Document ID: chunk:federal_register_of_legislation:F2023L00129:reg:13:p35
Version: federal_register_of_legislation:F2023L00129
Segment Type: reg
Provision Reference: reg 13 (pt 35/56)
Character Range: 392559–395253

cent.
 If, with the analyzer in the most common range, the ozonator cannot give a reduction from 80 per cent to 20 per cent according to paragraph 9.3.6.5., the highest range which will give the reduction shall be used.
9.3.7. Adjustment of the FID
9.3.7.1. Optimization of the detector response
 The FID shall be adjusted as specified by the instrument manufacturer. A propane in air span gas shall be used to optimize the response on the most common operating range.
 With the fuel and airflow rates set at the manufacturer's recommendations, a 350 ± 75 ppm C span gas shall be introduced to the analyzer. The response at a given fuel flow shall be determined from the difference between the span gas response and the zero gas response. The fuel flow shall be incrementally adjusted above and below the manufacturer's specification. The span and zero response at these fuel flows shall be recorded. The difference between the span and zero response shall be plotted and the fuel flow adjusted to the rich side of the curve. This is the initial flow rate setting which may need further optimization depending on the results of the hydrocarbon response factors and the oxygen interference check according to paragraphs 9.3.7.2. and 9.3.7.3. If the oxygen interference or the hydrocarbon response factors do not meet the following specifications, the airflow shall be incrementally adjusted above and below the manufacturer's specifications, repeating paragraphs 9.3.7.2. and 9.3.7.3. for each flow.
 The optimization may optionally be conducted using the procedures outlined in SAE paper No. 770141.
9.3.7.2. Hydrocarbon response factors
 A linearity verification of the analyzer shall be performed using propane in air and purified synthetic air according to paragraph 9.2.1.3.
 Response factors shall be determined when introducing an analyzer into service and after major service intervals. The response factor (rh) for a particular hydrocarbon species is the ratio of the FID C1 reading to the gas concentration in the cylinder expressed by ppm C1.
 The concentration of the test gas shall be at a level to give a response of approximately 80 per cent of full scale. The concentration shall be known to an accuracy of ±2 per cent in reference to a gravimetric standard expressed in volume. In addition, the gas cylinder shall be preconditioned for 24 hours at a temperature of 298 K ± 5 K (25 °C ± 5 °C).
 The test gases to be used and the relative response factor ranges are as follows:
(a) Methane and purified synthetic air 1.00  rh  1.15;
(b) Propylene and purified synthetic air 0.90  rh  1.1;
(c) Toluene and purified synthetic air 0.90  rh  1.1.
 These values are relative to a