Document ID: chunk:federal_register_of_legislation:F2024L00446:reg:16:p53
Version: federal_register_of_legislation:F2024L00446
Segment Type: reg
Provision Reference: reg 16 (pt 53/108)
Character Range: 1033403–1036488

temperature of the gas flow in the flow meter may not fluctuate by more than ±3 °C except:
                  (a) When the sampling flow meter has real time monitoring and flow control operating at a frequency of 1 Hz or faster;
                  (b) During regeneration tests on vehicles equipped with periodically regenerating after-treatment devices.
              Should the volume of flow change unacceptably as a result of excessive filter loading, the test shall be invalidated. When it is repeated, the flow rate shall be decreased.
              4.2.1.3.5. Filter and filter holder
              4.2.1.3.5.1. A valve shall be located downstream of the filter in the direction of flow. The valve shall open and close within 1 second of the start and end of test.
              4.2.1.3.5.2. For a given test, the gas filter face velocity shall be set to an initial value within the range 20 cm/s to 105 cm/s and shall be set at the start of the test so that 105 cm/s will not be exceeded when the dilution system is being operated with sampling flow proportional to CVS flow rate.
              4.2.1.3.5.3. Fluorocarbon coated glass fibre filters or fluorocarbon membrane filters shall be used.
              All filter types shall have a 0.3 μm DOP (di-octylphthalate) or PAO (poly-alpha-olefin) CS 68649-12-7 or CS 68037-01-4 collection efficiency of at least 99 per cent at a gas filter face velocity of 5.33 cm/s measured according to one of the following standards:
                  (a) U.S.A. Department of Defense Test Method Standard, MIL-STD-282 method 102.8: DOP-Smoke Penetration of Aerosol-Filter Element;
                  (b) U.S.A. Department of Defense Test Method Standard, MIL-STD-282 method 502.1.1: DOP-Smoke Penetration of Gas-Mask Canisters;
                  (c) Institute of Environmental Sciences and Technology, IEST-RP-CC021: Testing HEPA and ULPA Filter Media.
              4.2.1.3.5.4. The filter holder assembly shall be of a design that provides an even flow distribution across the filter stain area. The filter shall be round and have a stain area of at least 1,075 mm2.
              4.2.2. Weighing chamber (or room) and analytical balance specifications
              4.2.2.1. Weighing chamber (or room) conditions
                  (a) The temperature of the weighing chamber (or room) in which the particulate sampling filters are conditioned and weighed shall be maintained to within 22 °C ±2 °C (22 °C ±1 °C if possible) during all filter conditioning and weighing;
                  (b) Humidity shall be maintained at a dew point of less than 10.5 °C and a relative humidity of 45 per cent ±8 per cent;
                  (c) Limited deviations from weighing chamber (or room) temperature and humidity specifications shall be permitted provided their total duration does not exceed 30 minutes in any one filter conditioning period;
                  (d) The levels of ambient contaminants in the weighing chamber (or room) environment that would settle on the particulate sampling filters during their stabilisation shall be minimised;