Document ID: chunk:federal_register_of_legislation:F2024L00446:reg:16:p87
Version: federal_register_of_legislation:F2024L00446
Segment Type: reg
Provision Reference: reg 16 (pt 87/108)
Character Range: 1134222–1137313

hour before weighing.
              2.10.1.2.2. The particulate sample filter shall be carefully installed into the filter holder. The filter shall be handled only with forceps or tongs. Rough or abrasive filter handling will result in erroneous weight determination. The filter holder assembly shall be placed in a sample line through which there is no flow.
              2.10.1.2.3. It is recommended that the microbalance be checked at the start of each weighing session, within 24 hours of the sample weighing, by weighing one reference item of approximately 100 mg. This item shall be weighed three times and the arithmetic average result recorded. If the arithmetic average result of the weighings is ±5 μg of the result from the previous weighing session, the weighing session and balance are considered valid.
              2.11. PN sampling
              2.11.1. The steps described in paragraphs 2.11.1.1. to 2.11.1.2. inclusive of this annex shall be taken prior to each test:
              2.11.1.1. The particle specific dilution system and measurement equipment shall be started and made ready for sampling;
              2.11.1.2. The correct function of the PNC and VPR elements of the particle sampling system shall be confirmed according to the procedures listed in paragraphs 2.11.1.2.1. to 2.11.1.2.4. inclusive of this annex.
              2.11.1.2.1. A leak check, using a filter of appropriate performance attached to the inlet of the entire PN measurement system, VPR and PNC, shall report a measured concentration of less than 0.5 particles per cm³.
              2.11.1.2.2. Each day, a zero check on the PNC, using a filter of appropriate performance at the PNC inlet, shall report a concentration of ≤ 0.2 particles per cm³. Upon removal of the filter, the PNC shall show an increase in measured concentration and a return to ≤ 0.2 particles per cm³ on replacement of the filter. The PNC shall not report any error.
              2.11.1.2.3. It shall be confirmed that the measurement system indicates that the evaporation tube, where featured in the system, has reached its correct operating temperature.
              2.11.1.2.4. It shall be confirmed that the measurement system indicates that the diluter PND1 has reached its correct operating temperature.
              2.12. Sampling during the test
              2.12.1. The dilution system, sample pumps and data collection system shall be started.
              2.12.2. The PM and PN sampling systems shall be started.
              2.12.3. Particle number shall be measured continuously. The arithmetic average concentration shall be determined by integrating the analyser signals over each phase.
              2.12.4. Sampling shall begin before or at the initiation of the powertrain start procedure and end on conclusion of the cycle.
              2.12.5. Sample switching
              2.12.5.1. Gaseous emissions
              Sampling from the diluted exhaust and dilution air shall be switched from one pair of sample bags to subsequent bag pairs, if necessary, at the end of each phase of the