Document ID: chunk:federal_register_of_legislation:F2024L00446:reg:16:p54
Version: federal_register_of_legislation:F2024L00446
Segment Type: reg
Provision Reference: reg 16 (pt 54/108)
Character Range: 1036204–1039471

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;
                  (e) During the weighing operation no deviations from the specified conditions are permitted.
              4.2.2.2. Linear response of an analytical balance
              The analytical balance used to determine the filter weight shall meet the linearity verification criteria of Table A5/1 applying a linear regression. This implies a precision of at least ±2 µg and a resolution of at least 1 µg (1 digit = 1 µg). At least 4 equally-spaced reference weights shall be tested. The zero value shall be within ±1 µg.
Table A5/1
Analytical balance verification criteria
Measurement system   Intercept a0  Slope a1     Standard error of estimate ( SEE)  Coefficient of determination r2
Particulate balance  ≤ 1 µg        0.99 – 1.01  ≤ 1 per cent max                   ≥ 0.998

              4.2.2.3. Elimination of static electricity effects
              The effects of static electricity shall be nullified. This may be achieved by grounding the balance through placement upon an antistatic mat and neutralization of the particulate sampling filters prior to weighing using a polonium neutraliser or a device of similar effect. Alternatively, nullification of static effects may be achieved through equalization of the static charge.
              4.2.2.4. Buoyancy correction
              The sample and reference filter weights shall be corrected for their buoyancy in air. The buoyancy correction is a function of sampling filter density, air density and the density of the balance calibration weight, and does not account for the buoyancy of the particulate matter itself.
              If the density of the filter material is not known, the following densities shall be used:
              (a) PTFE coated glass fibre filter: 2,300 kg/m3;
              (b) PTFE membrane filter: 2,144 kg/m3;
                  (c) PTFE membrane filter with polymethylpentene support ring: 920 kg/m3.
              For stainless steel calibration weights, a density of 8,000 kg/m³ shall be used. If the material of the calibration weight is different, its density shall be known and be used. International Recommendation OIML R 111-1 Edition 2004(E) (or equivalent) from International Organization of Legal Metrology on calibration weights should be followed.
              The following equation shall be used:
              where:
                   Pef is the corrected particulate sample mass, mg;
                   Peuncorr is the uncorrected particulate sample mass, mg;
                   ρa is the density of the air, kg/m3;
                   ρw is the density of balance calibration weight, kg/m3;
                   ρf is the density of the particulate sampling filter, kg/m3.
              The density of the air ρa shall be calculated using the following equation:
              pb is the total atmospheric pressure, kPa;
                   Ta is the air temperature in the balance environment, Kelvin (K);
                   Mmix is the molar mass of air in a