NMI issues OIML certificates and certificates of approval of measuring instruments.
Note: NMI also issues instrument test reports which are based on the performance of a module or a complete instrument. An instrument test report generally involves accuracy tests only, performed under the conditions specified by the applicant. Instrument test reports are only available to the applicant. An instrument test report does not imply approval for trade use but may be useful to assess the performance of the equipment.
OIML certificates
The Chief Metrologist is a registered notifying body for issuing OIML certificates of conformity. These certificates are accompanied by a NATA endorsement certificate and test report, and state that the instrument evaluated complies with the requirements of an OIML recommendation for patterns of instruments in use for trade. OIML certificates may be issued for:
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continuous totalising automatic weighing instruments
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automatic catchweighing instruments
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metrological regulation for load cells
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non-automatic weighing instruments
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automatic rail weighbridges
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measuring systems for liquids other than water
Certificates of approval of measuring instruments
Under Regulation 60, NMI issues certificates of approval to certify that the measuring instrument is suitable either for use for trade or as a legal measuring instrument (i.e. if it is required by a government authority to be used for regulatory purposes).
Certificates of approval are usually comprised of three sections:
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a certificate which consists of the advice of approval together with the conditions of approval
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a technical schedule (which may include illustrations) which describes the pattern and any variants
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a test procedure which specifies the tests to be performed for verification or certification of instruments conforming to the pattern and its variants and the applicable maximum permissible errors
A new certificate of approval and technical schedule are issued for each variant to the pattern subsequently approved. For more information refer to NMI P 106.
You may obtain copies of our certificates of approval by clicking here.
Supplementary certificate of approval
A supplementary certificate is issued when a component of a pattern is submitted for approval and, after examination, is found to comply with the design specifications for that component.
Provisional certificate of approval
A provisional certificate may be issued for a period of up to twelve months where, because of its large size, installation requirements or other features, the pattern of the instrument cannot be fully examined in the laboratory and therefore requires field-testing.
General certificates
A general certificate is issued to cover trade measuring instruments that are capable of being manufactured to a common standard. In a general certificate a set of design and/or installation parameters are specified. General certificates are issued:
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for particular categories of simple measures which are submitted directly to trade measurement authorities for verification without examination or which may be certified by a licensed certifier
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to complement certificates of approval by providing general data and calculations, installation requirements and other information; such general certificates do not replace the need to obtain a certificate of approval of a measuring instrument
General supplementary certificates
General supplementary certificates are issued to supplement certificates of approval by approving ancillary or peripheral modules, for example printers and electronic cash registers.
Instrument certificate of approval
An instrument certificate is issued when the instrument under examination is uniquely designed for specific operating conditions and is not covered by any existing design specifications.
Conversion certificate of approval
A conversion certificate allows the applicant to convert instruments covered by a certificate of approval to a different type of instrument if that conversion is in accordance with a relevant general certificate. A conversion certificate describes a pattern and a general certificate allows variants to that pattern.
Variation to a certificate of approval
A variation to a certificate of approval is required when an applicant changes or adds a pattern component (a variant) that alters the approved performance or operation of an approved pattern.
Interim certificate
An interim certificate, valid for up to three months, is issued on completion of a successful approval examination, to enable an instrument to be submitted for verification by trade measurement authorities prior to the issue of the certificate of approval.
Notification of change to certificates of approval
Minor changes to approval documents such as changes in markings, clarification of descriptive material, alteration to periods of validity and other administrative matters, shall be notified by means of a notification of change (change notice). A notification of change may be issued for any type of certificate.
Cancellation of certificate of approval
A cancellation certificate may be issued to cancel an approval or series of approvals. After the cancellation date, no new instruments conforming to the pattern or variants described in the certificate may be submitted for verification or certification. However existing instruments may continue in use at the discretion of the trade measurement authority.
Withdrawal of certificate of approval
All instruments shall be removed from use for trade after a withdrawal certificate has been issued for the certificate under which they were approved.