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National Measurement Institute
      

Weighing Instruments

The Licensing team is pleased to provide you with an update on topics relevant to your work as a servicing licensee.

We welcome your feedback and urge you to contact us with your ideas or queries. This will help us to prepare future updates. Contacting us is easy!

Simply call our hotline: 1300 686 664 (press option 2) to talk directly to one of our licensing officers or email us at tmlicensees@measurement.gov.au

 

Legislative requirements

The National Measurement Act 1960 sets out the requirements for verifying a measuring instrument:

  • the measuring instrument must operate within the limits of error permitted under the regulations
  • the measuring instrument must be of an approved pattern.

 

Collapsed - Do I need permission from NMI to place labels advertising my business on verified measuring instruments?

No. Verified trade measuring instruments can have additional information or advertising material as long as the identifier cannot be confused with the verification mark. It is an offence under Section 18GO of the National Measurement Act 1960 to mark a measuring instrument with a mark likely to give an impression that it is a verification mark.

Additional identifiers are not regulated under the Act and can come in many forms including labels, tags or stamped information. Identifiers including any of the following words – verified, verification, certified or certification, or those that mimic the format of the verification mark, will be considered a breach of the Act. To avoid confusion by the user of the instrument, a statement such as 'this is not a verification mark' on the identifier is suggested. The format of verification marks is covered in the information

Refer to the General Principals for placement of verification marks and labels.

Collapsed - General principles for verifying instruments with alternative load receptors

Licensees are sometimes asked to verify non-automatic weighing instruments with a load receptor that is different to load receptors detailed in the relevant Certificate of Approval. This alternative load receptor may have been supplied by the manufacturer or modified to suit particular business needs of clients to. Such modifications include adding scoops or rollers to the original load receptor or replacing the load receptor with a different type of receptor.

A non-automatic weighing instrument is still considered to be of an approved pattern after a modification has been made to the load receptor provided the following general principles are satisfied:

  • The modification does not affect the measurement performance of the instrument.
  • The instrument is capable of meeting all of the relevant requirements in the National Instrument Test Procedure (NITP) including accuracy, repeatability and eccentricity
  • The design shall allow for completion of the NITP tests including the eccentricity test appropriate for the modified instrument.
  • The load receptor is stable and is not tilted during loading or weighing.
  • The load receptor transmits the weight of the load to the load-measuring device in a manner that is consistent with the requirements of the relevant Certificate of Approval.
  • The weight of the alternative load receptor plus the maximum capacity of the weighing instrument must not exceed the capacity of the load cells.
  • The weight of the alternative load receptor is within the initial zero setting range of the instrument.
  • Modifications that do not form part of the alternative load receptor shall not overhang the load receptor, e.g. rollers to facilitate loading.
  • Removable load receptors that are not symmetrically loaded shall only locate in a single orientation. The modification shall not cause excessive eccentric loading of the weighing instrument:
    • The centre of gravity for the modification shall be located approximately in the centre of the load receptor.
    • No part of the modification shall overhang the area of the original load receptor.
  • The instrument is re-verified after the modification.

Collapsed - Re-verification as a result of adjustment or repair

The information below will help verifiers to decide whether a measuring instrument needs to be verified after adjustment or repair.

Non-compliance issues that are not considered to affect metrological peformance of measuring instruments:

  • Environmental parameters outside those permitted in the certificate of approval.
  • Faulty auxiliary indicating or printing device.
  • Faulty keypad buttons.
  • Faulty LCD displays - missing segments.
  • Incomplete details on instrument display (missing decals).
  • Incorrect, incomplete, illegible or missing data plate.
  • Unstable installation - instrument not securely fixed.
  • Faulty level bubble.
  • Faulty zero indicating device.
  • Missing or broken levelling feet.
  • Non-compliant weighbridge approaches.

Re-verification will not be required. After repair the instrument can be used for trade.

 

Non-compliance issues that are considered to affect metrological peformance of measuring instruments:

  • Faults in electronic circuit boards.
  • Faulty LCD displays - unreadable.
  • Incorrect software version in use.
  • Price computing errors.
  • Accuracy, eccentricity and repeatability errors in excess of the MPE.
  • Accuracy of zero and tare setting.
  • Exceeds permitted discrimination/sensitivity.
  • Faulty zeroing device.
  • Zero shift in excess of MPE.
  • Belt weighers and automatic totalising hopper weighers operating outside flow rate range.

