Document ID: chunk:federal_register_of_legislation:F2024L00446:reg:16:p61
Version: federal_register_of_legislation:F2024L00446
Segment Type: reg
Provision Reference: reg 16 (pt 61/108)
Character Range: 1058666–1061679

shall be tested by means of an ozonator as follows:
              5.5.1.1. The analyser shall be calibrated in the most common operating range following the manufacturer's specifications using zero and calibration gas (the NO content of which shall amount to approximately 80 per cent of the operating range and the NO2 concentration of the gas mixture shall be less than 5 per cent of the NO concentration). The NOx analyser shall be in the NO mode so that the calibration gas does not pass through the converter. The indicated concentration shall be recorded.
              5.5.1.2. Via a T-fitting, oxygen or synthetic air shall be added continuously to the calibration gas flow until the concentration indicated is approximately 10 per cent less than the indicated calibration concentration given in paragraph 5.5.1.1. of this annex. The indicated concentration (c) shall be recorded. The ozonator shall be kept deactivated throughout this process.
              5.5.1.3. The ozonator shall now be activated to generate enough ozone to bring the NO concentration down to 20 per cent (minimum 10 per cent) of the calibration concentration given in paragraph 5.5.1.1. of this annex. The indicated concentration (d) shall be recorded.
              5.5.1.4. The NOx analyser shall be subsequently switched to the NOx mode, whereby the gas mixture (consisting of NO, NO2, O2 and N2) now passes through the converter. The indicated concentration (a) shall be recorded.
              5.5.1.5. The ozonator shall now be deactivated. The mixture of gases described in paragraph 5.5.1.2. of this annex shall pass through the converter into the detector. The indicated concentration (b) shall be recorded.
Figure A5/15
NOx converter efficiency test configuration
              5.5.1.6. With the ozonator deactivated, the flow of oxygen or synthetic air shall be shut off. The NO2 reading of the analyser shall then be no more than 5 per cent above the figure given in paragraph 5.5.1.1. of this annex.
              5.5.1.7. The per cent efficiency of the NOx converter shall be calculated using the concentrations a, b, c and d determined in paragraphs 5.5.1.2. to 5.5.1.5. inclusive of this annex using the following equation:
              The efficiency of the converter shall not be less than 95 per cent. The efficiency of the converter shall be tested in the frequency defined in Table A5/3.
              5.6. Calibration of the microgram balance
              The calibration of the microgram balance used for particulate sampling filter weighing shall be traceable to a national or international standard. The balance shall comply with the linearity requirements given in paragraph 4.2.2.2. of this annex. The linearity verification shall be performed at least every 12 months or whenever a system repair or change is made that could influence the calibration.
              5.7. Calibration and validation of the particle sampling system
              Examples of calibration/validation methods are available