Standard Practice for Establishing Allowable Properties for Visually-Graded Dimension Lumber from In-Grade Tests of Full-Size Specimens

Importancia y uso:

4.1 The procedures described in this practice are intended to be used to establish allowable stress and modulus of elasticity values for solid sawn, visually graded dimension lumber from In-Grade type test data. These procedures apply to the tested and untested sizes and grades when an adequate data matrix of sizes and grades exists. In addition, the methodology for establishing allowable stress and modulus of elasticity values for combinations of species and species groups is covered. Allowable stress and modulus of elasticity values may also be developed for a single size or a single grade of lumber from test data.

4.2 Methods for establishing allowable stress and modulus of elasticity values for a single size/grade test cell are covered in Practice D2915. The appropriateness of these methods to establish allowable stress and modulus of elasticity values is directly dependent upon the quality and representativeness of the input test data.

4.3 A monitoring program shall be established to periodically review the continued applicability of allowable properties derived by this practice. A monitoring program will establish data sets that are either the same as, above, or below the data that was used to develop the current allowable properties. Upon detection of a statistically significant downward shift, evaluation of the data and confirmation of remedial actions shall be undertaken. When evaluation is not undertaken or the results of the evaluation indicate an adjustment to allowable properties is appropriate, a reassessment shall be conducted to re-establish allowable properties.

Note 5: It is recognized that over time there is the potential for changes in the raw material or product mix. In response to this a monitoring program must be conducted to ensure design values derived by this practice are not invalidated by such changes. If the data collected with a monitoring provides evidence of a statistically significant downward shift in lumber properties an evaluation program in accordance with the procedures of this practice is needed to detect and confirm that responses to such changes are appropriate. Evaluation, if undertaken, provides a means for responding to the data and assessing if the actions taken are sufficient. Following the confirmation of a statistically significant downward shift, reassessment of values shall be conducted if evaluation is either not undertaken or does not adequately address the downward shift.

Subcomité:

D07.02

Referida por:

D7199-20, D6555-23, D6570-18AR23E01, D4444-13R18, D6251_D6251M-23, D7381-07R21E01, D2915-25, D5457-23, D6782-19, D5055-24, D6255_D6255M-18, D6874-22A, D6039_D6039M-18

Volúmen:

04.10

Número ICS:

79.040 (Wood, sawlogs and sawn timber)