Re-verification will be required. The previous verification mark must be removed or obliterated and after adjustment or repair the instrument must be re-verified.

Collapsed - NAWI: Under NMI R76 scales must be level when in use

We have recently had inquiries about applying notices to weighing instruments to remind users they need to keep their weighing instruments level.

Licensees and verifiers will be aware the NAWI National Instrument test Procedure (NITP) requires an instrument to be level when conducting a test for verification.

A notice affixed to an instrument reminding users to keep the instrument level is not a requirement of the new NMI R76-1:2015 (or the earlier edition of NMI R76-1).

However, in cases where the level bubble is not clearly visible to the user, NMI R76 does require a notice indicating the location of the level bubble to the user.

A person who uses a measuring instrument in a way that gives an inaccurate measurement may also be committing an offence under the National Measurement Act (section 18GD).
 
Our recommendation is that you explain to your customers that an instrument that is not level may not be performing an accurate measurement.  Your customers need to make sure their staff knows how to check whether instruments are staying level.

Collapsed - Conversion of weighing instruments greater than 100kg and 6b/0

General Certificate 6B/0 supports the submission of conversion certificates by providing calculations on the suitability of components being used in an instrument conversion or in manufacture. For an instrument with a capacity greater than 100 kg, the submitter of a conversion certificate (e.g. 6B/XXX) can only:
Replace an indicator on a full load cell (other than single load cell instruments) or lever/ load cell NAWI.
  • Convert a mechanical indicating weighing instrument (other than Overhead Track Weighing Instruments) to a lever/load cell instrument.
  • Replace the load cell on a lever load cell weighing instrument to retain the instrument as a lever/load cell instrument.
In all these cases the instrument must be marked with the conversion number (i.e. 6B/XXX).
 
Only the submitter of a full load cell (e.g. 6/10B/XXX) can modify an instrument beyond the above points for a conversion.
 
However, these modifications are limited to what is described in the instrument being modified for approval.
 
For example, where an instrument approval states “The pattern as approved herein or with substitute load cells and/or indicator, and in other capacities, or with different platform sizes, shall comply with General Certificate No 6B/0”, the submitter or a person authorised by the submitter, in this case can make the following modifications:
  • change the indicator
  • change the load cells.
  • change the capacity.
  • change the platform size.
In the example provided, these modifications comply with the 6B/0 calculations. The instrument is considered to have been manufactured by the submitter in accordance with the Certificate of Approval.  As this is not a conversion, no conversion number is required to be marked on the instrument.
 
A submitter of a full load cell weighbridge approval (manufacturer) can change the load cells of another approved full load cell weighbridge submitted by another organisation.
 
However the submitter making the modification (manufacturer) has to assume the metrological responsibility for the instrument and change the approval number to their number, provided their approval permits those modifications and the 6B/0 calculations are acceptable.

Collapsed - What to do when weighbridge platforms are touching each other

Occasionally adjacent platforms on a multi-platform weighbridge can come into contact with each other as vehicles move on and off the weighbridge.  This will usually be due to the way the platforms have been designed or installed.
 
Although the contact may be minimal, the adjacent platform may temporarily display an indication other than zero with no load on that particular platform.  The temporary display of a load other than zero is acceptable while a vehicle is moving over the multi-platform weighbridge.
 

When a vehicle is stationary and the indicators are stable, the indicated weight must reflect the applied load within the applicable MPE (zero or otherwise).

Collapsed - Weighbridges installed without a pit

Weighbridges without a pit are required to comply with National Trade Measurement Regulation 3.7(1) which includes:

  • the clearance under the lowest live part of the platforms must be at least 150 mm.
  • the floor between load cell supports must be:

(i) composed of concrete at least 75 mm thick; and
(ii) effectively drained; and
(iii) kept free from any accumulation of water, mud or debris.

However if a weighbridge does not comply with the requirements of regulation 3.7 the trader should:

  • rectify the weighbridge installation to comply with regulation 3.7; or
  • seek permission in writing with the Manager Licensing and Appointments (tmlicensees@measurement.gov.au) to deviate from the requirements of regulation 3.7 and include:
    • Weighbridge details
      • Location
      • Capacity
      • Serial number
  • Photographs of the installation
  • Details of a risk assessment as to how they will ensure the floor under the weighbridge will be:
    • effectively drained; and
    • kept free from any accumulation of water, mud or debris.