Timber structures - Calculation and verification of characteristic values
This standard gives statistical methods for the determination of characteristic values from test results on a sample drawn from a clearly defined reference population of e.g. solid wood, fasteners, connectors and wood-based products. The characteristic value is an estimate of the property of the reference population and can be based on a 5-percentile value of strength, resistance or density as well as on a mean value for stiffness. Parametric methods are given for the determination of lower and upper 5-percentiles. The upper 5-percentile is the 95-percentile. This standard is suitable for use with any structural product in the frame of type testing as well as factory production control. Sampling is not covered by this document, but reference is made to the relevant product standards. This standard also provides the acceptance procedure for verification of a lot. Depending on the product, characteristic values determined in accordance with this standard may be used directly or may need additional adjustments specified in the relevant product standards. Note: For example, in the case of solid timber, specific adjustment factors for calculation of characteristic values are given in EN 384.