1.3 Accuracy of measuring instruments
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1.3 Accuracy of measuring instruments

  1.3.1 The calibration of all measuring instruments shall comply with the requirements as set out in tables 1, 2, 3 and 4 and shall be traceable to standards recognized by the Administration. Additional engine measurements may be required by the Administration, and such additional measuring instruments used shall comply with the appropriate deviation standard and calibration validity period.

  1.3.2 The instruments shall be calibrated:

  • .1 in time intervals not greater than as given in tables 1, 2, 3 and 4; or

  • .2 in accordance with alternative calibration procedures and validity periods subject to such proposals being submitted in advance of the tests and approved by the Administration.

  Note: The deviations given in tables 1, 2, 3, and 4 refer to the final recorded value, which is inclusive of the data acquisition system.

Table 1 Permissible deviations and calibration validity periods of instruments for engine-related parameters for measurements on a test bed

No. Measurement instrument Permissible deviation Calibration validity period (months)
1 Engine speed ± 2% of reading or ± 1% of engine’s maximum value, whichever is larger 3
2 Torque ± 2% of reading or ± 1% of engine’s maximum value, whichever is larger 3
3 Power (where measured directly) ± 2% of reading or ± 1% of engine’s maximum value, whichever is larger 3
4 Fuel consumption ± 2% of engine’s maximum value 6
5 Air consumption ± 2% of reading or ± 1% of engine’s maximum value, whichever is larger 6
6 Exhaust gas flow ± 2.5% of reading or ± 1.5% of engine’s maximum value, whichever is larger 6

Table 2 Permissible deviations and calibration intervals periods of instruments for other essential parameters for measurements on a test bed

No. Measurement instrument Permissible deviation Calibration validity period (months)
1 Temperatures ≤ 327oC ± 2oC absolute 3
2 Temperatures > 327oC ± 1% of reading 3
3 Exhaust gas pressure ± 0.2 kPa absolute 3
4 Charge air pressure ± 0.3 kPa absolute 3
5 Atmospheric pressure ± 0.1 kPa absolute 3
6 Other pressures ≤ 1000 kPa ± 20 kPa absolute 3
7 Other pressures > 1000 kPa ± 2% of reading 3
8 Relative humidity ± 3% absolute 1

Table 3 Permissible deviations and calibration validity periods of instruments for engine-related parameters for measurements on board a ship when the engine is already pre-certified

No. Measurement instrument Permissible deviation Calibration validity period (months)
1 Engine speed ± 2% of engine’s maximum value 12
2 Torque ± 5% of engine’s maximum value 12
3 Power (where measured directly) ± 5% of engine’s maximum value 12
4 Fuel consumption ± 4% of engine’s maximum value 12
5 Air consumption ± 5% of engine’s maximum value 12
6 Exhaust gas flow ± 5% of engine’s maximum value 12

Table 4 Permissible deviations calibration validity period of instruments for other essential parameters for measurements on board a ship when the engine is already pre-certified

No. Measurement instrument Permissible deviation Calibration validity period (months)
1 Temperatures ≤ 327oC ± 2oC absolute 12
2 Temperatures > 327oC ± 15oC absolute 12
3 Exhaust gas pressure ± 5% of engine’s maximum value 12
4 Charge air pressure ± 5% of engine’s maximum value 12
5 Atmospheric pressure ± 0.5% of reading 12
6 Other pressures ± 5 % of reading 12
7 Relative humidity ± 3% absolute 6
Parent topic: 1 Introduction
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