Standard Test Methods for Standardization and Calibration of In-Line Dry Lumber Moisture Meters

Importancia y uso:

4.1 In-line meters provide a rapid means of detecting moisture content of lumber or wood products in processing (that is, on a continuous production line). Two major uses are monitoring the performance of the drying process (air drying, kiln drying), and providing sorting or identification of material at predetermined levels of moisture content. These measurements are inferential in the sense that physical measurements are made and compared against calibration curves to obtain an indirect measure of moisture content. These measurements are influenced by one or more physical properties such as actual moisture content (average and gradient; see Appendix X5), density, surface moisture, chemical composition, size, and temperature of wood. In addition, the measurements are also influenced by environmental conditions and the design specifications of the meter. The best performance is obtained by an awareness of the effect of each parameter on the meter output and correction of readings as specified by these test methods.

4.2 The two major anticipated users of these test methods are instrument manufacturers whose primary concern is laboratory standardization and calibration, and instrument owners whose primary concern is field standardization and calibration. These test methods present the laboratory and the field as separate tracks (see Appendix X2).

4.2.1 Laboratory Standardization and Calibration—This portion of these test methods is intended for guidance of equipment manufacturers. Specific test recommendations are tailored to the capabilities of a laboratory environment.

4.2.2 Field Standardization and Calibration—The predominant use of in-line meters is in production in which lumber characteristics and environmental conditions reflect actual mill processes. Field standardization and calibration is essential to address or encompass much of the variability in production.

Note 1: Applications using the output of the in-line moisture meter can modify the meter output signals or have inherent response characteristics that are not representative of the meter.

Subcomité:

D07.01

Referida por:

D7438-20R25

Volúmen:

04.10

Número ICS:

79.040 (Wood, sawlogs and sawn timber)

Palabras clave:

in-line moisture meter; moisture content; moisture meters; wood;