Standard Test Method for Calibration of Hand-Held Moisture Meters on Gypsum Panels

Abstract

5.1 This Standard Test Method is intended for use in calibrating hand-held meters to accurately read from approximately 30 % to 90 % ERH. Moisture content is related to the ERH or Aw of a material. 5.2 Hand-held meters provide a rapid means of sampling the moisture content of gypsum boards and panels during manufacture and for field inspection during and after building construction. However, these measurements are inferential, that is, electrical parameters are measured and compared against a calibration curve to obtain an indirect measure of moisture content. The electrical measurements are influenced by the actual moisture content, a number of other gypsum board and panel variables, environmental conditions, the geometry of the measuring probe, and the design of the meter. The maximum accuracy can only be obtained by an awareness of the effect of each parameter on the meter output and correction of readings as specified by these test methods. 5.3 Electrical conductance and dielectric meters are not necessarily equivalent in their readings under the same conditions. When this test method is referenced, the type of meter that is being used must be reported with the relevant ranges for precision and bias as specified in this standard. 5.4 Both types of meters are to be calibrated with respect to ERH as described in this standard.