ECOTEST VIRTUOSO RKG-14 Operating Manual page 73

3. One of the measurement types is measurement of NORM activity inside
the building. The thickness of the walls, floor and ceiling should be no less than 20
cm (with less thickness the measurement result will be somewhat underestimated).
In case of such measurement, it is sufficient to place the detector in any point in the
room (preferably closer to the center). If the detector is placed close to one of the
walls, the NORM activity of that wall will produce the largest effect on calculation
of the average activity.
Figure 2.57 – Measurement inside a room
71