IS 8720:1978 is the Indian Standard (BIS) for methods of sampling of timber scantlings from depots and their conversion for testing. 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
| Parameter | IS Value | International | Source |
|---|---|---|---|
| Sampling Basis | Lot-based acceptance sampling from a depot, with a fixed sampling schedule. | Statistically-based representative sampling; plan depends on population variability and test objectives. | ISO 3129:2019 |
| Sample Size from a Lot of 100 Scantlings | 8 scantlings | Not prescribed; must be determined by a statistical sampling plan. | ISO 3129:2019 |
| Sample Length from Scantling | A length of 1.2 m shall be cut from each selected scantling. | Not specified; length must be sufficient to yield the required number of test specimens clear of defects. | ASTM D143-21 |
| Specimen Conversion Guide | Mandatory cutting diagram (Fig. 1) must be followed. | Provides recommended cutting diagrams but allows flexibility based on material and objectives. | ASTM D143-21 |
| Target Test Standard | Specimens prepared for tests as per IS 1708. | Specimens prepared for tests as per the ISO 13061 series. | ISO 3129:2019 |
| Traceability | Prescribes a specific marking scheme for lot, scantling, and test sticks. | Requires a complete and unambiguous marking system to be used and documented, but does not prescribe a specific format. | ISO 3129:2019 |