ASTM D4444-92(2003)

Hand-held meters provide a rapid means of sampling moisture content of wood-based materials during and after processing to maintain quality assurance and compliance with standards. 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 actual moisture content, a number of other wood variables, environmental conditions, geometry of the measuring probe, and 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.

1.1 These test methods apply to the measurement of moisture content of solid wood, including veneer, and wood products containing additives, that is, chemicals or adhesives (subject to conditions in and ). They also provide guidelines for meter use and calibration by manufacturers and users as alternatives to ovendry measurements.

1.2 Conductance and dielectric meters are not necessarily equivalent in their readings under the same conditions. When these test methods are referenced, it is assumed that either type of meter is acceptable unless otherwise specified. Both types of meters are to be calibrated with respect to moisture content on an oven-dry mass basis as determined by Test Methods D 4442.

1.3 The method title indicates the procedures and uses for each type of meter:

1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.