SS648:2019 clause 6.4.3

• The meter and its ancillary devices shall be verified and/or calibrated at an interval required by the implementing authority. This interval is subjected to review by the implementing authority.

Challenges:

• Costly and time-consuming process as the meter needs to be removed from site and sent to factory as on site calibration is not possible. It is challenging to verify non-compliance or breach of system integrity and metrological requirement.

• Possess a measurement uncertainty of either:

1. Water Calibration: not more than +/-0.033%
2. Water & Oil Calibration: not more than 0.1% (Master meter is 3 times better than duty meter - a normal duty meter can be certified for commercial use with measurement uncertainty of 0.3% under oil and water calibration).

• Will undergo periodic re-calibration to ensure long term stability.
• Shall be re-calibrated in water annually.
• Shall be solely used for meter verification and not be used for custody transfer operations at any time.

• Master meter will verify the MFM (on bunker tanker) only at a stable verification flow rate (between Qmin and Qmax of the meter) determined from the data on historical operational flow rate of the bunker tanker.
• Minimum 3 consecutive runs at the verification flow rate with repeatability of not more than 0.12%.
• Average accuracy error of the MFM to Master meter shall not be more than +-0.3% to qualify for custody transfer.
• Meter verification report of the MFM will be generated containing the results and relevant critical data upon successful completion of the verification.
• The Implementing Authority will issue the letter of approval to the bunker tanker operator for bunker delivery.
• Vessel calling Singapore for bunkering should ensure the bunker tanker provides the latest verification report and approval letter from the Implementing Authority; Maritime Port Authority of Singapore (MPA) before bunkering commences.