1.1 这些实践涵盖了适用于非矩形结构木构件的视觉应力分级原则，通常用于原木建筑。这些实践旨在补充第节中列出的ASTM标准 2. ，包括锯材和圆木的应力分级。这些规程涵盖的构件也可用于除原木建筑以外的建筑类型。 1.2 本文中用作插图的分级规定并非旨在确定购买等级，而是为了说明应力分级原则如何应用于原木建筑中使用的构件。商业应力等级的详细分级规则作为采购规范，由制定和维护此类规则的机构制定和发布，并运营涵盖各种物种的检查设施。 1.3 以英寸-磅为单位的数值应视为标准值。括号中给出的值是到国际单位制的数学转换，仅供参考，不被视为标准值。 1.4 本标准并非旨在解决与其使用相关的所有安全问题（如有）。本标准的用户有责任在使用前制定适当的安全、健康和环境实践，并确定监管限制的适用性。 1.5 本国际标准是根据世界贸易组织技术性贸易壁垒（TBT）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》中确立的国际公认标准化原则制定的。

1.1 These practices cover the visual stress-grading principles applicable to structural wood members of nonrectangular shape, as typically used in log buildings. These practices are meant to supplement the ASTM standards listed in Section 2 , which cover stress-grading of sawn lumber and round timbers. Pieces covered by these practices may also be used in building types other than log buildings. 1.2 The grading provisions used as illustrations herein are not intended to establish grades for purchase, but rather to show how stress-grading principles are applied to members used in log buildings. Detailed grading rules for commercial stress grades which serve as purchase specifications are established and published by agencies that formulate and maintain such rules and operate inspection facilities covering the various species. 1.3 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. 1.4 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use. 1.5 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.