IS 1141:1993 is the Indian Standard (BIS) for seasoning of timber- code of practice. This code provides guidelines for the proper seasoning of timber using air-drying and kiln-drying methods. It specifies kiln drying schedules based on the refractoriness of different timber species to reduce moisture content safely, preventing defects like warping, splitting, and fungal decay.
Seasoning of timber- Code of practice
| Parameter | IS Value | International | Source |
|---|---|---|---|
| Kiln Schedule Prescription | Provides 7 detailed, prescriptive schedules (I-VII) based on timber refractoriness (Clause 8.7 & Appendix A). | Schedules are not prescribed; standards define the required end-result. Operators develop schedules based on guidance. | EN 14298:2021 |
| Moisture Content (Reference Method) | Oven drying method (Clause 10.1.1). | Oven dry method (Clause 5). | BS EN 13183-1:2002 |
| Moisture Gradient Assessment | Qualitative assessment via prong test for case-hardening/stresses (Clause 12.1.2). | Quantitative measurement of 'shell' and 'core' moisture content, with specified maximum allowable differences for quality classes. | AS/NZS 4787:2001 |
| Basis for Target Moisture Content | Prescribed in tables based on end-use and geographical zone in India (Appendix B). | Based on the equilibrium moisture content (EMC) of the intended in-service environment; often specified by the purchaser. | ASTM D4933-99 (2019) |
| Stacking Sticker Thickness | Prescribed as 25 mm for timber up to 50 mm thick (Clause 5.3.1). | Recommends a range, typically 12 mm to 25 mm, depending on species and thickness, but is not mandatory. | AS/NZS 4787:2001 |
| Case-Hardening Test Sample Thickness | Specimen of 'about 25 mm thick' is cut from the sample board (Clause 12.1.2). | Specimen 'at least 20 mm thick' is cut from the board (Clause A2.2). | AS/NZS 4787:2001 |