Document ID: chunk:federal_register_of_legislation:F2023C00229:reg:110:p8
Version: federal_register_of_legislation:F2023C00229
Segment Type: reg
Provision Reference: reg 110 (pt 8/59)
Character Range: 623739–626533

to sections 2.1 to 2.3 of Appendix 6 to this Annex. All carbon flow rates should agree to within 6 % of each other.

        3.2.3. Pre-test check

                -          A pre-test check shall be performed within 2 hours before the test run in the following way:

                -          The accuracy of the flow meters shall be checked by the same method as used for calibration (see section 3.2.1) for at least two points, including flow values of qmdw that correspond to dilution ratios between 5 and 15 for the qmdew value used during the test.

                -          If it can be demonstrated by records of the calibration procedure under section 3.2.1 that the flow meter calibration is stable over a longer period of time, the pre-test check may be omitted.

        3.3.  Determination of transformation time (for partial flow dilution systems on ETC only)

                -          The system settings for the transformation time evaluation shall be exactly the same as during measurement of the test run. The transformation time shall be determined by the following method:

                -          An independent reference flowmeter with a measurement range appropriate for the probe flow shall be put in series with and closely coupled to the probe. This flowmeter shall have a transformation time of less than 100 ms for the flow step size used in the response time measurement, with flow restriction sufficiently low as to not affect the dynamic performance of the partial flow dilution system, and consistent with good engineering practice.

                -          A step change shall be introduced to the exhaust flow (or air flow if exhaust flow is calculated) input of the partial flow dilu- tion system, from a low flow to at least 90 % of full scale. The trigger for the step change should be the same one used to start the look-ahead control in actual testing. The exhaust flow step stimulus and the flowmeter response shall be recorded at a sample rate of at least 10 Hz.

                -          From this data, the transformation time shall be determined for the partial flow dilution system, which is the time from the initiation of the step stimulus to the 50 % point of the flowmeter response. In a similar manner, the transformation times of the qmp signal of the partial flow dilution system and of the qmew,I signal of the exhaust flow meter shall be determined. These signals are used in the regression checks performed after each test (see section 3.8.3.2 of Appendix 2 to this Annex).

                -          The calculation shall be repeated for at least 5 rise and fall stimuli, and the results shall be averaged. The internal transforma- tion time (< 100 msec) of the reference flowmeter shall be subtracted from this value. This