Division 9.4.5.5 Sample flow meter for batch sampling

A sample flow meter shall be used to determine sample flow rates or total flow sampled into a batch sampling system over a test interval. The difference between two flow meters may be used to calculate sample flow into a dilution tunnel e.g. for partial flow dilution PM measurement and secondary dilution flow PM measurement. Specifications for differential flow measurement to extract a proportional raw exhaust gas sample is set out in point 8.1.8.6.1 and the calibration of differential flow measurement is given in point 8.1.8.6.2.

Overall system for the sample flow meter shall meet the calibration requirements set out in point 8.1.8.