Document ID: chunk:federal_register_of_legislation:F2024C00356:reg:21:p31
Version: federal_register_of_legislation:F2024C00356
Segment Type: reg
Provision Reference: reg 21 (pt 31/35)
Character Range: 373094–376301

alarms a 12 month validation interval shall be permissible.
               The VPR shall be characterised for particle concentration reduction factor with solid particles of 30 nm, 50 nm and 100 nm electrical mobility diameter. Particle concentration reduction factors (fr(d)) for particles of 30 nm and 50 nm electrical mobility diameters shall be no more than 30 per cent and 20 per cent higher respectively, and no more than 5 per cent lower than that for particles of 100 nm electrical mobility diameter. For the purposes of validation, the mean particle concentration reduction factor shall be within ±10 per cent of the mean particle concentration reduction factor () determined during the primary calibration of the VPR.
              2.2.2. The test aerosol for these measurements shall be solid particles of 30, 50 and 100 nm electrical mobility diameter and a minimum concentration of 5,000 particles cm-3 at the VPR inlet. Particle concentrations shall be measured upstream and downstream of the components.
               The particle concentration reduction factor at each particle size (fr(di)) shall be calculated as follows;

 Where:
 Nin(di)                                                          =  upstream particle number concentration for particles of diameter di;
 Nout(di)                                                         =  downstream particle number concentration for particles of diameter di; and
 di                                                               =  particle electrical mobility diameter (30, 50 or 100 nm).
 Nin(di) and Nout(di) shall be corrected to the same conditions.

               The mean particle concentration reduction () at a given dilution setting shall be calculated as follows;

               It is recommended that the VPR is calibrated and validated as a complete unit.
              2.2.3. The Technical Service shall ensure the existence of a validation certificate for the VPR demonstrating effective volatile particle removal efficiency within a 6 month period prior to the emissions test. If the volatile particle remover incorporates temperature monitoring alarms a 12 month validation interval shall be permissible. The VPR shall demonstrate greater than 99.0 per cent removal of tetracontane (CH3(CH2)38CH3) particles of at least 30 nm electrical mobility diameter with an inlet concentration of ≥ 10,000 cm-3 when operated at its minimum dilution setting and manufacturers recommended operating temperature.

              2.3. Particle Number System Check Procedures
              2.3.1. Prior to each test, the particle counter shall report a measured concentration of less than 0.5 particles cm-3 when a HEPA filter of at least class H13 of EN 1822:2008, or equivalent performance, is attached to the inlet of the entire particle sampling system (VPR and PNC).
              2.3.2. On a monthly basis, the flow into the particle counter shall report a measured value within 5 per cent of the particle counter nominal flow rate when checked with a calibrated flow meter.
              2.3.3. Each day, following the application of a HEPA filter of at least class H13 of EN 1822:2008, or equivalent performance, to the inlet of