Document ID: chunk:federal_register_of_legislation:F2023C00229:reg:9:p24
Version: federal_register_of_legislation:F2023C00229
Segment Type: reg
Provision Reference: reg 9 (pt 24/71)
Character Range: 276199–279474

whole test cycle. For the ESC, considerable attention must be paid to sampling times and flows during the sampling phase of the test.

4.1.                            Particulate sampling filters

4.1.1.                        Filter specification

              Fluorocarbon coated glass fibre filters or fluorocarbon based membrane filters are required. All filter types shall have a 0,3 μm DOP (di-octylphthalate) collection efficiency of at least 95 % at a gas face velocity between 35 and 80 cm/s.

4.1.2.                        Filter size

              Particulate filters must have a minimum diameter of 47 mm (37 mm stain diameter). Larger diameter      filters are acceptable (Section 4.1.5).

4.1.3.                        Primary and back-up filters

              The diluted exhaust shall be sampled by a pair of filters placed in series (one primary and one back-up filter) during the test sequence. The back-up filter shall be located no more than 100 mm downstream of, and shall not be in contact with the primary filter. The filters may be weighed separately or as a pair with the filters placed stain side to stain side.

4.1.4.                        Filter face velocity

              A gas face velocity through the filter of 35 to 80 cm/s shall be achieved. The pressure drop increase between the beginning and the end of the test shall be no more than 25 kPa.

4.1.5.                        Filter loading

              The recommended minimum filter loading shall be 0,5 mg/1 075 mm2 stain area. For the most common filter sizes the values are shown in Table 9.

        Table 9

        Recommended filter loadings

      Filter diameter (mm)        Recommended stain (mm)         Recommended minimum loading (mg)
      47                          37                             0,5
      70                          60                             1,3
      90                          80                             2,3
      110                         100                            3,6

4.2.                            Weighing chamber and analytical balance specifications

4.2.1.                        Weighing chamber conditions

              The temperature of the chamber (or room) in which the particulate filters are conditioned and weighed shall be maintained to within 295 K ± 3 K (22 °C ± 3 °C) during all filter conditioning and weighing. The humidity shall be maintained to a dewpoint of 282,5 K ± 3 K (9,5 °C ± 3 °C) and a relative humidity of 45 % ± 8 %.

4.2.2.                        Reference filter weighing

              The chamber (or room) environment shall be free of any ambient contaminants (such as dust) that would settle on the particulate filters during their stabilisation. Disturbances to weighing room specifications as outlined in Section 4.2.1 will be allowed if the duration of the disturbances does not exceed 30 minutes. The weighing room should meet the required specifications prior to personal entrance into the weighing room. At least two unused reference filters or reference filter pairs shall be weighed within 4 hours of, but preferably at the same time as the sample filter (pair) weighings. They shall be the same size and material as the sample filters.

              If the average weight