Document ID: chunk:federal_register_of_legislation:F2023C00229:reg:110:p5
Version: federal_register_of_legislation:F2023C00229
Segment Type: reg
Provision Reference: reg 110 (pt 5/59)
Character Range: 615751–618813

HC analysers shall be set at zero

                -          The appropriate calibration gases shall be introduced to the analysers, the values recorded, and the calibration curve established

                -          The calibration curve shall be established by at least 6 calibration points (excluding zero) approximately equally spaced over the operating range. The highest nominal concentration shall be equal to or higher than 90 % of full scale

                -          The calibration curve shall be calculated by the method of least-squares. A best-fit linear or non-linear equation may be used

                -          The calibration points shall not differ from the least-squares best-fit line by more than ± 2 % of reading or ± 0,3 % of full scale whichever is larger

                -          The zero setting shall be rechecked and the calibration procedure repeated, if necessary.

        1.6.5. Alternative methods

              If it can be shown that alternative technology (e.g. computer, electronically controlled range switch, etc.) can give equivalent accu- racy, then these alternatives may be used.

        1.6.6. Calibration of tracer gas analyser for exhaust flow measurement

              The calibration curve shall be established by at least 6 calibration points (excluding zero) approximately equally spaced over the operating range. The highest nominal concentration shall be equal to or higher than 90 % of full scale. The calibration curve is cal- culated by the method of least squares.

              The calibration points shall not differ from the least-squares best-fit line by more than ± 2 % of reading or ± 0,3 % of full scale whichever is larger.

              The analyser shall be set at zero and spanned prior to the test run using a zero gas and a span gas whose nominal value is more than 80 % of the analyser full scale.'

         (v)     Former section 1.6 becomes section 1.6.7.
         (vi)
         (vii)  The following section 2.4 is inserted:

        '2.4. Calibration of the Subsonic Venturi (SSV)

              Calibration of the SSV is based upon the flow equation for a subsonic venturi. Gas flow is a function of inlet pressure and tem- perature, pressure drop between the SSV inlet and throat.

              2.4.1. Data analysis

              The air flowrate (QSSV) at each restriction setting (minimum 16 settings) shall be calculated in standard m3/min from the flowmeter data using the manufacturer's prescribed method. The discharge coefficient shall be calculated from the calibration data for each setting as follows:
              where:

              QSSV = air flow rate at standard conditions (101,3 kPa, 273 K), m3/s
              T = temperature at the venturi inlet, K
              d = diameter of the SSV throat, m
              rp = ratio of the SSV throat to inlet absolute, static pressure =

              rD = ratio of the SSV throat diameter, d, to the inlet pipe inner diameter =

              To determine the range of subsonic flow, Cd shall be plotted