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Standard Practice for Field Calibration and Application of Hand-Held Moisture Meters
Automaticky preložený názov:
Štandardná prax Terénne kalibrácia a aplikácie ručných Merače vlhkosti
NORMA vydaná dňa 1.4.2013
Označenie normy: ASTM D7438-13
Poznámka: NEPLATNÁ
Dátum vydania normy: 1.4.2013
Kód tovaru: NS-38458
Počet strán: 10
Približná hmotnosť: 30 g (0.07 libier)
Krajina: Americká technická norma
Kategória: Technické normy ASTM
Ostatní zařízení na opracování dřeva
Dřevo. Kulatina na řezivo. Řezivo
Dřevěné polotovary
Keywords:
ICS Number Code 79.040 (Wood, sawlogs and sawn timber), 79.080 (Semi-manufactures of timber), 79.120.99 (Other woodworking equipment)
Significance and Use | ||||||||||||
4.1 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 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 circuitry, 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. Appendix X1 is a commentary that provides explanation of the mandatory sections and discussion of historical practices. 4.1.1 This practice provides for calibration and application of wood products that contain commercial characteristics and that reflect the manufacturing environment. 4.2 Most uses of hand-held moisture meters employ correlative (predictive) relationships between the meter reading and wood areas or volumes that exceed that of the direct meter measurement (for example, larger specimens, pieces of lumber, lots). The field calibration section of this practice anticipates the potential need for this type of sampling. These correlative uses are examined in Appendix X3. |
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1. Scope | ||||||||||||
1.1 This practice applies to the measurement of moisture content of solid wood, including solid wood products containing additives, that is, chemicals or adhesives, by hand-held moisture meters under conditions of end-use. 1.1.1 This practice includes calibration, use, and interpretation of meters for conditions that relate to wood product characteristics, such as nonuniform grain and growth ring orientation, and to end-use process conditions, such as moisture gradients. 1.1.2 Meters employing differing technologies may not provide equivalent readings under the same conditions. When this practice has been applied, it is assumed that the referenced meter is acceptable unless otherwise specified. Meters shall have been calibrated by Test Methods D4444. 1.2 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. |
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2. Referenced Documents | ||||||||||||
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1.1.1971
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