ASTM D3957-09R20

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.