Article 4.4.4.3.

For the determination of a measurement value, the following sampling methods may be used:

1

continuous sampling during the full reference period;

2

sampling during a number of consecutive one-hour intervals covering the full reference period; with this, the measurement value corresponding to the reference period considered is calculated as the time-weighted arithmetic mean of the various measurements;

3

discontinuous sampling, during the reference period, whereby the sampling duration of the various sampling operations may vary by no more than a factor of 2. In that case, depending on the sampling duration used, at least the following number of samples shall be taken:

a)

for a 1-hour reference period:

sampling duration

number of samples

< 2.5 minutes

4

2.5 to 15 minutes

3

15 to 30 minutes

2

>30 minutes

1

b)

for reference periods that last more than 1 hour:

sampling duration

number of samples

< 15 minutes

4 or more

15 to 60 minutes

3 or more

1 to 2 hours

2 or more

2 hours or more

1

If necessary, the sampling duration or frequency must be increased if the indicated sampling duration or frequency does not suffice to obtain a reliable end result.

The reference period may be split into different periods of at least 1 hour if required to obtain a representative end result.

The person carrying out the measurements shall check that the chosen sampling duration and measuring frequency and, where applicable, the splitting up in time provide a representative average for the stipulated reference method.