ČSN EN 1912
Konstrukční dřevo - Třídy pevnosti - Přiřazení vizuálních tříd a dřevin

ČSN EN 1912 (73 1713)

This document lists visual strength grades, species and sources of timber, and specifies the strength classes to which they are assigned. The assignments listed are for strength classes documented in EN 338.
Structural timber that has previously been graded cannot be re-graded to the same or different grades unless the method of determining characteristic values has made allowances for changes to the timber population caused by the previous grading.
NOTE 1 - Consequently, the assignments stated in this document apply to timber that has not been previously strength graded in a way that introduces a bias on the population of timber to be graded, as compared to ungraded material.
Species/grades or species combination/grades are assigned to strength classes in accordance with EN 14081-1 and supporting standards, such as EN 384.
This document contains a list of assignments but is not intended to be exhaustive.
NOTE 2 - Timber graded by machine to EN 14081-1 is graded directly to the strength classes and marked accordingly. Machine grading is therefore not referenced in this document.