Document ID: chunk:federal_register_of_legislation:F2023L00129:reg:13:p10
Version: federal_register_of_legislation:F2023L00129
Segment Type: reg
Provision Reference: reg 13 (pt 10/27)
Character Range: 576490–579599

PNC and the gas temperature prior to entry to the PNC is < 35 °C.
              A.8.1.4.5. Particle number counter (PNC)
               The PNC shall meet the requirements of paragraph A.8.1.3.4.
              A.8.2. Calibration/Validation of the particle sampling system[28]
              A.8.2.1. Calibration of the particle number counter
              A.8.2.1.1. The Technical Service shall ensure the existence of a calibration certificate for the PNC demonstrating compliance with a traceable standard within a
              12-month period prior to the emissions test.
              A.8.2.1.2. The PNC shall also be recalibrated and a new calibration certificate issued following any major maintenance.
              A.8.2.1.3. Calibration shall be traceable to a standard calibration method:
                   (a) By comparison of the response of the PNC under calibration with that of a calibrated aerosol electrometer when simultaneously sampling electrostatically classified calibration particles; or
                   (b) By comparison of the response of the PNC under calibration with that of a second PNC which has been directly calibrated by the above method.
               In the electrometer case, calibration shall be undertaken using at least six standard concentrations spaced as uniformly as possible across the PNC's measurement range. These points will include a nominal zero concentration point produced by attaching HEPA filters of at least class H13 of EN 1822:2008, or equivalent performance, to the inlet of each instrument. With no calibration factor applied to the PNC under calibration, measured concentrations shall be within ±10 per cent of the standard concentration for each concentration used, with the exception of the zero point, otherwise the PNC under calibration shall be rejected. The gradient from a linear regression of the two data sets shall be calculated and recorded. A calibration factor equal to the reciprocal of the gradient shall be applied to the PNC under calibration. Linearity of response is calculated as the square of the Pearson product moment correlation coefficient (R2) of the two data sets and shall be equal to or greater than 0.97. In calculating both the gradient and R2 the linear regression shall be forced through the origin (zero concentration on both instruments).
               In the reference PNC case, calibration shall be undertaken using at least six standard concentrations across the PNC's measurement range. At least 3 points shall be at concentrations below 1,000 cm-3, the remaining concentrations shall be linearly spaced between 1,000 cm-3 and the maximum of the PNC's range in single particle count mode. These points will include a nominal zero concentration point produced by attaching HEPA filters of at least class H13 of EN 1822:2008, or equivalent performance, to the inlet of each instrument. With no calibration factor applied to the PNC under calibration, measured concentrations shall be within ±10 per cent of the standard concentration for each concentration, with the exception of the zero point, otherwise