6.3.1 General
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Statutory Documents - IMO Publications and Documents - International Codes - NOx Technical Code - Technical Code on Control of Emission of Nitrous Oxides from Marine Diesel Engines - Chapter 6 - Procedures for demonstrating compliance with NOx emission limits on board - 6.3 Simplified measurement method - 6.3.1 General

6.3.1 General

  6.3.1.1 The following simplified test and measurement procedure specified in this section shall be applied only for on-board confirmation tests and periodical and intermediate surveys when required. Every first engine testing on a test bed shall be carried out in accordance with the procedure specified in chapter 5 using a DM-grade marine diesel fuel. Corrections for ambient air temperature and humidity in accordance with 5.12.3 are essential as ships are sailing in cold/hot and dry/humid climates, which may cause a difference in NOx emissions.

  6.3.1.2 To gain meaningful results for on-board confirmation tests and on-board periodical and intermediate surveys, as an absolute minimum, the gaseous emission concentrations of NOx, together with O2 and/or CO2 and CO, shall be measured in accordance with the appropriate test cycle. The weighting factors (W F) and the number of modes (n) used in the calculation shall be in accordance with 3.2.

  6.3.1.3 The engine torque and engine speed shall be measured but, to simplify the procedure, the permissible deviations of instruments (see 6.3.7) for measurement of engine-related parameters for on-board verification purposes is different than from those permissible deviations allowed under the test-bed testing method. If it is difficult to measure the torque directly, the brake power may be estimated by any other means recommended by the engine manufacturer and approved by the Administration.

  6.3.1.4 In practical cases, it is often impossible to measure the fuel consumption once an engine has been installed on board a ship. To simplify the procedure on board, the results of the measurement of the fuel consumption from an engine's pre-certification test-bed testing may be accepted. In such cases, especially concerning heavy fuel operation, an estimation with a corresponding estimated error shall be made. Since the oil fuel flow rate used in the calculation (G FUEL) must relate to the oil fuel composition determined in respect of the fuel sample drawn during the test, the measurement of G FUEL from the test-bed testing shall be corrected for any difference in net calorific values between the test-bed and test oil fuels. The consequences of such an error on the final emissions shall be calculated and reported with the results of the emission measurement.

  6.3.1.5 Except as otherwise specified, all results of measurements, test data or calculations required by this chapter shall be recorded in the engine's test report in accordance with 5.10.

Parent topic: 6.3 Simplified measurement method
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