Overview
ISO 2301:1973 - "Sawn timber of broadleaved species - Defects - Measurement" is an international standard that specifies methods for measuring defects in sawn hardwoods. Published in 1973 (first edition) and issued in English, French and Russian, the standard covers unplaned sawn timber and timber surfaced to size or planed but without profiling. It provides standardized measurement techniques that support the classification given in ISO 2299 (Defects - Classification) and refers to illustrative figures for each measurement method.
Key topics and technical requirements
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Scope and units
- Measurements may be expressed in absolute units (millimetres, centimetres) or relative values (fractions of the corresponding side or length of the piece).
- Counts and frequencies are expressed per metre (3.28 ft) of length or per whole piece.
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Knots
- Two principal measurement methods:
a) distance between tangents to the knot perimeter drawn parallel to the piece arrises;
b) minimum diameter of the knot cross‑section.
- Specific rules for round, oval, splay (spike), branched, arris, cluster and double knots, including when to sum constituent knot sizes.
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Shakes (splits and checks)
- Face, edge and end shakes are measured by penetration depth (mm or fraction of thickness/width) and length (cm or fraction of piece length).
- End ring shakes: measured by chord if less than half a circle, by diameter if half circle or greater.
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Wood structure irregularities and discoloration
- Includes slope of grain (measured over a length at least twice the piece width and expressed as percentage), inbark (depth/length/width and number per metre), tension wood, curly grain, false heartwood, flecks, included sapwood, tannin coloration, etc.
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Biological and sawing defects
- Fungal defects: measured in centimetres or as percentage of affected surface area.
- Insect damage (worm-holes): number of galleries/holes per metre or per piece.
- Sawing defects (wane): measured by maximum difference between corresponding side widths.
Applications and users
ISO 2301 is practical for:
- Saw mill operators and graders implementing consistent timber grading and quality control.
- Timber traders and buyers specifying acceptance criteria for hardwood sawn timber.
- Wood product manufacturers, furniture and joinery producers requiring consistent defect measurement.
- Standards bodies and testing laboratories aligning inspection and classification with ISO 2299.
Related standards
- ISO 2299 - Sawn timber of broadleaved species - Defects - Classification (used together with ISO 2301 for grading and specification).
Keywords: ISO 2301, sawn timber, broadleaved species, defects measurement, knots measurement, shakes, slope of grain, timber grading, ISO 2299.
