How many scantlings do I need to sample from a truckload of 120 pieces?

For a lot size between 91 and 150, you need to select 8 scantlings for testing, as per Table 1.

What is the purpose of this standard?

It standardizes how to obtain a representative sample of timber from a large batch and how to cut it into smaller pieces for quality testing.

Does this standard tell me how to test the timber's strength?

No. This standard is only for sampling and preparing test specimens. The actual test procedures are covered in IS 1708 (Methods of testing of small clear specimens of timber).

IS 8720

: 1978

Methods of sampling of timber scantlings from depots and their conversion for testing

CurrentSpecializedTesting MethodMaterials Science · Timber and Timber Stores

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This standard provides the methodology for sampling timber scantlings from a depot or lot for testing purposes. It specifies the scale of sampling based on lot size and details the procedure for selecting and converting these scantlings into small, clear specimens required for physical and mechanical tests.

Methods of sampling of timber scantlings from depots and their conversion for testing

Quick Reference Values

Sample size for lot of 51 to 90 scantlings5

Sample size for lot of 91 to 150 scantlings8

Sample size for lot of 151 to 280 scantlings13

Minimum recommended length of scantling2.4 m

Minimum recommended cross-section of scantling50 mm x 50 mm

Practical Notes

The selection of scantlings should be truly random to ensure the sample is representative of the entire lot. Avoid picking only the most accessible pieces.

During conversion into test specimens, the goal is to obtain 'clear' samples, which means they must be free from defects like knots, cracks, decay, and insect attack.

Proper marking and recording are crucial to maintain traceability from the final test result back to the specific scantling and its original lot.