BS 4978:2007+A2:2017
$102.76
Visual strength grading of softwood. Specification
| Published By | Publication Date | Number of Pages |
| BSI | 2017 | 20 |
This British Standard specifies a methodology for the visual strength grading of softwood for structural use.
The permissible limits of characteristics are specified for two visual strength grades of softwood:
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GS ‒ General Structural; and
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SS ‒ Special Structural.
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PDF Catalog
| PDF Pages | PDF Title |
|---|---|
| 4 | Foreword |
| 5 | 1 Scope 2 Normative references 3 Terms and definitions |
| 6 | 4 Strength graded timber |
| 7 | Figure 1 — Edge, face and margin areas |
| 8 | 5 Grade requirements 6 Measurement of characteristics |
| 9 | Figure 2 — Knot projection |
| 11 | Figure 3 — Typical knot area ratios and the resulting grades |
| 12 | Figure 4 — Measurement of rate of growth |
| 13 | Figure 5 — Amounts of wane Figure 6 — Measurement of bow, spring and twist |
| 14 | Table 1 Permissible limits for the GS and SS visual strength grades |
| 15 | 7 Marking�) Figure 7 Example of a mark on visually strength graded softwood |
| 16 | Annex A (normative) Determination of the knot area ratio in cases of dispute Annex B (normative) The control and supervision of visual strength grading operations |
| 18 | Bibliography |
