Document ID: chunk:federal_register_of_legislation:F2024L00446:reg:16:p58
Version: federal_register_of_legislation:F2024L00446
Segment Type: reg
Provision Reference: reg 16 (pt 58/108)
Character Range: 1047811–1052564

a t90 response time over the measured concentration range of less than 5 seconds;
                  (g) Introduce a correction with a calibration factor as determined in paragraph 5.7.1.3. of this annex;
                  (h) Have counting efficiencies at the different particle sizes as specified in Table A5/2.

                  (i) The PNC calibration factor from the linearity calibration against a traceable reference shall be applied to determine PNC counting efficiency. The counting efficiency shall be reported including the calibration factor from linearity calibration against a traceable reference.

                  (j) If the PNC applies some other working liquid besides n-butyl alcohol or isopropyl alcohol, the counting efficiency of the PNC shall be demonstrated with 4cSt polyalphaolefin and soot-like particles.
Table A5/2
    PNC counting efficiency

Nominal particle electrical mobility diameter (nm)  PNC counting efficiency (per cent)
 23                                                  50 ±12
 41                                                  > 90

              4.3.1.3.5. If the PNC makes use of a working liquid, it shall be replaced at the frequency specified by the instrument manufacturer.
              4.3.1.3.6. Where not held at a known constant level at the point at which PNC flow rate is controlled, the pressure and/or temperature at the PNC inlet shall be measured for the purposes of correcting particle number concentration measurements to standard conditions. The standard conditions are 101.325 kPa pressure and 0 °C temperature.
              4.3.1.3.7. The sum of the residence time of the PTS, VPR and OT plus the t90 response time of the PNC shall be no greater than 20 seconds.
              4.3.1.4. Recommended system description
              The following paragraph contains the recommended practice for measurement of PN. However, systems meeting the performance specifications in paragraphs 4.3.1.2. and 4.3.1.3. of this annex are acceptable. See Figure A5/14.
Figure A5/14
A recommended particle sampling system
The evaporation tube, ET, may be catalytically active with a wall temperature of 350 °C (±10 °C).
              5. Calibration intervals and procedures
              5.1. Calibration intervals
              All instruments in Table A5/3 shall be calibrated at/after major maintenance intervals.
Table A5/3
Instrument calibration intervals
Instrument checks                                                                                            Interval                               Criterion
Gas analyser linearization (calibration)                                                                     Every 6 months                         ±2 per cent of reading
Mid-span                                                                                                     Every 6 months                         ±2 per cent
CO NDIR:                                                                                                     Monthly                                -1 to 3 ppm
CO2/H2O interference
NOx converter check                                                                                          Monthly                                > 95 per cent
CH4 cutter check                                                                                             Yearly                                 98 per cent of ethane
FID CH4 response                                                                                             Yearly                                 See paragraph 5.4.3. of this annex.
FID air/fuel flow                                                                                            At major maintenance                   According to the instrument manufacturer.
NO/NO2 NDUV:                                                                                                 At major maintenance                   According to the instrument manufacturer.
H2O, HC interference
Laser infrared spectrometers (modulated high resolution narrow band infrared analysers): interference check  Yearly                                 According to the instrument manufacturer.
QCL                                                                                                          Yearly                                 According to the instrument manufacturer.
GC methods                                                                                                   See paragraph 7.2. of this annex.      See paragraph 7.2. of this annex.
LC methods                                                                                                   Yearly                                 According to the instrument manufacturer.