Vaisala SHM40 - Manual (Page 22)

USER'S GUIDE____________________________________________________________________
20 __________________________________________________________________ M211423EN-B
Preparations for Measurement
Before you can measure the humidity of concrete using the borehole
method, you must prepare the borehole and wait for humidity to stabilize.
The preparations can be started on a freshly cast concrete if desired.
CAUTION Before starting, read section Measurement Depth on page 16.
Appropriate depth of the borehole is critical for accuracy.
NOTE For best results, insert the probe to the plastic tube immediately after you
are finished preparing the borehole, and leave it to stabilize for three
days.
NOTE Make sure that the tube and the probe are not colder than the concrete
when inserting them: this might cause condensation on the probe and the
readings can be incorrect.