as dry, moist, wet, and saturated for each test location.
Draw "contour" lines between the values to enclose each
given value area. A moisture pattern is immediately
For additional clarity, color the enclosed areas with a
specific color pencil to designate the various moisture
Intelligent action can now be taken as to where repairs
should be commenced on the roof and over what area.
It may be obvious where the moisture is coming from...
flashing, a previously unobserved puncture, crack, or low
spot, once the pattern is drawn.
1-36. RADIATION SAFETY
Density is not a factor on the roof, therefore the shutter
will be kept closed and gamma radiation beneath the
tester is negligible.
A typical industrial built-up roof will be more than 8
above head height of occupants of space beneath the
roof. Neutron radiation at that distance is less than
0.025 mrem/hr. Since the tester is constantly being
moved from test spot to test spot, there is no radiation
danger presented to occupants of the building during
testing and no special provisions should be taken for
The operator will take many readings in a day, however,
and good practice dictates stepping back from the tester
5 or more while the tester is counting.