring instrument that:

  • has been pattern approved
  • is compliant with the Certificate of Approval
  • has a data plate with the relevant markings.

A verification mark will be placed on the instrument at the conclusion of the verification process.

You may be interested to know that servicing licensees must follow the National Instrument Test Procedures (NITPs) when performing verifications.

Are there other requirements I need to be aware of?

General Certificates

If your Certificate of Approval allows you to connect an auxiliary device, such as a printer or fuel dispenser nozzle, it may include a reference to a General Supplementary Certificate of Approval.

If such a device is being supplied to third parties with your instrument, you must ensure that it complies with the relevant general certificates and is marked appropriately.

Auxiliary devices are not required to be assessed for pattern approval.

Other Regulations

Information about requirements such as the installation of a measuring instrument, or what accuracy class can be used for a particular application e.g. approaches for weighbridges and licensing for public weighbridges can be found under the Trade Measurement section of our website.

Special Clauses

Some Certificates of Approval include special clauses which may require additional action, such as advising NMI of instrument locations or providing copies of test results.

Please forward this information to NMI by email:

Changes to Certificates

If you make any changes to the design of the instrument after the certificate of approval is issued, you are required to notify NMI. Changes may require a variant to be added, or other amendment made, to the certificate.

You must also notify NMI if your company or contact details change.


Certificates are normally required to be reviewed every five years. The review date is included on the Certificate of Approval. You will need to send an application when your certificate is due for review. The approval remains valid even after the review date has been reached.

Specific Exemptions

Australian law requires that every measuring instrument used for trade in Australia is pattern approved by NMI’s chief metrologist (scientist). Specific exemptions from the requirements may be applied, otherwise it is an offence to sell or use a measuring instrument for trade purposes in Australia that does not have an Australian certificate of approval.  

Frequently Asked Questions

Q1. Who can mark my pattern approval number on an instrument?

Only the submitter, or somebody authorised by them, may mark an instrument with the pattern approval number.

Q2. If I have an instrument approved for legal use only, can it be used for trade?

No. Some measuring instruments have been approved for legal use only, e.g. some weighing instruments. These instruments cannot be used for trade because they may have been assessed against different criteria and have different controls around their use.

Q3. Where can I find someone to verify my measuring instrument?

To find a servicing licensee to verify a measuring instrument, you can send an email to the Trade Measurement Licensing Team at Please include your location and the type of instrument you wish to have verified. NMI will provide details of servicing licensees in your area who may be able to help. NMI is not able to recommend specific service providers.

For more Information

For more information contact 1300 686 664 or