1.1 本规程涵盖了根据全尺寸视觉分级实心锯材的“级内”试验确定弯曲、平行于纹理的张力、平行于晶粒的压缩和结构设计的弹性模量值的容许应力值的原则和程序。本规程还涵盖了定期监测的程序，以及在必要时对指定设计值进行评估和可能重新评估的附加程序。本实践侧重于但不限于使用实践中包含的概念的成绩 D245 并在美国软木木材PS 20下开发和解释。 1.2 本实践中使用的程序的一个基本假设是，所选和测试的样本代表了正在评估的整个全球人口。这种方法与历史上的透明木材方法是一致的，该方法为视觉分级的木材分配了一个允许的属性，该木材代表了一个物种或物种组的整个生长范围。应尽一切努力确保测试样本按等级和大小代表总体（见 7.1.1 和 7.1.2 ). 1.3 由于涉及的试样数量和要评估的机械性能数量，有必要采用一种方法来评估数据，并为测试和未测试的等级/尺寸单元分配允许的性能。受试细胞的取样和分析见实施规程 D2915 机械试验方法见试验方法 D198 和 D4761 本规程涵盖了从In为尺寸木材分配容许应力和弹性模量值的必要程序- 等级测试。该实践包括允许将容许应力和弹性模量值分配给未经测试的尺寸和等级以及一些未经测试性能的方法。该实践包括定期监测物种或物种组的程序，以量化产品的潜在变化，并通过评估和重新评估来验证指定的设计值。 注1: 在实施北美级内试验程序时，使用实践程序计算了结构设计中垂直于晶粒压缩和平行于晶粒剪切的容许应力值 D245 . 1.4 此做法仅适用于尺寸木材。 1.5 以英寸-磅单位表示的值应被视为标准值。括号中给出的值是对国际单位制的数学转换，仅供参考，不被视为标准值。 1.6 本标准并不旨在解决与其使用相关的所有安全问题（如果有的话）。本标准的使用者有责任在使用前建立适当的安全、健康和环境实践，并确定监管限制的适用性。 1.7 本国际标准是根据世界贸易组织技术性贸易壁垒委员会发布的《关于制定国际标准、指南和建议的原则的决定》中确立的国际公认的标准化原则制定的。 =====意义和用途====== 4.1 本规程中描述的程序旨在用于确定in的实心锯、视觉分级尺寸木材的容许应力和弹性模量值- 等级型式试验数据。当存在足够的尺寸和等级数据矩阵时，这些程序适用于测试和未测试的尺寸和品位。此外，还介绍了确定物种和物种组组合的容许应力和弹性模量值的方法。也可以根据测试数据为单一尺寸或单一等级的木材制定许用应力和弹性模量值。 4.2 确定单个尺寸/等级测试单元的许用应力和弹性模量值的方法见实施规程 D2915 这些方法确定容许应力和弹性模量值的适当性直接取决于输入测试数据的质量和代表性。 4.3 应制定监测计划，定期审查本规程得出的允许特性的持续适用性。监测程序将建立与用于开发当前允许特性的数据相同、高于或低于这些数据的数据集。在检测到统计上显著的向下偏移后，应对数据进行评估并确认补救措施。 当未进行评估或评估结果表明对允许的性能进行调整是适当的时，应进行重新评估以重新建立允许的性能。 注5: 人们认识到，随着时间的推移，原材料或产品组合有可能发生变化。为此，必须进行监测计划，以确保通过这种做法得出的设计值不会因这些变化而无效。如果通过监测收集的数据提供了木材性能在统计上显著下降的证据，则需要根据本规程的程序进行评估，以检测并确认对此类变化的反应是适当的。 如果进行评估，则提供了一种对数据作出回应并评估所采取行动是否充分的手段。在确认统计上显著的向下偏移后，如果评估没有进行或没有充分解决向下偏移的问题，则应重新评估数值。

1.1 This practice covers the principles and procedures for establishing allowable stress values for bending, tension parallel to grain, compression parallel to grain and modulus of elasticity values for structural design from “in-grade” tests of full-size visually graded solid sawn dimension lumber. This practice also covers procedures for periodic monitoring, and additional procedures, if needed, for evaluation and possible reassessment of assigned design values. This practice is focused on, but is not limited to, grades which used the concepts incorporated in Practice D245 and were developed and interpreted under American Softwood Lumber PS 20. 1.2 A basic assumption of the procedures used in this practice is that the samples selected and tested are representative of the entire global population being evaluated. This approach is consistent with the historical clear wood methodology of assigning an allowable property to visually graded lumber which was representative of the entire growth range of a species or species group. Every effort shall be made to ensure the test sample is representative of population by grade and size (see 7.1.1 and 7.1.2 ). 1.3 Due to the number of specimens involved and the number of mechanical properties to be evaluated, a methodology for evaluating the data and assigning allowable properties to both tested and untested grade/size cells is necessary. Sampling and analysis of tested cells are covered in Practice D2915 . The mechanical test methods are covered in Test Methods D198 and D4761 . This practice covers the necessary procedures for assigning allowable stress and modulus of elasticity values to dimension lumber from In-Grade tests. The practice includes methods to permit assignment of allowable stress and modulus of elasticity values to untested sizes and grades, as well as some untested properties. The practice includes procedures for periodic monitoring of the species or species group to quantify potential changes in the product and verification of the assigned design values through evaluation and reassessment. Note 1: In the implementation of the North American In-Grade test program, allowable stress values for compression perpendicular to grain and shear parallel to grain for structural design were calculated using the procedures of Practice D245 . 1.4 This practice only covers dimension lumber. 1.5 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard. 1.6 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use. 1.7 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee. ====== Significance And Use ====== 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.