BS EN 1309-3:2018 pdf download.Round and sawn timber – Methods of measurements
1 Scope
This European Standard specifies the methodology for measurement of features – in relation to wood structure, biological agencies and other damage – taken into account in the visual grading:
a) for appearance – of sawn, processed and round timber;
b) for serviceability – of sawn and processed timber (identified in EN 1611-1 as the integrity of the timber).
When the standard is applied the methodology of measurement used shall be stated.It is not applicable to structural timber for which strength grading in accordance with EN 14081-1 is required.
This standard applies to hardwood and softwood sawn timber, both square edged and un- edged, to processed timber and to round timber.
It does not apply to tropical timber.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
EN 844 (all parts), Round and sawn timber一Terminology
EN 1611- 1, Sawn timber一Appearance grading of softwoods一Part 1: European spruces, firs, pines and Douglas firs
EN 14081- 1, Timber structures一Strength graded structural timber with rectangular cross section一Part 1: General requirements
5.1.2 Appearance assessment methodology
5.1.2.1 General
Consider each knot individually, except for ‘cat’s paw’. Measure knots on a part or all the surface of the face(s) or the edge(s) as specified by the grading rule used. In the case of a knot with bark on its perimeter, the measurement of the knot s hall include the bark. Figures 1 to 6 show the categories of knots that shall be measured. Each figure is accompanied by the corresponding formula that is generally the arithmetic average of the minor axis [a) and major axis (b] of the knot(d= [a + b)/2]. Measure the width on each axis and derive the size from the formula. For each grade, the maximum size and number of knots per piece or per unit measure is stated in the grading standards / grading rules. A larger number of smaller knots may be permitted provided their cumulative measure does not exceed the maximum knot size multiplied by the number permitted within a grade, which can be expressed as:
BS EN 1309-3:2018 pdf download
