AS NZS 2878:2000 pdf free download – Timber-Classification into strength groups

AS NZS 2878:2000 pdf free download – Timber-Classification into strength groups.
1.3.3 Positive strength group
Group to which a limber species is assigned on the basis of the testing of small clear specimens to determine mechanical strength properties for five or more trees (see Appendix A) and tested in accordance with the standard methods referred to in Appendix B.
1.3.4 Provisional strength group
Group to which a timber species is assigned on the basis of density or limited mechanical test data.
NOTE: In Tables 3.1 and 3.2. the pro’isional strength groups are shown within brackets, e.g. (S6).
1.3.5 Seasoned density
Seasoned density refers to the density of timber (including internal moisture) when the moisture content of the timber is 12 percent.
1.3.6 Seasoned timber
For the purposes of this Standard, seasoned timber will be taken to be timber at a moisture content of 1 2 percent.
1.3.7 Ijnseasoned timber
For the purposes of this Standard. unseasoned timber will be taken to refer to timber with a moisture content in excess of 30 percent.
1.3.8 Index properties
For the purposes of this Standard. the term index properties’ is taken to refer to properties that are easily measured and which may be used to verify that a resource has not changed over a period of time. Typical examples of such properties are clear wood density, width of growth rings. knot frequency and log size.
2.2.7 Test report
Each positive strength grouping shall be associated with a publicly available test report that includes the following:
(a) Timber species.
(b) Timber resource.
(C) Specified moisture condition, seasoned or unseasoned.
(d) Sampling procedure uscd,
(e) Name of test laboratory.
(f) Test data obtained including bending strength, modulus of elasticity and moisture content.
(g) Any index properties measured (see Clause 1.3.8).
2.3 PROCEIRI RE FOR PROVISIONAL STRENGTH (;ROUPING
2.3.1 I)ata aailable from mechanical testing
Where there is inadequate evidence for positive strength grouping but there are mechanical test results available from a minimum of three representative trees (see Clause 2.2.1). the predure shall follow that for positive strength grouping (see Clause 2.2) and the strength group shall be lowered by one strength group and placed in brackes to indicate that the grouping is provisional.
2.3.2 Data available only for seasoned density
Where density alone is used to establish the provisional strength group, values of density at 12 percent moisture content are required from at least five representative trees sampled in accordance with Appendix A. The provisional strength group shall he determined from Table 2.4, according to the condition of seasoning. These strength groups shall he placed in brackets to indicate that the grouping is provisional.
NOTE: Because of the imperfect correlation of strength with density. the values listed in Table 2.4 are conservative and i should not be expected that a species positively grouped from its strength properties would necessarily have a density as high as that listed in Table 2.4.