This standard outlines the methods for identifying, measuring, and evaluating various natural and biological defects in timber logs, including knots, shakes, splits, sweep, and decay. It establishes a uniform practice for grading, quality assessment, and valuation of logs prior to sawing or further processing.
Methods of measurement and evaluation of defects in timber, Part 1: Logs
Quick Reference Values
Measurement of knotMaximum distance between lines enclosing the knot parallel to the longitudinal edges
Measurement of bowMaximum deviation from a straight edge connecting the two ends of the face
Measurement of cupMaximum deviation from a straight edge placed transversely across the width of the face
Measurement of springMaximum deviation from a straight edge connecting the two ends of the edge
Measurement of slope of grainMeasured over a distance of not less than 250 mm
Practical Notes
Moisture content heavily influences warp; always record the moisture content at the time of evaluating bow, cup, spring, and twist.
When measuring knots, it is crucial to distinguish between live (sound) knots and dead (loose/decayed) knots, as their structural implications differ.
Wane should be measured at the point of maximum reduction of the cross-section.