Document ID: chunk:federal_register_of_legislation:F2024L00446:reg:16:p51
Version: federal_register_of_legislation:F2024L00446
Segment Type: reg
Provision Reference: reg 16 (pt 51/108)
Character Range: 1027786–1030959

measured with an accuracy of ±2.5 per cent of reading or ±1.5 per cent full scale, whichever is the least.
              The accuracy specified above of the sample flow from the CVS tunnel is also applicable where double dilution is used. Consequently, the measurement and control of the secondary dilution air flow and diluted exhaust flow rates through the filter shall be of a higher accuracy.
              4.2.1.2.9. All data channels required for the measurement of PM shall be logged at a frequency of 1 Hz or faster. Typically, these would include:
              (a) Diluted exhaust temperature at the particulate sampling filter;
              (b) Sampling flow rate;
                  (c) Secondary dilution air flow rate (if secondary dilution is used);
                  (d) Secondary dilution air temperature (if secondary dilution is used).
              4.2.1.2.10. For double dilution systems, the accuracy of the diluted exhaust transferred from the dilution tunnel Vep defined in paragraph 3.3.2. of Annex B7 in the equation is not measured directly but determined by differential flow measurement.
              The accuracy of the flow meters used for the measurement and control of the double diluted exhaust passing through the particulate sampling filters and for the measurement/control of secondary dilution air shall be sufficient so that the differential volume Vep shall meet the accuracy and proportional sampling requirements specified for single dilution.
              The requirement that no condensation of the exhaust gas occur in the CVS dilution tunnel, diluted exhaust flow rate measurement system, CVS bag collection or analysis systems shall also apply in the case that double dilution systems are used.
              4.2.1.2.11. Each flow meter used in a particulate sampling and double dilution system shall be subjected to a linearity verification as required by the instrument manufacturer.
Figure A5/12
Particulate sampling system
Figure A5/13
Double dilution particulate sampling system
              4.2.1.3. Specific requirements
              4.2.1.3.1. Sample probe
              4.2.1.3.1.1. The sample probe shall deliver the particle size classification performance specified in paragraph 4.2.1.3.1.4. of this annex. It is recommended that this performance be achieved by the use of a sharp-edged, open-ended probe facing directly into the direction of flow plus a pre-classifier (cyclone impactor, etc.). An appropriate sample probe, such as that indicated in Figure A5/11, may alternatively be used provided it achieves the pre-classification performance specified in paragraph 4.2.1.3.1.4. of this annex.
              4.2.1.3.1.2. The sample probe shall be installed at least 10 tunnel diameters downstream of the exhaust gas inlet to the tunnel and have an internal diameter of at least 8 mm.
              If more than one simultaneous sample is drawn from a single sample probe, the flow drawn from that probe shall be split into identical sub-flows to avoid sampling artefacts.
              If multiple probes are used, each probe shall be sharp-edged, open-ended and facing directly into the direction of flow.