BS EN ISO 8970:2020

What is ISO 8970 about?  

ISO 8970 discusses the requirements for timber density to test joints made with mechanical fasteners in timber structures. 

ISO 8970 specifies a method based on density used for the selection of pieces of wood that determines the strength and stiffness properties of joints between members of structural timber. 

ISO 8970 is intended to be used in conjunction with a test standard specifying a test method. 

Note 1: Under ISO 8970 it is assumed that the wood pieces are conditioned to the relevant conditions, that the wood density is normally distributed and that any deviations are reported. 

Note 2: Under ISO 8970 it is emphasized that wood density is only one of the properties that can influence the strength of a joint. 

Note 3: ISO 8970 only applies to specimens of structural timber. 

Who is ISO 8970 for? 

ISO 8970 on requirements for timber density is relevant to: 

• Timber structure manufacturers 
• Construction companies 
• Builders 
• Civil engineers 

Why should you use ISO 8970?  

While testing the joints made with mechanical fasteners in timber structures the selected pieces of wood must have a density distribution comparable to the timber to which the test result is intended to be applied. This is done using a sampling method. 

After the sampling method, the results can be used directly to determine the characteristic value of the strength parameter. 

As it is often difficult to obtain a variation of the density similar to that allowed in a strength class, a correction method is also used to obtain a corrected coefficient of variation for the strength parameter. 

The method mentioned under ISO 8970 provides an efficient selection of the pieces of wood based on density to determine the strength and stiffness of joints in timber structures and thus, assists in determining the strength of structures made. 

ISO 8970 assists in reducing any damages to the timber structures due to weakened joints by providing a correction method for the strength parameter. 

What’s changed since the last update?  

BS EN ISO 8970:2020 supersedes BS EN ISO 8970:2010 which is withdrawn. BS EN ISO 8970:2020 has revised its sampling method and has provided a correction method with respect to BS EN ISO 8970:2010.