EN ISO 8970-2020 pdf free.Timber structures — Testing of joints made with mechanical fasteners — Requirements for timber density.
This document specifies a method based on density,for the selection of pieces of wood used indetermining the strength and stiffness properties of joints between members of structural timbermade with mechanical fasteners. It is intended to be used in conjunction with a test standard specifyinga test method.
lt is assumed that the wood pieces are conditioned to the relevant conditions, that the wood density isnormally distributed and that any deviations are reported.
This document is applicable only to specimens of structural timber.
NOTE lt is emphasized that the wood density is only one of the properties that can influence the strength ofa joint. Other relevant properties are, for example, growth-ring size and orientation, toughness and hardness.
The following documents are referred to in the text in such a way that some or all of their contentconstitutes requirements of this document. For dated references, only the edition cited applies.Forundated references, the latest edition of the referenced document (including any amendments) applies.IS0 13061-2,Physical and mechanical properties of wood一Test methods for small clear wood specimens—Part 2: Determination of density for physical and mechanical tests.The wood shall be at equilibrium at a relative humidity(RH) of (65 ± 5) % and a temperature of(20 ± 2)C at the time of testing.It shall be reported whether the wood was dried or moistened duringthe conditioning.
NOTE The moisture content at equilibrium is lower when reached by moistening than if reached by drying.which can affect the test results. The product test standard can specify if the equilibrium condition is to bereached through drying.
The density for the actual moisture content shall be determined in accordance with ISO 13061 2.
This density is referred to as pw in ISO 13061-2.The moisture content need not be determined, unlessthe product test standard requires it.
If other conditions, such as tropical conditions, are used, they shall be reported.5.2Sampling method and requirements
The sampling method is based on the principle that all selected pieces have a density distributioncomparable with that of the timber to which the test results are applied. This may be assumed ifFormula (1) and Formula (2) are fulfilled. The observed strengths may then be used directly forcalculating characteristic values of the strength.NOTE The test results apply only to the timber species or the group of timber species used.
The wood shall be of uniform quality and without localized defects that can influence the test results.EN ISO 8970 pdf download.