1.4.1 The exhaust gas sample should be representative
of the average exhaust emission from all the engine's cylinders. The
gas sampling system should comply with the NOx Technical Code, paragraph 5.9.3.
1.4.2 The exhaust gas sample should be drawn from
a zone anywhere between 10%-90% of the duct diameter.
1.4.3 In order to facilitate the installation
of the sampling probe, an example of a sample point connection flange
is given in appendix 1.
1.4.4 The exhaust gas sample for NOx measurement
should be maintained so as to prevent NO2 loss via water
or acid condensation in accordance with analysing equipment manufacturer's
recommendations.
1.4.5 The gas sample should not be dried by chemical
driers.
1.4.6 The gas sampling system should be capable
of being verified to be free of ingress leakage in accordance with
analysing equipment manufacturer's recommendations.
1.4.7 An additional sample point adjacent to that
used should be provided to facilitate quality control checks on the
system.