Document ID: chunk:federal_register_of_legislation:F2011C00805:reg:120:p18
Version: federal_register_of_legislation:F2011C00805
Segment Type: reg
Provision Reference: reg 120 (pt 18/23)
Character Range: 283386–286208

the requirements of paragraph 4.7. of Annex 4, the total accuracy of the CVS sampling system and analytical system shall be determined by introducing a known mass of a pollutant gas into the system whilst it is being operated as if during a normal test and then analysing and calculating the pollutant mass according to the formulae in Appendix 8 to Annex 4 except that the density of propane shall be taken as 1.967 grams per litre at standard conditions. The following two techniques are known to give sufficient accuracy.

         2. Metering a constant flow of pure gas (CO or C3H8) using a critical flow orifice device

         2.1. A known quantity of pure gas (CO OR C3H8) is fed into the CVS system through the calibrated critical orifice. If the inlet pressure is high enough, the flow-rate (q), which is adjusted by means of the critical flow orifice, is independent of orifice outlet pressure (critical flow). If deviations exceeding 5 per cent occur, the cause of the malfunction shall be determined and corrected. The CVS system is operated as in an exhaust emission test for about 5 to 10 minutes. The gas collected in the sampling bag is analysed by the usual equipment and the results compared to the concentration of the gas samples which was known beforehand.

         3.  Metering a limited quantity of pure gas (CO or C3H8) by means of a gravimetric technique

         3.1. The following gravimetric procedure may be used to verify the CVS system.

         The weight of a small cylinder filled with either carbon monoxide or propane is determined with a precision of  0.01 g. For about 5 to 10 minutes, the CVS system is operated as in a normal exhaust emission test, while CO or propane is injected into the system. The quantity of pure gas involved is determined by means of differential weighing. The gas accumulated in the bag is then analysed by means of the equipment normally used for exhaust-gas analysis. The results are then compared to the concentration figures computed previously.

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Annex 4 - Appendix 8

CALCULATION OF THE MASS EMISSIONS OF POLLUTANTS

         1. GENERAL PROVISIONS

         1.1. Mass emissions of gaseous pollutants shall be calculated by means of the following equation:
                                            (1)
         where:

                   Mi = mass emission of the pollutant i in grams per kilometre,

                   Vmix = volume of the diluted exhaust gas expressed in litres per test and corrected to standard conditions (273.2 K and 101.33 kPa),

                   Qi = density of the pollutant i in grams per litre at normal temperature and pressure (273.2 K and 101.33 kPa),

                   kh = humidity correction factor used for the calculation of the mass emissions of oxides of nitrogen. There is no humidity