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Verifying fuel dispensers for trade

A servicing licensee tests and verifies fuel dispensers used for trade. 

For a fuel dispenser to be suitable for trade use, it must:

  • operate within the limits of error permitted under the regulations
  • be pattern approved

Test procedures

You test fuel dispensers using these National Instrument Test Procedures (NITPs):

Certificates of approval

We issue certificates of approval for pattern approved fuel dispensers under these categories:

Flow measurement 

You calibrate most liquid flowmeters by passing a known volume of test fluid through a prover. You determine the prover volume using water in place of the test fluid and measuring its weight. 

Calibrating gas flowmeters is more complex than other liquid flowmeters because of the low density and compressibility of gases. 

To establish standards for gas flow use a bell prover to pass a known volume of gas through a sonic nozzle, at a known:

  • temperature
  • pressure 
  • flow rate

The velocity of the gas flow in the sonic nozzle is equal to the velocity of sound. Under these conditions the flow rate depends only on the upstream temperature and pressure of the gas. You use the calibrated sonic nozzle as a working standard to calibrate other gas flow instruments.

Re-verifying after adjustment or repair

You may need to verify a fuel dispenser after it has been adjusted or repaired. This depends on whether the non-compliance issue could affect its metrological performance.

When not to re-verify

Don’t re-verify if a trade measurement inspector has marked it non-compliant because of:

  • 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 anti-drain valve
  • faulty delivery hose
  • faulty motor or pump
  • faulty nozzle
  • faulty individual segments in a display (electromagnetic type)
  • instrument used on non-approved liquid
  • leaks in pipe work upstream of meter

After repair, the trader can use the instrument for trade. 

When to re-verify

You will need to re-verify if the non-compliance issues include:

  • faults in electronic circuit boards
  • faulty LCD displays (unreadable)
  • incorrect software version in use
  • price computing errors
  • accuracy and/or air elimination in excess of the maximum permission errors
  • accuracy of preset incorrect
  • faulty interlock
  • faulty low-level device
  • faulty non-return valve
  • faulty conversion device
  • leaks in pipe work downstream of meter
  • meter creep
  • outside flow rate range

Ensure you remove or obliterate the previous verification mark. After any adjustment or repair, you can re-verify the instrument.

Fuel dispenser serial numbers

There is no industry standard for numbering fuel dispenser hoses. However, manufacturers do have to identify individual fuel dispensers and mark them as per their pattern approval requirements.

The Fuel Dispenser Numbering Guide [5MB PDF] outlines each manufacturers’ numbering system. This helps verifiers and inspectors identify and record the correct serial numbers. We can then use this data to identify instrument performance trends and plan inspection activities.

High-flow fuel compliance

We inspect high-flow fuel installations using our bulk flowmeter truck. We assess the level of compliance for bulk fuel sales in local and accessible remote locations. 

We generally find that flowmeters measure high-flow fuel correctly. 

We come across non-compliance issues such as:

  • not having leak detectors fitted on submersible pumps
  • control systems that are either:
    • not approved
    • not marked with a Pattern Approval number
    • not verified

Please review your training and procedures to make sure equipment including control systems are being identified appropriately.

Flowmeter safety features

Some bulk flowmetering systems have safety features and devices installed downstream of the meter or transfer point to comply with safety design standards or procedures. The International Organization of Legal Metrology (OIML) recommendations or the certificate of approval may not include these safety features.

These safety features may include:

  • sample collection devices 
  • pressure or thermal relief valves
  • debris filters

The sample collection device can impact the instrument’s metrological performance. It must be installed so that a sample can’t be taken at the same time as the delivery of fuel to a purchaser. 

Bulk flowmetering systems for liquid hydrocarbons can have safety features installed that can divert measured liquid downstream of the meter. Any diversion of flow to another outlet must be apparent. This can be a physical barrier, visible valves or other indications as to which outlets are in operation.

For pressure or thermal relief valves, the opening pressure must exceed the maximum approved operating pressure for the flowmetering system.

Test all bulk flowmetering systems according to its relevant NITP within the approved operating conditions. This ensures the system complies with all relevant criteria, including maximum permissible errors. 

Email tmlicensees@measurement.gov.au if non-NMI design requirements may have implications for the certificate of approval or test procedure.

Calibration services

If using flowmeters to meter the flow of LPG, diesel and petrol, they must be accurately calibrated. This ensures that fair and reliable transactions can take place at all levels of the distribution chain.

Our Londonderry facility, in Western Sydney, provides testing and calibration services for LPG, diesel and petrol flowmeters.

Diesel exhaust fluid (e.g. AdBlue) dispensers

New diesel powered vehicles have a selective catalytic reduction (SCR) process to reduce the level of harmful nitrogen oxides emissions.

You may need to verify the dispenser or bulk flow metre used to supply the diesel exhaust fluid (DEF) used in the SCR process. DEF is widely available across Australia and is typically marketed as AdBlue, a solution of 32.5% aqueous urea and 67.5% demineralised water.

How does the SCR work?

A catalytic converter in the vehicle exhaust system mixes DEF with exhaust gases to convert the nitrogen oxides in the exhaust into nitrogen and water.

A gaseous reductant such as anhydrous ammonia, aqueous ammonia or urea is added to a stream of exhaust gas and is absorbed onto the catalytic converter. Carbon dioxide is a reaction product when urea is used as the reductant.

The aqueous urea vaporizes and forms ammonia and carbon dioxide. The nitrogen oxides are catalytically reduced by the ammonia (NH3) into water (H2O) and nitrogen (N2), and released through the exhaust.

DEF dispensers

Flowmeters used to dispense DEF are pattern approved under categories:

  • 5/6A fuel dispensers
  • 5/6B bulk flowmeters

Some approved patterns include the use of a coriolis type meter (mass flowmeter). Components are generally stainless steel to prevent corrosion.

DEF is generally stored in an above ground tank. The storage tank is filled via a camlock fitting inside the container. As you can’t return the product to the storage tank, the site controller should provide a suitable vessel (i.e. clean and empty plastic 200 L drum) to use during testing.

Generally, the dispenser nozzles are fitted with a magnetically operated valve in the spout to prevent accidental cross contamination with diesel fuel. When filling a vehicle, the magnetically operated valve is opened once the nozzle passes through a magnetised fitting when inserted into the vehicle’s DEF tank. When testing, use a DEF adaptor to deliver product into a suitable volume measure (i.e. a 15 L stainless steel conical volume measure).

Testing DEF dispensers

Use the appropriate NITPs:

These instruments do not have a gas elimination system. They rely on a low-level device in the supply tank to prevent air entering the system. NITP 5.1 does not detail how to perform a low level cut-off test. If you need to assess whether the low-level device is working correctly, apply the test detailed in section 4.11 of NITP 5.2.

Licence class

A licensee only needs subclass 5.1 or 5.2 on their licence to verify diesel exhaust fluid measuring instruments, depending on whether it is a dispenser or flowmeter.

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Last updated: 8 December 2020

Content ID: 64632