5.9.3 Sampling for gaseous emissions
Clasification Society 2024 - Version 9.40
Statutory Documents - IMO Publications and Documents - International Codes - NOx Technical Code (2008) - Technical Code on Control of Emission of Nitrogen Oxides from Marine Diesel Engines - Chapter 5 - Procedures for NOx emission measurements on a test bed - 5.9 Test run - 5.9.3 Sampling for gaseous emissions

5.9.3 Sampling for gaseous emissions

  5.9.3.1 The sampling probes for the gaseous emissions shall be fitted at least 10 pipe diameters after the outlet of the engine, turbocharger, or last after-treatment device, whichever is furthest downstream, but also at least 0.5 m or 3 pipe diameters upstream of the exit of the exhaust gas system, whichever is greater. For a short exhaust system that does not have a location that meets both of these specifications, an alternative sample probe location shall be subject to approval by the Administration.

  5.9.3.2 The exhaust gas temperature shall be at least 190°C at the HC sample probe, and at least 70°C at the sample probes for other measured gas species where they are separate from the HC sample probe.

  5.9.3.3 In the case of a multi-cylinder engine with a branched exhaust manifold, the inlet of the probe shall be located sufficiently far downstream so as to ensure that the sample is representative of the average exhaust emissions from all cylinders. In the case of a multi-cylinder engine having distinct groups of manifolds, it is permissible to acquire a sample from each group individually and calculate an average exhaust emission. Alternatively, it would also be permissible to acquire a sample from a single group to represent the average exhaust emission provided that it can be justified to the Administration that the emissions from other groups are identical. Other methods, subject to the approval of the Administration, that have been shown to correlate with the above methods may be used. For exhaust emission calculation, the total exhaust mass flow shall be used.

  5.9.3.4 The exhaust gas sampling system shall be leakage tested in accordance with section 4 of appendix 4 of this Code.

  5.9.3.5 If the composition of the exhaust gas is influenced by any exhaust after-treatment system, the exhaust gas sample shall be taken downstream of that device.

  5.9.3.6 The inlet of the probe shall be located as to avoid ingestion of water that is injected into the exhaust system for the purpose of cooling, tuning or noise reduction.

Parent topic: 5.9 Test run
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