AS/NZS 4787:2001

Sets out procedures for specifying and verifying the moisture content of seasoned solid timber. Provides a range of drying quality classes for timber dried in kilns or by other means where the result is a population of timber with a predictable scater of moisture contents. Other drying quality criteria such as checking, collapse and distortion are detailed in an appendix.

This Standard sets out procedures for specifying the moisture content and other drying quality criteria of seasoned solid wood products and is primarily intended for use by processors, merchants and users, to assess the drying quality of a pack, stack or charge of dry timber. It describes drying quality classes and gives sampling methods for testing products to establish compliance.This Standard is for use with softwood or hardwood boards up to 80 mm in thickness, where the moisture contents of boards in a quantity exhibit a single skewed distribution. (At the end of drying there is usually variability in the between-board moisture content distribution with a longer tail above than below the most common moisture content value.) Where such a single skewed distribution does not exist, then this Standard may be used, provided upper or upper and lower cut-off limits are set.NOTES: 1 It is intended that the Standard provide a uniform methodology for the assessment of drying quality for the timber industry. For example, processors may use the Standard to define procedures for quality assessment of dried timber as part of process quality control documentation, or to detail product quality specifications in supply agreements with merchants or users.2 Where the Standard is used beyond a drying facility, caution is recommended, due to the following reasons:(a) Consignments of timber may comprise a mix of timber from different sources or charges, and the distribution of moisture content may not conform to assumptions made in developing the sampling regime.(b) Timber may be subjected to other influences causing higher moisture content in some materials, e.g. inadequate weather protection, leading to non-conforming distributions of moisture content.In the above two cases the sampling procedure outlined in this Standard may not be adequate.3 Some specifiers may nominate absolute limits.

First published as AS/NZS 4787:2001.